-;;;; -*-scheme-*-
-;;;;
-;;;; Copyright (C) 2001, 2003, 2006, 2009, 2010 Free Software Foundation, Inc.
-;;;;
-;;;; This library is free software; you can redistribute it and/or
-;;;; modify it under the terms of the GNU Lesser General Public
-;;;; License as published by the Free Software Foundation; either
-;;;; version 3 of the License, or (at your option) any later version.
-;;;;
-;;;; This library is distributed in the hope that it will be useful,
-;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
-;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-;;;; Lesser General Public License for more details.
-;;;;
-;;;; You should have received a copy of the GNU Lesser General Public
-;;;; License along with this library; if not, write to the Free Software
-;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
-;;;;
-\f
-
-;;; Portable implementation of syntax-case
-;;; Originally extracted from Chez Scheme Version 5.9f
-;;; Authors: R. Kent Dybvig, Oscar Waddell, Bob Hieb, Carl Bruggeman
-
-;;; Copyright (c) 1992-1997 Cadence Research Systems
-;;; Permission to copy this software, in whole or in part, to use this
-;;; software for any lawful purpose, and to redistribute this software
-;;; is granted subject to the restriction that all copies made of this
-;;; software must include this copyright notice in full. This software
-;;; is provided AS IS, with NO WARRANTY, EITHER EXPRESS OR IMPLIED,
-;;; INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY
-;;; OR FITNESS FOR ANY PARTICULAR PURPOSE. IN NO EVENT SHALL THE
-;;; AUTHORS BE LIABLE FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES OF ANY
-;;; NATURE WHATSOEVER.
-
-;;; Modified by Mikael Djurfeldt <djurfeldt@nada.kth.se> according
-;;; to the ChangeLog distributed in the same directory as this file:
-;;; 1997-08-19, 1997-09-03, 1997-09-10, 2000-08-13, 2000-08-24,
-;;; 2000-09-12, 2001-03-08
-
-;;; Modified by Andy Wingo <wingo@pobox.com> according to the Git
-;;; revision control logs corresponding to this file: 2009, 2010.
-
-
-;;; This file defines the syntax-case expander, macroexpand, and a set
-;;; of associated syntactic forms and procedures. Of these, the
-;;; following are documented in The Scheme Programming Language,
-;;; Fourth Edition (R. Kent Dybvig, MIT Press, 2009), and in the
-;;; R6RS:
-;;;
-;;; bound-identifier=?
-;;; datum->syntax
-;;; define-syntax
-;;; fluid-let-syntax
-;;; free-identifier=?
-;;; generate-temporaries
-;;; identifier?
-;;; identifier-syntax
-;;; let-syntax
-;;; letrec-syntax
-;;; syntax
-;;; syntax-case
-;;; syntax->datum
-;;; syntax-rules
-;;; with-syntax
-;;;
-;;; Additionally, the expander provides definitions for a number of core
-;;; Scheme syntactic bindings, such as `let', `lambda', and the like.
-
-;;; The remaining exports are listed below:
-;;;
-;;; (macroexpand datum)
-;;; if datum represents a valid expression, macroexpand returns an
-;;; expanded version of datum in a core language that includes no
-;;; syntactic abstractions. The core language includes begin,
-;;; define, if, lambda, letrec, quote, and set!.
-;;; (eval-when situations expr ...)
-;;; conditionally evaluates expr ... at compile-time or run-time
-;;; depending upon situations (see the Chez Scheme System Manual,
-;;; Revision 3, for a complete description)
-;;; (syntax-violation who message form [subform])
-;;; used to report errors found during expansion
-;;; ($sc-dispatch e p)
-;;; used by expanded code to handle syntax-case matching
-
-;;; This file is shipped along with an expanded version of itself,
-;;; psyntax-pp.scm, which is loaded when psyntax.scm has not yet been
-;;; compiled. In this way, psyntax bootstraps off of an expanded
-;;; version of itself.
-
-;;; This implementation of the expander sometimes uses syntactic
-;;; abstractions when procedural abstractions would suffice. For
-;;; example, we define top-wrap and top-marked? as
-;;;
-;;; (define-syntax top-wrap (identifier-syntax '((top))))
-;;; (define-syntax top-marked?
-;;; (syntax-rules ()
-;;; ((_ w) (memq 'top (wrap-marks w)))))
-;;;
-;;; rather than
-;;;
-;;; (define top-wrap '((top)))
-;;; (define top-marked?
-;;; (lambda (w) (memq 'top (wrap-marks w))))
-;;;
-;;; On the other hand, we don't do this consistently; we define
-;;; make-wrap, wrap-marks, and wrap-subst simply as
-;;;
-;;; (define make-wrap cons)
-;;; (define wrap-marks car)
-;;; (define wrap-subst cdr)
-;;;
-;;; In Chez Scheme, the syntactic and procedural forms of these
-;;; abstractions are equivalent, since the optimizer consistently
-;;; integrates constants and small procedures. This will be true of
-;;; Guile as well, once we implement a proper inliner.
-
-
-;;; Implementation notes:
-
-;;; Objects with no standard print syntax, including objects containing
-;;; cycles and syntax object, are allowed in quoted data as long as they
-;;; are contained within a syntax form or produced by datum->syntax.
-;;; Such objects are never copied.
-
-;;; All identifiers that don't have macro definitions and are not bound
-;;; lexically are assumed to be global variables.
-
-;;; Top-level definitions of macro-introduced identifiers are allowed.
-;;; This may not be appropriate for implementations in which the
-;;; model is that bindings are created by definitions, as opposed to
-;;; one in which initial values are assigned by definitions.
-
-;;; Identifiers and syntax objects are implemented as vectors for
-;;; portability. As a result, it is possible to "forge" syntax objects.
-
-;;; The implementation of generate-temporaries assumes that it is
-;;; possible to generate globally unique symbols (gensyms).
-
-;;; The source location associated with incoming expressions is tracked
-;;; via the source-properties mechanism, a weak map from expression to
-;;; source information. At times the source is separated from the
-;;; expression; see the note below about "efficiency and confusion".
-
-
-;;; Bootstrapping:
-
-;;; When changing syntax-object representations, it is necessary to support
-;;; both old and new syntax-object representations in id-var-name. It
-;;; should be sufficient to recognize old representations and treat
-;;; them as not lexically bound.
-
-
-
-(eval-when (compile)
- (set-current-module (resolve-module '(guile))))
-
-(let ()
-;;; Private version of and-map that handles multiple lists.
-(define and-map*
- (lambda (f first . rest)
- (or (null? first)
- (if (null? rest)
- (let andmap ((first first))
- (let ((x (car first)) (first (cdr first)))
- (if (null? first)
- (f x)
- (and (f x) (andmap first)))))
- (let andmap ((first first) (rest rest))
- (let ((x (car first))
- (xr (map car rest))
- (first (cdr first))
- (rest (map cdr rest)))
- (if (null? first)
- (apply f x xr)
- (and (apply f x xr) (andmap first rest)))))))))
-
-(define-syntax define-expansion-constructors
- (lambda (x)
- (syntax-case x ()
- ((_)
- (let lp ((n 0) (out '()))
- (if (< n (vector-length %expanded-vtables))
- (lp (1+ n)
- (let* ((vtable (vector-ref %expanded-vtables n))
- (stem (struct-ref vtable (+ vtable-offset-user 0)))
- (fields (struct-ref vtable (+ vtable-offset-user 2)))
- (sfields (map (lambda (f) (datum->syntax x f)) fields))
- (ctor (datum->syntax x (symbol-append 'make- stem))))
- (cons #`(define (#,ctor #,@sfields)
- (make-struct (vector-ref %expanded-vtables #,n) 0
- #,@sfields))
- out)))
- #`(begin #,@(reverse out))))))))
-
-(define-syntax define-expansion-accessors
- (lambda (x)
- (syntax-case x ()
- ((_ stem field ...)
- (let lp ((n 0))
- (let ((vtable (vector-ref %expanded-vtables n))
- (stem (syntax->datum #'stem)))
- (if (eq? (struct-ref vtable (+ vtable-offset-user 0)) stem)
- #`(begin
- (define (#,(datum->syntax x (symbol-append stem '?)) x)
- (and (struct? x)
- (eq? (struct-vtable x)
- (vector-ref %expanded-vtables #,n))))
- #,@(map
- (lambda (f)
- (let ((get (datum->syntax x (symbol-append stem '- f)))
- (set (datum->syntax x (symbol-append 'set- stem '- f '!)))
- (idx (list-index (struct-ref vtable
- (+ vtable-offset-user 2))
- f)))
- #`(begin
- (define (#,get x)
- (struct-ref x #,idx))
- (define (#,set x v)
- (struct-set! x #,idx v)))))
- (syntax->datum #'(field ...))))
- (lp (1+ n)))))))))
-
-(define-syntax define-structure
- (lambda (x)
- (define construct-name
- (lambda (template-identifier . args)
- (datum->syntax
- template-identifier
- (string->symbol
- (apply string-append
- (map (lambda (x)
- (if (string? x)
- x
- (symbol->string (syntax->datum x))))
- args))))))
- (syntax-case x ()
- ((_ (name id1 ...))
- (and-map identifier? #'(name id1 ...))
- (with-syntax
- ((constructor (construct-name #'name "make-" #'name))
- (predicate (construct-name #'name #'name "?"))
- ((access ...)
- (map (lambda (x) (construct-name x #'name "-" x))
- #'(id1 ...)))
- ((assign ...)
- (map (lambda (x)
- (construct-name x "set-" #'name "-" x "!"))
- #'(id1 ...)))
- (structure-length
- (+ (length #'(id1 ...)) 1))
- ((index ...)
- (let f ((i 1) (ids #'(id1 ...)))
- (if (null? ids)
- '()
- (cons i (f (+ i 1) (cdr ids)))))))
- #'(begin
- (define constructor
- (lambda (id1 ...)
- (vector 'name id1 ... )))
- (define predicate
- (lambda (x)
- (and (vector? x)
- (= (vector-length x) structure-length)
- (eq? (vector-ref x 0) 'name))))
- (define access
- (lambda (x)
- (vector-ref x index)))
- ...
- (define assign
- (lambda (x update)
- (vector-set! x index update)))
- ...))))))
-
-(let ()
- (define-expansion-constructors)
- (define-expansion-accessors lambda meta)
-
-;;; hooks to nonportable run-time helpers
- (begin
- (define fx+ +)
- (define fx- -)
- (define fx= =)
- (define fx< <)
-
- (define top-level-eval-hook
- (lambda (x mod)
- (primitive-eval x)))
-
- (define local-eval-hook
- (lambda (x mod)
- (primitive-eval x)))
-
- (define-syntax gensym-hook
- (syntax-rules ()
- ((_) (gensym))))
-
- (define put-global-definition-hook
- (lambda (symbol type val)
- (module-define! (current-module)
- symbol
- (make-syntax-transformer symbol type val))))
-
- (define get-global-definition-hook
- (lambda (symbol module)
- (if (and (not module) (current-module))
- (warn "module system is booted, we should have a module" symbol))
- (let ((v (module-variable (if module
- (resolve-module (cdr module))
- (current-module))
- symbol)))
- (and v (variable-bound? v)
- (let ((val (variable-ref v)))
- (and (macro? val) (macro-type val)
- (cons (macro-type val)
- (macro-binding val)))))))))
-
-
- (define (decorate-source e s)
- (if (and (pair? e) s)
- (set-source-properties! e s))
- e)
-
- (define (maybe-name-value! name val)
- (if (lambda? val)
- (let ((meta (lambda-meta val)))
- (if (not (assq 'name meta))
- (set-lambda-meta! val (acons 'name name meta))))))
-
- ;;; output constructors
- (define build-void
- (lambda (source)
- (make-void source)))
-
- (define build-application
- (lambda (source fun-exp arg-exps)
- (make-application source fun-exp arg-exps)))
-
- (define build-conditional
- (lambda (source test-exp then-exp else-exp)
- (make-conditional source test-exp then-exp else-exp)))
-
- (define build-dynlet
- (lambda (source fluids vals body)
- (make-dynlet source fluids vals body)))
-
- (define build-lexical-reference
- (lambda (type source name var)
- (make-lexical-ref source name var)))
-
- (define build-lexical-assignment
- (lambda (source name var exp)
- (maybe-name-value! name exp)
- (make-lexical-set source name var exp)))
-
- (define (analyze-variable mod var modref-cont bare-cont)
- (if (not mod)
- (bare-cont var)
- (let ((kind (car mod))
- (mod (cdr mod)))
- (case kind
- ((public) (modref-cont mod var #t))
- ((private) (if (not (equal? mod (module-name (current-module))))
- (modref-cont mod var #f)
- (bare-cont var)))
- ((bare) (bare-cont var))
- ((hygiene) (if (and (not (equal? mod (module-name (current-module))))
- (module-variable (resolve-module mod) var))
- (modref-cont mod var #f)
- (bare-cont var)))
- (else (syntax-violation #f "bad module kind" var mod))))))
-
- (define build-global-reference
- (lambda (source var mod)
- (analyze-variable
- mod var
- (lambda (mod var public?)
- (make-module-ref source mod var public?))
- (lambda (var)
- (make-toplevel-ref source var)))))
-
- (define build-global-assignment
- (lambda (source var exp mod)
- (maybe-name-value! var exp)
- (analyze-variable
- mod var
- (lambda (mod var public?)
- (make-module-set source mod var public? exp))
- (lambda (var)
- (make-toplevel-set source var exp)))))
-
- (define build-global-definition
- (lambda (source var exp)
- (maybe-name-value! var exp)
- (make-toplevel-define source var exp)))
-
- (define build-simple-lambda
- (lambda (src req rest vars meta exp)
- (make-lambda src
- meta
- ;; hah, a case in which kwargs would be nice.
- (make-lambda-case
- ;; src req opt rest kw inits vars body else
- src req #f rest #f '() vars exp #f))))
-
- (define build-case-lambda
- (lambda (src meta body)
- (make-lambda src meta body)))
-
- (define build-lambda-case
- ;; req := (name ...)
- ;; opt := (name ...) | #f
- ;; rest := name | #f
- ;; kw := (allow-other-keys? (keyword name var) ...) | #f
- ;; inits: (init ...)
- ;; vars: (sym ...)
- ;; vars map to named arguments in the following order:
- ;; required, optional (positional), rest, keyword.
- ;; the body of a lambda: anything, already expanded
- ;; else: lambda-case | #f
- (lambda (src req opt rest kw inits vars body else-case)
- (make-lambda-case src req opt rest kw inits vars body else-case)))
-
- (define build-primref
- (lambda (src name)
- (if (equal? (module-name (current-module)) '(guile))
- (make-toplevel-ref src name)
- (make-module-ref src '(guile) name #f))))
-
- (define (build-data src exp)
- (make-const src exp))
-
- (define build-sequence
- (lambda (src exps)
- (if (null? (cdr exps))
- (car exps)
- (make-sequence src exps))))
-
- (define build-let
- (lambda (src ids vars val-exps body-exp)
- (for-each maybe-name-value! ids val-exps)
- (if (null? vars)
- body-exp
- (make-let src ids vars val-exps body-exp))))
-
- (define build-named-let
- (lambda (src ids vars val-exps body-exp)
- (let ((f (car vars))
- (f-name (car ids))
- (vars (cdr vars))
- (ids (cdr ids)))
- (let ((proc (build-simple-lambda src ids #f vars '() body-exp)))
- (maybe-name-value! f-name proc)
- (for-each maybe-name-value! ids val-exps)
- (make-letrec
- src #f
- (list f-name) (list f) (list proc)
- (build-application src (build-lexical-reference 'fun src f-name f)
- val-exps))))))
-
- (define build-letrec
- (lambda (src in-order? ids vars val-exps body-exp)
- (if (null? vars)
- body-exp
- (begin
- (for-each maybe-name-value! ids val-exps)
- (make-letrec src in-order? ids vars val-exps body-exp)))))
-
-
- ;; FIXME: use a faster gensym
- (define-syntax build-lexical-var
- (syntax-rules ()
- ((_ src id) (gensym (string-append (symbol->string id) " ")))))
-
- (define-structure (syntax-object expression wrap module))
-
- (define-syntax no-source (identifier-syntax #f))
-
- (define source-annotation
- (lambda (x)
- (cond
- ((syntax-object? x)
- (source-annotation (syntax-object-expression x)))
- ((pair? x) (let ((props (source-properties x)))
- (if (pair? props)
- props
- #f)))
- (else #f))))
-
- (define-syntax arg-check
- (syntax-rules ()
- ((_ pred? e who)
- (let ((x e))
- (if (not (pred? x)) (syntax-violation who "invalid argument" x))))))
-
-;;; compile-time environments
-
-;;; wrap and environment comprise two level mapping.
-;;; wrap : id --> label
-;;; env : label --> <element>
-
-;;; environments are represented in two parts: a lexical part and a global
-;;; part. The lexical part is a simple list of associations from labels
-;;; to bindings. The global part is implemented by
-;;; {put,get}-global-definition-hook and associates symbols with
-;;; bindings.
-
-;;; global (assumed global variable) and displaced-lexical (see below)
-;;; do not show up in any environment; instead, they are fabricated by
-;;; lookup when it finds no other bindings.
-
-;;; <environment> ::= ((<label> . <binding>)*)
-
-;;; identifier bindings include a type and a value
-
-;;; <binding> ::= (macro . <procedure>) macros
-;;; (core . <procedure>) core forms
-;;; (module-ref . <procedure>) @ or @@
-;;; (begin) begin
-;;; (define) define
-;;; (define-syntax) define-syntax
-;;; (local-syntax . rec?) let-syntax/letrec-syntax
-;;; (eval-when) eval-when
-;;; #'. (<var> . <level>) pattern variables
-;;; (global) assumed global variable
-;;; (lexical . <var>) lexical variables
-;;; (displaced-lexical) displaced lexicals
-;;; <level> ::= <nonnegative integer>
-;;; <var> ::= variable returned by build-lexical-var
-
-;;; a macro is a user-defined syntactic-form. a core is a system-defined
-;;; syntactic form. begin, define, define-syntax, and eval-when are
-;;; treated specially since they are sensitive to whether the form is
-;;; at top-level and (except for eval-when) can denote valid internal
-;;; definitions.
-
-;;; a pattern variable is a variable introduced by syntax-case and can
-;;; be referenced only within a syntax form.
-
-;;; any identifier for which no top-level syntax definition or local
-;;; binding of any kind has been seen is assumed to be a global
-;;; variable.
-
-;;; a lexical variable is a lambda- or letrec-bound variable.
-
-;;; a displaced-lexical identifier is a lexical identifier removed from
-;;; it's scope by the return of a syntax object containing the identifier.
-;;; a displaced lexical can also appear when a letrec-syntax-bound
-;;; keyword is referenced on the rhs of one of the letrec-syntax clauses.
-;;; a displaced lexical should never occur with properly written macros.
-
- (define-syntax make-binding
- (syntax-rules (quote)
- ((_ type value) (cons type value))
- ((_ 'type) '(type))
- ((_ type) (cons type '()))))
- (define binding-type car)
- (define binding-value cdr)
-
- (define-syntax null-env (identifier-syntax '()))
-
- (define extend-env
- (lambda (labels bindings r)
- (if (null? labels)
- r
- (extend-env (cdr labels) (cdr bindings)
- (cons (cons (car labels) (car bindings)) r)))))
-
- (define extend-var-env
- ;; variant of extend-env that forms "lexical" binding
- (lambda (labels vars r)
- (if (null? labels)
- r
- (extend-var-env (cdr labels) (cdr vars)
- (cons (cons (car labels) (make-binding 'lexical (car vars))) r)))))
-
-;;; we use a "macros only" environment in expansion of local macro
-;;; definitions so that their definitions can use local macros without
-;;; attempting to use other lexical identifiers.
- (define macros-only-env
- (lambda (r)
- (if (null? r)
- '()
- (let ((a (car r)))
- (if (eq? (cadr a) 'macro)
- (cons a (macros-only-env (cdr r)))
- (macros-only-env (cdr r)))))))
-
- (define lookup
- ;; x may be a label or a symbol
- ;; although symbols are usually global, we check the environment first
- ;; anyway because a temporary binding may have been established by
- ;; fluid-let-syntax
- (lambda (x r mod)
- (cond
- ((assq x r) => cdr)
- ((symbol? x)
- (or (get-global-definition-hook x mod) (make-binding 'global)))
- (else (make-binding 'displaced-lexical)))))
-
- (define global-extend
- (lambda (type sym val)
- (put-global-definition-hook sym type val)))
-
-
-;;; Conceptually, identifiers are always syntax objects. Internally,
-;;; however, the wrap is sometimes maintained separately (a source of
-;;; efficiency and confusion), so that symbols are also considered
-;;; identifiers by id?. Externally, they are always wrapped.
-
- (define nonsymbol-id?
- (lambda (x)
- (and (syntax-object? x)
- (symbol? (syntax-object-expression x)))))
-
- (define id?
- (lambda (x)
- (cond
- ((symbol? x) #t)
- ((syntax-object? x) (symbol? (syntax-object-expression x)))
- (else #f))))
-
- (define-syntax id-sym-name
- (syntax-rules ()
- ((_ e)
- (let ((x e))
- (if (syntax-object? x)
- (syntax-object-expression x)
- x)))))
-
- (define id-sym-name&marks
- (lambda (x w)
- (if (syntax-object? x)
- (values
- (syntax-object-expression x)
- (join-marks (wrap-marks w) (wrap-marks (syntax-object-wrap x))))
- (values x (wrap-marks w)))))
-
-;;; syntax object wraps
-
-;;; <wrap> ::= ((<mark> ...) . (<subst> ...))
-;;; <subst> ::= <shift> | <subs>
-;;; <subs> ::= #(<old name> <label> (<mark> ...))
-;;; <shift> ::= positive fixnum
-
- (define make-wrap cons)
- (define wrap-marks car)
- (define wrap-subst cdr)
-
- (define-syntax subst-rename? (identifier-syntax vector?))
- (define-syntax rename-old (syntax-rules () ((_ x) (vector-ref x 0))))
- (define-syntax rename-new (syntax-rules () ((_ x) (vector-ref x 1))))
- (define-syntax rename-marks (syntax-rules () ((_ x) (vector-ref x 2))))
- (define-syntax make-rename
- (syntax-rules ()
- ((_ old new marks) (vector old new marks))))
-
-;;; labels must be comparable with "eq?", have read-write invariance,
-;;; and distinct from symbols.
- (define gen-label
- (lambda () (symbol->string (gensym "i"))))
-
- (define gen-labels
- (lambda (ls)
- (if (null? ls)
- '()
- (cons (gen-label) (gen-labels (cdr ls))))))
-
- (define-structure (ribcage symnames marks labels))
-
- (define-syntax empty-wrap (identifier-syntax '(())))
-
- (define-syntax top-wrap (identifier-syntax '((top))))
-
- (define-syntax top-marked?
- (syntax-rules ()
- ((_ w) (memq 'top (wrap-marks w)))))
-
-;;; Marks must be comparable with "eq?" and distinct from pairs and
-;;; the symbol top. We do not use integers so that marks will remain
-;;; unique even across file compiles.
-
- (define-syntax the-anti-mark (identifier-syntax #f))
-
- (define anti-mark
- (lambda (w)
- (make-wrap (cons the-anti-mark (wrap-marks w))
- (cons 'shift (wrap-subst w)))))
-
- (define-syntax new-mark
- (syntax-rules ()
- ((_) (gensym "m"))))
-
-;;; make-empty-ribcage and extend-ribcage maintain list-based ribcages for
-;;; internal definitions, in which the ribcages are built incrementally
- (define-syntax make-empty-ribcage
- (syntax-rules ()
- ((_) (make-ribcage '() '() '()))))
-
- (define extend-ribcage!
- ;; must receive ids with complete wraps
- (lambda (ribcage id label)
- (set-ribcage-symnames! ribcage
- (cons (syntax-object-expression id)
- (ribcage-symnames ribcage)))
- (set-ribcage-marks! ribcage
- (cons (wrap-marks (syntax-object-wrap id))
- (ribcage-marks ribcage)))
- (set-ribcage-labels! ribcage
- (cons label (ribcage-labels ribcage)))))
-
-;;; make-binding-wrap creates vector-based ribcages
- (define make-binding-wrap
- (lambda (ids labels w)
- (if (null? ids)
- w
- (make-wrap
- (wrap-marks w)
- (cons
- (let ((labelvec (list->vector labels)))
- (let ((n (vector-length labelvec)))
- (let ((symnamevec (make-vector n)) (marksvec (make-vector n)))
- (let f ((ids ids) (i 0))
- (if (not (null? ids))
- (call-with-values
- (lambda () (id-sym-name&marks (car ids) w))
- (lambda (symname marks)
- (vector-set! symnamevec i symname)
- (vector-set! marksvec i marks)
- (f (cdr ids) (fx+ i 1))))))
- (make-ribcage symnamevec marksvec labelvec))))
- (wrap-subst w))))))
-
- (define smart-append
- (lambda (m1 m2)
- (if (null? m2)
- m1
- (append m1 m2))))
-
- (define join-wraps
- (lambda (w1 w2)
- (let ((m1 (wrap-marks w1)) (s1 (wrap-subst w1)))
- (if (null? m1)
- (if (null? s1)
- w2
- (make-wrap
- (wrap-marks w2)
- (smart-append s1 (wrap-subst w2))))
- (make-wrap
- (smart-append m1 (wrap-marks w2))
- (smart-append s1 (wrap-subst w2)))))))
-
- (define join-marks
- (lambda (m1 m2)
- (smart-append m1 m2)))
-
- (define same-marks?
- (lambda (x y)
- (or (eq? x y)
- (and (not (null? x))
- (not (null? y))
- (eq? (car x) (car y))
- (same-marks? (cdr x) (cdr y))))))
-
- (define id-var-name
- (lambda (id w)
- (define-syntax first
- (syntax-rules ()
- ((_ e) (call-with-values (lambda () e) (lambda (x . ignore) x)))))
- (define search
- (lambda (sym subst marks)
- (if (null? subst)
- (values #f marks)
- (let ((fst (car subst)))
- (if (eq? fst 'shift)
- (search sym (cdr subst) (cdr marks))
- (let ((symnames (ribcage-symnames fst)))
- (if (vector? symnames)
- (search-vector-rib sym subst marks symnames fst)
- (search-list-rib sym subst marks symnames fst))))))))
- (define search-list-rib
- (lambda (sym subst marks symnames ribcage)
- (let f ((symnames symnames) (i 0))
- (cond
- ((null? symnames) (search sym (cdr subst) marks))
- ((and (eq? (car symnames) sym)
- (same-marks? marks (list-ref (ribcage-marks ribcage) i)))
- (values (list-ref (ribcage-labels ribcage) i) marks))
- (else (f (cdr symnames) (fx+ i 1)))))))
- (define search-vector-rib
- (lambda (sym subst marks symnames ribcage)
- (let ((n (vector-length symnames)))
- (let f ((i 0))
- (cond
- ((fx= i n) (search sym (cdr subst) marks))
- ((and (eq? (vector-ref symnames i) sym)
- (same-marks? marks (vector-ref (ribcage-marks ribcage) i)))
- (values (vector-ref (ribcage-labels ribcage) i) marks))
- (else (f (fx+ i 1))))))))
- (cond
- ((symbol? id)
- (or (first (search id (wrap-subst w) (wrap-marks w))) id))
- ((syntax-object? id)
- (let ((id (syntax-object-expression id))
- (w1 (syntax-object-wrap id)))
- (let ((marks (join-marks (wrap-marks w) (wrap-marks w1))))
- (call-with-values (lambda () (search id (wrap-subst w) marks))
- (lambda (new-id marks)
- (or new-id
- (first (search id (wrap-subst w1) marks))
- id))))))
- (else (syntax-violation 'id-var-name "invalid id" id)))))
-
-;;; free-id=? must be passed fully wrapped ids since (free-id=? x y)
-;;; may be true even if (free-id=? (wrap x w) (wrap y w)) is not.
-
- (define free-id=?
- (lambda (i j)
- (and (eq? (id-sym-name i) (id-sym-name j)) ; accelerator
- (eq? (id-var-name i empty-wrap) (id-var-name j empty-wrap)))))
-
-;;; bound-id=? may be passed unwrapped (or partially wrapped) ids as
-;;; long as the missing portion of the wrap is common to both of the ids
-;;; since (bound-id=? x y) iff (bound-id=? (wrap x w) (wrap y w))
-
- (define bound-id=?
- (lambda (i j)
- (if (and (syntax-object? i) (syntax-object? j))
- (and (eq? (syntax-object-expression i)
- (syntax-object-expression j))
- (same-marks? (wrap-marks (syntax-object-wrap i))
- (wrap-marks (syntax-object-wrap j))))
- (eq? i j))))
-
-;;; "valid-bound-ids?" returns #t if it receives a list of distinct ids.
-;;; valid-bound-ids? may be passed unwrapped (or partially wrapped) ids
-;;; as long as the missing portion of the wrap is common to all of the
-;;; ids.
-
- (define valid-bound-ids?
- (lambda (ids)
- (and (let all-ids? ((ids ids))
- (or (null? ids)
- (and (id? (car ids))
- (all-ids? (cdr ids)))))
- (distinct-bound-ids? ids))))
-
-;;; distinct-bound-ids? expects a list of ids and returns #t if there are
-;;; no duplicates. It is quadratic on the length of the id list; long
-;;; lists could be sorted to make it more efficient. distinct-bound-ids?
-;;; may be passed unwrapped (or partially wrapped) ids as long as the
-;;; missing portion of the wrap is common to all of the ids.
-
- (define distinct-bound-ids?
- (lambda (ids)
- (let distinct? ((ids ids))
- (or (null? ids)
- (and (not (bound-id-member? (car ids) (cdr ids)))
- (distinct? (cdr ids)))))))
-
- (define bound-id-member?
- (lambda (x list)
- (and (not (null? list))
- (or (bound-id=? x (car list))
- (bound-id-member? x (cdr list))))))
-
-;;; wrapping expressions and identifiers
-
- (define wrap
- (lambda (x w defmod)
- (cond
- ((and (null? (wrap-marks w)) (null? (wrap-subst w))) x)
- ((syntax-object? x)
- (make-syntax-object
- (syntax-object-expression x)
- (join-wraps w (syntax-object-wrap x))
- (syntax-object-module x)))
- ((null? x) x)
- (else (make-syntax-object x w defmod)))))
-
- (define source-wrap
- (lambda (x w s defmod)
- (wrap (decorate-source x s) w defmod)))
-
-;;; expanding
-
- (define chi-sequence
- (lambda (body r w s mod)
- (build-sequence s
- (let dobody ((body body) (r r) (w w) (mod mod))
- (if (null? body)
- '()
- (let ((first (chi (car body) r w mod)))
- (cons first (dobody (cdr body) r w mod))))))))
-
- (define chi-top-sequence
- (lambda (body r w s m esew mod)
- (build-sequence s
- (let dobody ((body body) (r r) (w w) (m m) (esew esew)
- (mod mod) (out '()))
- (if (null? body)
- (reverse out)
- (dobody (cdr body) r w m esew mod
- (cons (chi-top (car body) r w m esew mod) out)))))))
-
- (define chi-install-global
- (lambda (name e)
- (build-global-definition
- no-source
- name
- (build-application
- no-source
- (build-primref no-source 'make-syntax-transformer)
- (list (build-data no-source name)
- (build-data no-source 'macro)
- e)))))
-
- (define chi-when-list
- (lambda (e when-list w)
- ;; when-list is syntax'd version of list of situations
- (let f ((when-list when-list) (situations '()))
- (if (null? when-list)
- situations
- (f (cdr when-list)
- (cons (let ((x (car when-list)))
- (cond
- ((free-id=? x #'compile) 'compile)
- ((free-id=? x #'load) 'load)
- ((free-id=? x #'eval) 'eval)
- ((free-id=? x #'expand) 'expand)
- (else (syntax-violation 'eval-when
- "invalid situation"
- e (wrap x w #f)))))
- situations))))))
-
-;;; syntax-type returns six values: type, value, e, w, s, and mod. The
-;;; first two are described in the table below.
-;;;
-;;; type value explanation
-;;; -------------------------------------------------------------------
-;;; core procedure core singleton
-;;; core-form procedure core form
-;;; module-ref procedure @ or @@ singleton
-;;; lexical name lexical variable reference
-;;; global name global variable reference
-;;; begin none begin keyword
-;;; define none define keyword
-;;; define-syntax none define-syntax keyword
-;;; local-syntax rec? letrec-syntax/let-syntax keyword
-;;; eval-when none eval-when keyword
-;;; syntax level pattern variable
-;;; displaced-lexical none displaced lexical identifier
-;;; lexical-call name call to lexical variable
-;;; global-call name call to global variable
-;;; call none any other call
-;;; begin-form none begin expression
-;;; define-form id variable definition
-;;; define-syntax-form id syntax definition
-;;; local-syntax-form rec? syntax definition
-;;; eval-when-form none eval-when form
-;;; constant none self-evaluating datum
-;;; other none anything else
-;;;
-;;; For define-form and define-syntax-form, e is the rhs expression.
-;;; For all others, e is the entire form. w is the wrap for e.
-;;; s is the source for the entire form. mod is the module for e.
-;;;
-;;; syntax-type expands macros and unwraps as necessary to get to
-;;; one of the forms above. It also parses define and define-syntax
-;;; forms, although perhaps this should be done by the consumer.
-
- (define syntax-type
- (lambda (e r w s rib mod for-car?)
- (cond
- ((symbol? e)
- (let* ((n (id-var-name e w))
- (b (lookup n r mod))
- (type (binding-type b)))
- (case type
- ((lexical) (values type (binding-value b) e w s mod))
- ((global) (values type n e w s mod))
- ((macro)
- (if for-car?
- (values type (binding-value b) e w s mod)
- (syntax-type (chi-macro (binding-value b) e r w s rib mod)
- r empty-wrap s rib mod #f)))
- (else (values type (binding-value b) e w s mod)))))
- ((pair? e)
- (let ((first (car e)))
- (call-with-values
- (lambda () (syntax-type first r w s rib mod #t))
- (lambda (ftype fval fe fw fs fmod)
- (case ftype
- ((lexical)
- (values 'lexical-call fval e w s mod))
- ((global)
- ;; If we got here via an (@@ ...) expansion, we need to
- ;; make sure the fmod information is propagated back
- ;; correctly -- hence this consing.
- (values 'global-call (make-syntax-object fval w fmod)
- e w s mod))
- ((macro)
- (syntax-type (chi-macro fval e r w s rib mod)
- r empty-wrap s rib mod for-car?))
- ((module-ref)
- (call-with-values (lambda () (fval e r w))
- (lambda (e r w s mod)
- (syntax-type e r w s rib mod for-car?))))
- ((core)
- (values 'core-form fval e w s mod))
- ((local-syntax)
- (values 'local-syntax-form fval e w s mod))
- ((begin)
- (values 'begin-form #f e w s mod))
- ((eval-when)
- (values 'eval-when-form #f e w s mod))
- ((define)
- (syntax-case e ()
- ((_ name val)
- (id? #'name)
- (values 'define-form #'name #'val w s mod))
- ((_ (name . args) e1 e2 ...)
- (and (id? #'name)
- (valid-bound-ids? (lambda-var-list #'args)))
- ;; need lambda here...
- (values 'define-form (wrap #'name w mod)
- (decorate-source
- (cons #'lambda (wrap #'(args e1 e2 ...) w mod))
- s)
- empty-wrap s mod))
- ((_ name)
- (id? #'name)
- (values 'define-form (wrap #'name w mod)
- #'(if #f #f)
- empty-wrap s mod))))
- ((define-syntax)
- (syntax-case e ()
- ((_ name val)
- (id? #'name)
- (values 'define-syntax-form #'name
- #'val w s mod))))
- (else
- (values 'call #f e w s mod)))))))
- ((syntax-object? e)
- (syntax-type (syntax-object-expression e)
- r
- (join-wraps w (syntax-object-wrap e))
- (or (source-annotation e) s) rib
- (or (syntax-object-module e) mod) for-car?))
- ((self-evaluating? e) (values 'constant #f e w s mod))
- (else (values 'other #f e w s mod)))))
-
- (define chi-top
- (lambda (e r w m esew mod)
- (define-syntax eval-if-c&e
- (syntax-rules ()
- ((_ m e mod)
- (let ((x e))
- (if (eq? m 'c&e) (top-level-eval-hook x mod))
- x))))
- (call-with-values
- (lambda () (syntax-type e r w (source-annotation e) #f mod #f))
- (lambda (type value e w s mod)
- (case type
- ((begin-form)
- (syntax-case e ()
- ((_) (chi-void))
- ((_ e1 e2 ...)
- (chi-top-sequence #'(e1 e2 ...) r w s m esew mod))))
- ((local-syntax-form)
- (chi-local-syntax value e r w s mod
- (lambda (body r w s mod)
- (chi-top-sequence body r w s m esew mod))))
- ((eval-when-form)
- (syntax-case e ()
- ((_ (x ...) e1 e2 ...)
- (let ((when-list (chi-when-list e #'(x ...) w))
- (body #'(e1 e2 ...)))
- (cond
- ((eq? m 'e)
- (if (memq 'eval when-list)
- (chi-top-sequence body r w s
- (if (memq 'expand when-list) 'c&e 'e)
- '(eval)
- mod)
- (begin
- (if (memq 'expand when-list)
- (top-level-eval-hook
- (chi-top-sequence body r w s 'e '(eval) mod)
- mod))
- (chi-void))))
- ((memq 'load when-list)
- (if (or (memq 'compile when-list)
- (memq 'expand when-list)
- (and (eq? m 'c&e) (memq 'eval when-list)))
- (chi-top-sequence body r w s 'c&e '(compile load) mod)
- (if (memq m '(c c&e))
- (chi-top-sequence body r w s 'c '(load) mod)
- (chi-void))))
- ((or (memq 'compile when-list)
- (memq 'expand when-list)
- (and (eq? m 'c&e) (memq 'eval when-list)))
- (top-level-eval-hook
- (chi-top-sequence body r w s 'e '(eval) mod)
- mod)
- (chi-void))
- (else (chi-void)))))))
- ((define-syntax-form)
- (let ((n (id-var-name value w)) (r (macros-only-env r)))
- (case m
- ((c)
- (if (memq 'compile esew)
- (let ((e (chi-install-global n (chi e r w mod))))
- (top-level-eval-hook e mod)
- (if (memq 'load esew) e (chi-void)))
- (if (memq 'load esew)
- (chi-install-global n (chi e r w mod))
- (chi-void))))
- ((c&e)
- (let ((e (chi-install-global n (chi e r w mod))))
- (top-level-eval-hook e mod)
- e))
- (else
- (if (memq 'eval esew)
- (top-level-eval-hook
- (chi-install-global n (chi e r w mod))
- mod))
- (chi-void)))))
- ((define-form)
- (let* ((n (id-var-name value w))
- ;; Lookup the name in the module of the define form.
- (type (binding-type (lookup n r mod))))
- (case type
- ((global core macro module-ref)
- ;; affect compile-time environment (once we have booted)
- (if (and (memq m '(c c&e))
- (not (module-local-variable (current-module) n))
- (current-module))
- (let ((old (module-variable (current-module) n)))
- ;; use value of the same-named imported variable, if
- ;; any
- (module-define! (current-module) n
- (if (variable? old)
- (variable-ref old)
- #f))))
- (eval-if-c&e m
- (build-global-definition s n (chi e r w mod))
- mod))
- ((displaced-lexical)
- (syntax-violation #f "identifier out of context"
- e (wrap value w mod)))
- (else
- (syntax-violation #f "cannot define keyword at top level"
- e (wrap value w mod))))))
- (else (eval-if-c&e m (chi-expr type value e r w s mod) mod)))))))
-
- (define chi
- (lambda (e r w mod)
- (call-with-values
- (lambda () (syntax-type e r w (source-annotation e) #f mod #f))
- (lambda (type value e w s mod)
- (chi-expr type value e r w s mod)))))
-
- (define chi-expr
- (lambda (type value e r w s mod)
- (case type
- ((lexical)
- (build-lexical-reference 'value s e value))
- ((core core-form)
- ;; apply transformer
- (value e r w s mod))
- ((module-ref)
- (call-with-values (lambda () (value e r w))
- (lambda (e r w s mod)
- (chi e r w mod))))
- ((lexical-call)
- (chi-application
- (let ((id (car e)))
- (build-lexical-reference 'fun (source-annotation id)
- (if (syntax-object? id)
- (syntax->datum id)
- id)
- value))
- e r w s mod))
- ((global-call)
- (chi-application
- (build-global-reference (source-annotation (car e))
- (if (syntax-object? value)
- (syntax-object-expression value)
- value)
- (if (syntax-object? value)
- (syntax-object-module value)
- mod))
- e r w s mod))
- ((constant) (build-data s (strip (source-wrap e w s mod) empty-wrap)))
- ((global) (build-global-reference s value mod))
- ((call) (chi-application (chi (car e) r w mod) e r w s mod))
- ((begin-form)
- (syntax-case e ()
- ((_ e1 e2 ...) (chi-sequence #'(e1 e2 ...) r w s mod))))
- ((local-syntax-form)
- (chi-local-syntax value e r w s mod chi-sequence))
- ((eval-when-form)
- (syntax-case e ()
- ((_ (x ...) e1 e2 ...)
- (let ((when-list (chi-when-list e #'(x ...) w)))
- (if (memq 'eval when-list)
- (chi-sequence #'(e1 e2 ...) r w s mod)
- (chi-void))))))
- ((define-form define-syntax-form)
- (syntax-violation #f "definition in expression context"
- e (wrap value w mod)))
- ((syntax)
- (syntax-violation #f "reference to pattern variable outside syntax form"
- (source-wrap e w s mod)))
- ((displaced-lexical)
- (syntax-violation #f "reference to identifier outside its scope"
- (source-wrap e w s mod)))
- (else (syntax-violation #f "unexpected syntax"
- (source-wrap e w s mod))))))
-
- (define chi-application
- (lambda (x e r w s mod)
- (syntax-case e ()
- ((e0 e1 ...)
- (build-application s x
- (map (lambda (e) (chi e r w mod)) #'(e1 ...)))))))
-
- ;; (What follows is my interpretation of what's going on here -- Andy)
- ;;
- ;; A macro takes an expression, a tree, the leaves of which are identifiers
- ;; and datums. Identifiers are symbols along with a wrap and a module. For
- ;; efficiency, subtrees that share wraps and modules may be grouped as one
- ;; syntax object.
- ;;
- ;; Going into the expansion, the expression is given an anti-mark, which
- ;; logically propagates to all leaves. Then, in the new expression returned
- ;; from the transfomer, if we see an expression with an anti-mark, we know it
- ;; pertains to the original expression; conversely, expressions without the
- ;; anti-mark are known to be introduced by the transformer.
- ;;
- ;; OK, good until now. We know this algorithm does lexical scoping
- ;; appropriately because it's widely known in the literature, and psyntax is
- ;; widely used. But what about modules? Here we're on our own. What we do is
- ;; to mark the module of expressions produced by a macro as pertaining to the
- ;; module that was current when the macro was defined -- that is, free
- ;; identifiers introduced by a macro are scoped in the macro's module, not in
- ;; the expansion's module. Seems to work well.
- ;;
- ;; The only wrinkle is when we want a macro to expand to code in another
- ;; module, as is the case for the r6rs `library' form -- the body expressions
- ;; should be scoped relative the the new module, the one defined by the macro.
- ;; For that, use `(@@ mod-name body)'.
- ;;
- ;; Part of the macro output will be from the site of the macro use and part
- ;; from the macro definition. We allow source information from the macro use
- ;; to pass through, but we annotate the parts coming from the macro with the
- ;; source location information corresponding to the macro use. It would be
- ;; really nice if we could also annotate introduced expressions with the
- ;; locations corresponding to the macro definition, but that is not yet
- ;; possible.
- (define chi-macro
- (lambda (p e r w s rib mod)
- (define rebuild-macro-output
- (lambda (x m)
- (cond ((pair? x)
- (decorate-source
- (cons (rebuild-macro-output (car x) m)
- (rebuild-macro-output (cdr x) m))
- s))
- ((syntax-object? x)
- (let ((w (syntax-object-wrap x)))
- (let ((ms (wrap-marks w)) (s (wrap-subst w)))
- (if (and (pair? ms) (eq? (car ms) the-anti-mark))
- ;; output is from original text
- (make-syntax-object
- (syntax-object-expression x)
- (make-wrap (cdr ms) (if rib (cons rib (cdr s)) (cdr s)))
- (syntax-object-module x))
- ;; output introduced by macro
- (make-syntax-object
- (decorate-source (syntax-object-expression x) s)
- (make-wrap (cons m ms)
- (if rib
- (cons rib (cons 'shift s))
- (cons 'shift s)))
- (syntax-object-module x))))))
-
- ((vector? x)
- (let* ((n (vector-length x))
- (v (decorate-source (make-vector n) x)))
- (do ((i 0 (fx+ i 1)))
- ((fx= i n) v)
- (vector-set! v i
- (rebuild-macro-output (vector-ref x i) m)))))
- ((symbol? x)
- (syntax-violation #f "encountered raw symbol in macro output"
- (source-wrap e w (wrap-subst w) mod) x))
- (else (decorate-source x s)))))
- (rebuild-macro-output (p (source-wrap e (anti-mark w) s mod))
- (new-mark))))
-
- (define chi-body
- ;; In processing the forms of the body, we create a new, empty wrap.
- ;; This wrap is augmented (destructively) each time we discover that
- ;; the next form is a definition. This is done:
- ;;
- ;; (1) to allow the first nondefinition form to be a call to
- ;; one of the defined ids even if the id previously denoted a
- ;; definition keyword or keyword for a macro expanding into a
- ;; definition;
- ;; (2) to prevent subsequent definition forms (but unfortunately
- ;; not earlier ones) and the first nondefinition form from
- ;; confusing one of the bound identifiers for an auxiliary
- ;; keyword; and
- ;; (3) so that we do not need to restart the expansion of the
- ;; first nondefinition form, which is problematic anyway
- ;; since it might be the first element of a begin that we
- ;; have just spliced into the body (meaning if we restarted,
- ;; we'd really need to restart with the begin or the macro
- ;; call that expanded into the begin, and we'd have to give
- ;; up allowing (begin <defn>+ <expr>+), which is itself
- ;; problematic since we don't know if a begin contains only
- ;; definitions until we've expanded it).
- ;;
- ;; Before processing the body, we also create a new environment
- ;; containing a placeholder for the bindings we will add later and
- ;; associate this environment with each form. In processing a
- ;; let-syntax or letrec-syntax, the associated environment may be
- ;; augmented with local keyword bindings, so the environment may
- ;; be different for different forms in the body. Once we have
- ;; gathered up all of the definitions, we evaluate the transformer
- ;; expressions and splice into r at the placeholder the new variable
- ;; and keyword bindings. This allows let-syntax or letrec-syntax
- ;; forms local to a portion or all of the body to shadow the
- ;; definition bindings.
- ;;
- ;; Subforms of a begin, let-syntax, or letrec-syntax are spliced
- ;; into the body.
- ;;
- ;; outer-form is fully wrapped w/source
- (lambda (body outer-form r w mod)
- (let* ((r (cons '("placeholder" . (placeholder)) r))
- (ribcage (make-empty-ribcage))
- (w (make-wrap (wrap-marks w) (cons ribcage (wrap-subst w)))))
- (let parse ((body (map (lambda (x) (cons r (wrap x w mod))) body))
- (ids '()) (labels '())
- (var-ids '()) (vars '()) (vals '()) (bindings '()))
- (if (null? body)
- (syntax-violation #f "no expressions in body" outer-form)
- (let ((e (cdar body)) (er (caar body)))
- (call-with-values
- (lambda () (syntax-type e er empty-wrap (source-annotation er) ribcage mod #f))
- (lambda (type value e w s mod)
- (case type
- ((define-form)
- (let ((id (wrap value w mod)) (label (gen-label)))
- (let ((var (gen-var id)))
- (extend-ribcage! ribcage id label)
- (parse (cdr body)
- (cons id ids) (cons label labels)
- (cons id var-ids)
- (cons var vars) (cons (cons er (wrap e w mod)) vals)
- (cons (make-binding 'lexical var) bindings)))))
- ((define-syntax-form)
- (let ((id (wrap value w mod)) (label (gen-label)))
- (extend-ribcage! ribcage id label)
- (parse (cdr body)
- (cons id ids) (cons label labels)
- var-ids vars vals
- (cons (make-binding 'macro (cons er (wrap e w mod)))
- bindings))))
- ((begin-form)
- (syntax-case e ()
- ((_ e1 ...)
- (parse (let f ((forms #'(e1 ...)))
- (if (null? forms)
- (cdr body)
- (cons (cons er (wrap (car forms) w mod))
- (f (cdr forms)))))
- ids labels var-ids vars vals bindings))))
- ((local-syntax-form)
- (chi-local-syntax value e er w s mod
- (lambda (forms er w s mod)
- (parse (let f ((forms forms))
- (if (null? forms)
- (cdr body)
- (cons (cons er (wrap (car forms) w mod))
- (f (cdr forms)))))
- ids labels var-ids vars vals bindings))))
- (else ; found a non-definition
- (if (null? ids)
- (build-sequence no-source
- (map (lambda (x)
- (chi (cdr x) (car x) empty-wrap mod))
- (cons (cons er (source-wrap e w s mod))
- (cdr body))))
- (begin
- (if (not (valid-bound-ids? ids))
- (syntax-violation
- #f "invalid or duplicate identifier in definition"
- outer-form))
- (let loop ((bs bindings) (er-cache #f) (r-cache #f))
- (if (not (null? bs))
- (let* ((b (car bs)))
- (if (eq? (car b) 'macro)
- (let* ((er (cadr b))
- (r-cache
- (if (eq? er er-cache)
- r-cache
- (macros-only-env er))))
- (set-cdr! b
- (eval-local-transformer
- (chi (cddr b) r-cache empty-wrap mod)
- mod))
- (loop (cdr bs) er r-cache))
- (loop (cdr bs) er-cache r-cache)))))
- (set-cdr! r (extend-env labels bindings (cdr r)))
- (build-letrec no-source #t
- (reverse (map syntax->datum var-ids))
- (reverse vars)
- (map (lambda (x)
- (chi (cdr x) (car x) empty-wrap mod))
- (reverse vals))
- (build-sequence no-source
- (map (lambda (x)
- (chi (cdr x) (car x) empty-wrap mod))
- (cons (cons er (source-wrap e w s mod))
- (cdr body)))))))))))))))))
-
- (define chi-local-syntax
- (lambda (rec? e r w s mod k)
- (syntax-case e ()
- ((_ ((id val) ...) e1 e2 ...)
- (let ((ids #'(id ...)))
- (if (not (valid-bound-ids? ids))
- (syntax-violation #f "duplicate bound keyword" e)
- (let ((labels (gen-labels ids)))
- (let ((new-w (make-binding-wrap ids labels w)))
- (k #'(e1 e2 ...)
- (extend-env
- labels
- (let ((w (if rec? new-w w))
- (trans-r (macros-only-env r)))
- (map (lambda (x)
- (make-binding 'macro
- (eval-local-transformer
- (chi x trans-r w mod)
- mod)))
- #'(val ...)))
- r)
- new-w
- s
- mod))))))
- (_ (syntax-violation #f "bad local syntax definition"
- (source-wrap e w s mod))))))
-
- (define eval-local-transformer
- (lambda (expanded mod)
- (let ((p (local-eval-hook expanded mod)))
- (if (procedure? p)
- p
- (syntax-violation #f "nonprocedure transformer" p)))))
-
- (define chi-void
- (lambda ()
- (build-void no-source)))
-
- (define ellipsis?
- (lambda (x)
- (and (nonsymbol-id? x)
- (free-id=? x #'(... ...)))))
-
- (define lambda-formals
- (lambda (orig-args)
- (define (req args rreq)
- (syntax-case args ()
- (()
- (check (reverse rreq) #f))
- ((a . b) (id? #'a)
- (req #'b (cons #'a rreq)))
- (r (id? #'r)
- (check (reverse rreq) #'r))
- (else
- (syntax-violation 'lambda "invalid argument list" orig-args args))))
- (define (check req rest)
- (cond
- ((distinct-bound-ids? (if rest (cons rest req) req))
- (values req #f rest #f))
- (else
- (syntax-violation 'lambda "duplicate identifier in argument list"
- orig-args))))
- (req orig-args '())))
-
- (define chi-simple-lambda
- (lambda (e r w s mod req rest meta body)
- (let* ((ids (if rest (append req (list rest)) req))
- (vars (map gen-var ids))
- (labels (gen-labels ids)))
- (build-simple-lambda
- s
- (map syntax->datum req) (and rest (syntax->datum rest)) vars
- meta
- (chi-body body (source-wrap e w s mod)
- (extend-var-env labels vars r)
- (make-binding-wrap ids labels w)
- mod)))))
-
- (define lambda*-formals
- (lambda (orig-args)
- (define (req args rreq)
- (syntax-case args ()
- (()
- (check (reverse rreq) '() #f '()))
- ((a . b) (id? #'a)
- (req #'b (cons #'a rreq)))
- ((a . b) (eq? (syntax->datum #'a) #:optional)
- (opt #'b (reverse rreq) '()))
- ((a . b) (eq? (syntax->datum #'a) #:key)
- (key #'b (reverse rreq) '() '()))
- ((a b) (eq? (syntax->datum #'a) #:rest)
- (rest #'b (reverse rreq) '() '()))
- (r (id? #'r)
- (rest #'r (reverse rreq) '() '()))
- (else
- (syntax-violation 'lambda* "invalid argument list" orig-args args))))
- (define (opt args req ropt)
- (syntax-case args ()
- (()
- (check req (reverse ropt) #f '()))
- ((a . b) (id? #'a)
- (opt #'b req (cons #'(a #f) ropt)))
- (((a init) . b) (id? #'a)
- (opt #'b req (cons #'(a init) ropt)))
- ((a . b) (eq? (syntax->datum #'a) #:key)
- (key #'b req (reverse ropt) '()))
- ((a b) (eq? (syntax->datum #'a) #:rest)
- (rest #'b req (reverse ropt) '()))
- (r (id? #'r)
- (rest #'r req (reverse ropt) '()))
- (else
- (syntax-violation 'lambda* "invalid optional argument list"
- orig-args args))))
- (define (key args req opt rkey)
- (syntax-case args ()
- (()
- (check req opt #f (cons #f (reverse rkey))))
- ((a . b) (id? #'a)
- (with-syntax ((k (symbol->keyword (syntax->datum #'a))))
- (key #'b req opt (cons #'(k a #f) rkey))))
- (((a init) . b) (id? #'a)
- (with-syntax ((k (symbol->keyword (syntax->datum #'a))))
- (key #'b req opt (cons #'(k a init) rkey))))
- (((a init k) . b) (and (id? #'a)
- (keyword? (syntax->datum #'k)))
- (key #'b req opt (cons #'(k a init) rkey)))
- ((aok) (eq? (syntax->datum #'aok) #:allow-other-keys)
- (check req opt #f (cons #t (reverse rkey))))
- ((aok a b) (and (eq? (syntax->datum #'aok) #:allow-other-keys)
- (eq? (syntax->datum #'a) #:rest))
- (rest #'b req opt (cons #t (reverse rkey))))
- ((aok . r) (and (eq? (syntax->datum #'aok) #:allow-other-keys)
- (id? #'r))
- (rest #'r req opt (cons #t (reverse rkey))))
- ((a b) (eq? (syntax->datum #'a) #:rest)
- (rest #'b req opt (cons #f (reverse rkey))))
- (r (id? #'r)
- (rest #'r req opt (cons #f (reverse rkey))))
- (else
- (syntax-violation 'lambda* "invalid keyword argument list"
- orig-args args))))
- (define (rest args req opt kw)
- (syntax-case args ()
- (r (id? #'r)
- (check req opt #'r kw))
- (else
- (syntax-violation 'lambda* "invalid rest argument"
- orig-args args))))
- (define (check req opt rest kw)
- (cond
- ((distinct-bound-ids?
- (append req (map car opt) (if rest (list rest) '())
- (if (pair? kw) (map cadr (cdr kw)) '())))
- (values req opt rest kw))
- (else
- (syntax-violation 'lambda* "duplicate identifier in argument list"
- orig-args))))
- (req orig-args '())))
-
- (define chi-lambda-case
- (lambda (e r w s mod get-formals clauses)
- (define (expand-req req opt rest kw body)
- (let ((vars (map gen-var req))
- (labels (gen-labels req)))
- (let ((r* (extend-var-env labels vars r))
- (w* (make-binding-wrap req labels w)))
- (expand-opt (map syntax->datum req)
- opt rest kw body (reverse vars) r* w* '() '()))))
- (define (expand-opt req opt rest kw body vars r* w* out inits)
- (cond
- ((pair? opt)
- (syntax-case (car opt) ()
- ((id i)
- (let* ((v (gen-var #'id))
- (l (gen-labels (list v)))
- (r** (extend-var-env l (list v) r*))
- (w** (make-binding-wrap (list #'id) l w*)))
- (expand-opt req (cdr opt) rest kw body (cons v vars)
- r** w** (cons (syntax->datum #'id) out)
- (cons (chi #'i r* w* mod) inits))))))
- (rest
- (let* ((v (gen-var rest))
- (l (gen-labels (list v)))
- (r* (extend-var-env l (list v) r*))
- (w* (make-binding-wrap (list rest) l w*)))
- (expand-kw req (if (pair? out) (reverse out) #f)
- (syntax->datum rest)
- (if (pair? kw) (cdr kw) kw)
- body (cons v vars) r* w*
- (if (pair? kw) (car kw) #f)
- '() inits)))
- (else
- (expand-kw req (if (pair? out) (reverse out) #f) #f
- (if (pair? kw) (cdr kw) kw)
- body vars r* w*
- (if (pair? kw) (car kw) #f)
- '() inits))))
- (define (expand-kw req opt rest kw body vars r* w* aok out inits)
- (cond
- ((pair? kw)
- (syntax-case (car kw) ()
- ((k id i)
- (let* ((v (gen-var #'id))
- (l (gen-labels (list v)))
- (r** (extend-var-env l (list v) r*))
- (w** (make-binding-wrap (list #'id) l w*)))
- (expand-kw req opt rest (cdr kw) body (cons v vars)
- r** w** aok
- (cons (list (syntax->datum #'k)
- (syntax->datum #'id)
- v)
- out)
- (cons (chi #'i r* w* mod) inits))))))
- (else
- (expand-body req opt rest
- (if (or aok (pair? out)) (cons aok (reverse out)) #f)
- body (reverse vars) r* w* (reverse inits) '()))))
- (define (expand-body req opt rest kw body vars r* w* inits meta)
- (syntax-case body ()
- ((docstring e1 e2 ...) (string? (syntax->datum #'docstring))
- (expand-body req opt rest kw #'(e1 e2 ...) vars r* w* inits
- (append meta
- `((documentation
- . ,(syntax->datum #'docstring))))))
- ((#((k . v) ...) e1 e2 ...)
- (expand-body req opt rest kw #'(e1 e2 ...) vars r* w* inits
- (append meta (syntax->datum #'((k . v) ...)))))
- ((e1 e2 ...)
- (values meta req opt rest kw inits vars
- (chi-body #'(e1 e2 ...) (source-wrap e w s mod)
- r* w* mod)))))
-
- (syntax-case clauses ()
- (() (values '() #f))
- (((args e1 e2 ...) (args* e1* e2* ...) ...)
- (call-with-values (lambda () (get-formals #'args))
- (lambda (req opt rest kw)
- (call-with-values (lambda ()
- (expand-req req opt rest kw #'(e1 e2 ...)))
- (lambda (meta req opt rest kw inits vars body)
- (call-with-values
- (lambda ()
- (chi-lambda-case e r w s mod get-formals
- #'((args* e1* e2* ...) ...)))
- (lambda (meta* else*)
- (values
- (append meta meta*)
- (build-lambda-case s req opt rest kw inits vars
- body else*))))))))))))
-
-;;; data
-
-;;; strips syntax-objects down to top-wrap
-;;;
-;;; since only the head of a list is annotated by the reader, not each pair
-;;; in the spine, we also check for pairs whose cars are annotated in case
-;;; we've been passed the cdr of an annotated list
-
- (define strip
- (lambda (x w)
- (if (top-marked? w)
- x
- (let f ((x x))
- (cond
- ((syntax-object? x)
- (strip (syntax-object-expression x) (syntax-object-wrap x)))
- ((pair? x)
- (let ((a (f (car x))) (d (f (cdr x))))
- (if (and (eq? a (car x)) (eq? d (cdr x)))
- x
- (cons a d))))
- ((vector? x)
- (let ((old (vector->list x)))
- (let ((new (map f old)))
- (if (and-map* eq? old new) x (list->vector new)))))
- (else x))))))
-
-;;; lexical variables
-
- (define gen-var
- (lambda (id)
- (let ((id (if (syntax-object? id) (syntax-object-expression id) id)))
- (build-lexical-var no-source id))))
-
- ;; appears to return a reversed list
- (define lambda-var-list
- (lambda (vars)
- (let lvl ((vars vars) (ls '()) (w empty-wrap))
- (cond
- ((pair? vars) (lvl (cdr vars) (cons (wrap (car vars) w #f) ls) w))
- ((id? vars) (cons (wrap vars w #f) ls))
- ((null? vars) ls)
- ((syntax-object? vars)
- (lvl (syntax-object-expression vars)
- ls
- (join-wraps w (syntax-object-wrap vars))))
- ;; include anything else to be caught by subsequent error
- ;; checking
- (else (cons vars ls))))))
-
-;;; core transformers
-
- (global-extend 'local-syntax 'letrec-syntax #t)
- (global-extend 'local-syntax 'let-syntax #f)
-
- (global-extend 'core 'fluid-let-syntax
- (lambda (e r w s mod)
- (syntax-case e ()
- ((_ ((var val) ...) e1 e2 ...)
- (valid-bound-ids? #'(var ...))
- (let ((names (map (lambda (x) (id-var-name x w)) #'(var ...))))
- (for-each
- (lambda (id n)
- (case (binding-type (lookup n r mod))
- ((displaced-lexical)
- (syntax-violation 'fluid-let-syntax
- "identifier out of context"
- e
- (source-wrap id w s mod)))))
- #'(var ...)
- names)
- (chi-body
- #'(e1 e2 ...)
- (source-wrap e w s mod)
- (extend-env
- names
- (let ((trans-r (macros-only-env r)))
- (map (lambda (x)
- (make-binding 'macro
- (eval-local-transformer (chi x trans-r w mod)
- mod)))
- #'(val ...)))
- r)
- w
- mod)))
- (_ (syntax-violation 'fluid-let-syntax "bad syntax"
- (source-wrap e w s mod))))))
-
- (global-extend 'core 'quote
- (lambda (e r w s mod)
- (syntax-case e ()
- ((_ e) (build-data s (strip #'e w)))
- (_ (syntax-violation 'quote "bad syntax"
- (source-wrap e w s mod))))))
-
- (global-extend 'core 'syntax
- (let ()
- (define gen-syntax
- (lambda (src e r maps ellipsis? mod)
- (if (id? e)
- (let ((label (id-var-name e empty-wrap)))
- ;; Mod does not matter, we are looking to see if
- ;; the id is lexical syntax.
- (let ((b (lookup label r mod)))
- (if (eq? (binding-type b) 'syntax)
- (call-with-values
- (lambda ()
- (let ((var.lev (binding-value b)))
- (gen-ref src (car var.lev) (cdr var.lev) maps)))
- (lambda (var maps) (values `(ref ,var) maps)))
- (if (ellipsis? e)
- (syntax-violation 'syntax "misplaced ellipsis" src)
- (values `(quote ,e) maps)))))
- (syntax-case e ()
- ((dots e)
- (ellipsis? #'dots)
- (gen-syntax src #'e r maps (lambda (x) #f) mod))
- ((x dots . y)
- ;; this could be about a dozen lines of code, except that we
- ;; choose to handle #'(x ... ...) forms
- (ellipsis? #'dots)
- (let f ((y #'y)
- (k (lambda (maps)
- (call-with-values
- (lambda ()
- (gen-syntax src #'x r
- (cons '() maps) ellipsis? mod))
- (lambda (x maps)
- (if (null? (car maps))
- (syntax-violation 'syntax "extra ellipsis"
- src)
- (values (gen-map x (car maps))
- (cdr maps))))))))
- (syntax-case y ()
- ((dots . y)
- (ellipsis? #'dots)
- (f #'y
- (lambda (maps)
- (call-with-values
- (lambda () (k (cons '() maps)))
- (lambda (x maps)
- (if (null? (car maps))
- (syntax-violation 'syntax "extra ellipsis" src)
- (values (gen-mappend x (car maps))
- (cdr maps))))))))
- (_ (call-with-values
- (lambda () (gen-syntax src y r maps ellipsis? mod))
- (lambda (y maps)
- (call-with-values
- (lambda () (k maps))
- (lambda (x maps)
- (values (gen-append x y) maps)))))))))
- ((x . y)
- (call-with-values
- (lambda () (gen-syntax src #'x r maps ellipsis? mod))
- (lambda (x maps)
- (call-with-values
- (lambda () (gen-syntax src #'y r maps ellipsis? mod))
- (lambda (y maps) (values (gen-cons x y) maps))))))
- (#(e1 e2 ...)
- (call-with-values
- (lambda ()
- (gen-syntax src #'(e1 e2 ...) r maps ellipsis? mod))
- (lambda (e maps) (values (gen-vector e) maps))))
- (_ (values `(quote ,e) maps))))))
-
- (define gen-ref
- (lambda (src var level maps)
- (if (fx= level 0)
- (values var maps)
- (if (null? maps)
- (syntax-violation 'syntax "missing ellipsis" src)
- (call-with-values
- (lambda () (gen-ref src var (fx- level 1) (cdr maps)))
- (lambda (outer-var outer-maps)
- (let ((b (assq outer-var (car maps))))
- (if b
- (values (cdr b) maps)
- (let ((inner-var (gen-var 'tmp)))
- (values inner-var
- (cons (cons (cons outer-var inner-var)
- (car maps))
- outer-maps)))))))))))
-
- (define gen-mappend
- (lambda (e map-env)
- `(apply (primitive append) ,(gen-map e map-env))))
-
- (define gen-map
- (lambda (e map-env)
- (let ((formals (map cdr map-env))
- (actuals (map (lambda (x) `(ref ,(car x))) map-env)))
- (cond
- ((eq? (car e) 'ref)
- ;; identity map equivalence:
- ;; (map (lambda (x) x) y) == y
- (car actuals))
- ((and-map
- (lambda (x) (and (eq? (car x) 'ref) (memq (cadr x) formals)))
- (cdr e))
- ;; eta map equivalence:
- ;; (map (lambda (x ...) (f x ...)) y ...) == (map f y ...)
- `(map (primitive ,(car e))
- ,@(map (let ((r (map cons formals actuals)))
- (lambda (x) (cdr (assq (cadr x) r))))
- (cdr e))))
- (else `(map (lambda ,formals ,e) ,@actuals))))))
-
- (define gen-cons
- (lambda (x y)
- (case (car y)
- ((quote)
- (if (eq? (car x) 'quote)
- `(quote (,(cadr x) . ,(cadr y)))
- (if (eq? (cadr y) '())
- `(list ,x)
- `(cons ,x ,y))))
- ((list) `(list ,x ,@(cdr y)))
- (else `(cons ,x ,y)))))
-
- (define gen-append
- (lambda (x y)
- (if (equal? y '(quote ()))
- x
- `(append ,x ,y))))
-
- (define gen-vector
- (lambda (x)
- (cond
- ((eq? (car x) 'list) `(vector ,@(cdr x)))
- ((eq? (car x) 'quote) `(quote #(,@(cadr x))))
- (else `(list->vector ,x)))))
-
-
- (define regen
- (lambda (x)
- (case (car x)
- ((ref) (build-lexical-reference 'value no-source (cadr x) (cadr x)))
- ((primitive) (build-primref no-source (cadr x)))
- ((quote) (build-data no-source (cadr x)))
- ((lambda)
- (if (list? (cadr x))
- (build-simple-lambda no-source (cadr x) #f (cadr x) '() (regen (caddr x)))
- (error "how did we get here" x)))
- (else (build-application no-source
- (build-primref no-source (car x))
- (map regen (cdr x)))))))
-
- (lambda (e r w s mod)
- (let ((e (source-wrap e w s mod)))
- (syntax-case e ()
- ((_ x)
- (call-with-values
- (lambda () (gen-syntax e #'x r '() ellipsis? mod))
- (lambda (e maps) (regen e))))
- (_ (syntax-violation 'syntax "bad `syntax' form" e)))))))
-
- (global-extend 'core 'lambda
- (lambda (e r w s mod)
- (syntax-case e ()
- ((_ args e1 e2 ...)
- (call-with-values (lambda () (lambda-formals #'args))
- (lambda (req opt rest kw)
- (let lp ((body #'(e1 e2 ...)) (meta '()))
- (syntax-case body ()
- ((docstring e1 e2 ...) (string? (syntax->datum #'docstring))
- (lp #'(e1 e2 ...)
- (append meta
- `((documentation
- . ,(syntax->datum #'docstring))))))
- ((#((k . v) ...) e1 e2 ...)
- (lp #'(e1 e2 ...)
- (append meta (syntax->datum #'((k . v) ...)))))
- (_ (chi-simple-lambda e r w s mod req rest meta body)))))))
- (_ (syntax-violation 'lambda "bad lambda" e)))))
-
- (global-extend 'core 'lambda*
- (lambda (e r w s mod)
- (syntax-case e ()
- ((_ args e1 e2 ...)
- (call-with-values
- (lambda ()
- (chi-lambda-case e r w s mod
- lambda*-formals #'((args e1 e2 ...))))
- (lambda (meta lcase)
- (build-case-lambda s meta lcase))))
- (_ (syntax-violation 'lambda "bad lambda*" e)))))
-
- (global-extend 'core 'case-lambda
- (lambda (e r w s mod)
- (syntax-case e ()
- ((_ (args e1 e2 ...) (args* e1* e2* ...) ...)
- (call-with-values
- (lambda ()
- (chi-lambda-case e r w s mod
- lambda-formals
- #'((args e1 e2 ...) (args* e1* e2* ...) ...)))
- (lambda (meta lcase)
- (build-case-lambda s meta lcase))))
- (_ (syntax-violation 'case-lambda "bad case-lambda" e)))))
-
- (global-extend 'core 'case-lambda*
- (lambda (e r w s mod)
- (syntax-case e ()
- ((_ (args e1 e2 ...) (args* e1* e2* ...) ...)
- (call-with-values
- (lambda ()
- (chi-lambda-case e r w s mod
- lambda*-formals
- #'((args e1 e2 ...) (args* e1* e2* ...) ...)))
- (lambda (meta lcase)
- (build-case-lambda s meta lcase))))
- (_ (syntax-violation 'case-lambda "bad case-lambda*" e)))))
-
- (global-extend 'core 'let
- (let ()
- (define (chi-let e r w s mod constructor ids vals exps)
- (if (not (valid-bound-ids? ids))
- (syntax-violation 'let "duplicate bound variable" e)
- (let ((labels (gen-labels ids))
- (new-vars (map gen-var ids)))
- (let ((nw (make-binding-wrap ids labels w))
- (nr (extend-var-env labels new-vars r)))
- (constructor s
- (map syntax->datum ids)
- new-vars
- (map (lambda (x) (chi x r w mod)) vals)
- (chi-body exps (source-wrap e nw s mod)
- nr nw mod))))))
- (lambda (e r w s mod)
- (syntax-case e ()
- ((_ ((id val) ...) e1 e2 ...)
- (and-map id? #'(id ...))
- (chi-let e r w s mod
- build-let
- #'(id ...)
- #'(val ...)
- #'(e1 e2 ...)))
- ((_ f ((id val) ...) e1 e2 ...)
- (and (id? #'f) (and-map id? #'(id ...)))
- (chi-let e r w s mod
- build-named-let
- #'(f id ...)
- #'(val ...)
- #'(e1 e2 ...)))
- (_ (syntax-violation 'let "bad let" (source-wrap e w s mod)))))))
-
-
- (global-extend 'core 'letrec
- (lambda (e r w s mod)
- (syntax-case e ()
- ((_ ((id val) ...) e1 e2 ...)
- (and-map id? #'(id ...))
- (let ((ids #'(id ...)))
- (if (not (valid-bound-ids? ids))
- (syntax-violation 'letrec "duplicate bound variable" e)
- (let ((labels (gen-labels ids))
- (new-vars (map gen-var ids)))
- (let ((w (make-binding-wrap ids labels w))
- (r (extend-var-env labels new-vars r)))
- (build-letrec s #f
- (map syntax->datum ids)
- new-vars
- (map (lambda (x) (chi x r w mod)) #'(val ...))
- (chi-body #'(e1 e2 ...)
- (source-wrap e w s mod) r w mod)))))))
- (_ (syntax-violation 'letrec "bad letrec" (source-wrap e w s mod))))))
-
-
- (global-extend 'core 'letrec*
- (lambda (e r w s mod)
- (syntax-case e ()
- ((_ ((id val) ...) e1 e2 ...)
- (and-map id? #'(id ...))
- (let ((ids #'(id ...)))
- (if (not (valid-bound-ids? ids))
- (syntax-violation 'letrec* "duplicate bound variable" e)
- (let ((labels (gen-labels ids))
- (new-vars (map gen-var ids)))
- (let ((w (make-binding-wrap ids labels w))
- (r (extend-var-env labels new-vars r)))
- (build-letrec s #t
- (map syntax->datum ids)
- new-vars
- (map (lambda (x) (chi x r w mod)) #'(val ...))
- (chi-body #'(e1 e2 ...)
- (source-wrap e w s mod) r w mod)))))))
- (_ (syntax-violation 'letrec* "bad letrec*" (source-wrap e w s mod))))))
-
-
- (global-extend 'core 'set!
- (lambda (e r w s mod)
- (syntax-case e ()
- ((_ id val)
- (id? #'id)
- (let ((n (id-var-name #'id w))
- ;; Lookup id in its module
- (id-mod (if (syntax-object? #'id)
- (syntax-object-module #'id)
- mod)))
- (let ((b (lookup n r id-mod)))
- (case (binding-type b)
- ((lexical)
- (build-lexical-assignment s
- (syntax->datum #'id)
- (binding-value b)
- (chi #'val r w mod)))
- ((global)
- (build-global-assignment s n (chi #'val r w mod) id-mod))
- ((macro)
- (let ((p (binding-value b)))
- (if (procedure-property p 'variable-transformer)
- ;; As syntax-type does, call chi-macro with
- ;; the mod of the expression. Hmm.
- (chi (chi-macro p e r w s #f mod) r empty-wrap mod)
- (syntax-violation 'set! "not a variable transformer"
- (wrap e w mod)
- (wrap #'id w id-mod)))))
- ((displaced-lexical)
- (syntax-violation 'set! "identifier out of context"
- (wrap #'id w mod)))
- (else (syntax-violation 'set! "bad set!"
- (source-wrap e w s mod)))))))
- ((_ (head tail ...) val)
- (call-with-values
- (lambda () (syntax-type #'head r empty-wrap no-source #f mod #t))
- (lambda (type value ee ww ss modmod)
- (case type
- ((module-ref)
- (let ((val (chi #'val r w mod)))
- (call-with-values (lambda () (value #'(head tail ...) r w))
- (lambda (e r w s* mod)
- (syntax-case e ()
- (e (id? #'e)
- (build-global-assignment s (syntax->datum #'e)
- val mod)))))))
- (else
- (build-application s
- (chi #'(setter head) r w mod)
- (map (lambda (e) (chi e r w mod))
- #'(tail ... val))))))))
- (_ (syntax-violation 'set! "bad set!" (source-wrap e w s mod))))))
-
- (global-extend 'module-ref '@
- (lambda (e r w)
- (syntax-case e ()
- ((_ (mod ...) id)
- (and (and-map id? #'(mod ...)) (id? #'id))
- (values (syntax->datum #'id) r w #f
- (syntax->datum
- #'(public mod ...)))))))
-
- (global-extend 'module-ref '@@
- (lambda (e r w)
- (define remodulate
- (lambda (x mod)
- (cond ((pair? x)
- (cons (remodulate (car x) mod)
- (remodulate (cdr x) mod)))
- ((syntax-object? x)
- (make-syntax-object
- (remodulate (syntax-object-expression x) mod)
- (syntax-object-wrap x)
- ;; hither the remodulation
- mod))
- ((vector? x)
- (let* ((n (vector-length x)) (v (make-vector n)))
- (do ((i 0 (fx+ i 1)))
- ((fx= i n) v)
- (vector-set! v i (remodulate (vector-ref x i) mod)))))
- (else x))))
- (syntax-case e ()
- ((_ (mod ...) exp)
- (and-map id? #'(mod ...))
- (let ((mod (syntax->datum #'(private mod ...))))
- (values (remodulate #'exp mod)
- r w (source-annotation #'exp)
- mod))))))
-
- (global-extend 'core 'if
- (lambda (e r w s mod)
- (syntax-case e ()
- ((_ test then)
- (build-conditional
- s
- (chi #'test r w mod)
- (chi #'then r w mod)
- (build-void no-source)))
- ((_ test then else)
- (build-conditional
- s
- (chi #'test r w mod)
- (chi #'then r w mod)
- (chi #'else r w mod))))))
-
- (global-extend 'core 'with-fluids
- (lambda (e r w s mod)
- (syntax-case e ()
- ((_ ((fluid val) ...) b b* ...)
- (build-dynlet
- s
- (map (lambda (x) (chi x r w mod)) #'(fluid ...))
- (map (lambda (x) (chi x r w mod)) #'(val ...))
- (chi-body #'(b b* ...)
- (source-wrap e w s mod) r w mod))))))
-
- (global-extend 'begin 'begin '())
-
- (global-extend 'define 'define '())
-
- (global-extend 'define-syntax 'define-syntax '())
-
- (global-extend 'eval-when 'eval-when '())
-
- (global-extend 'core 'syntax-case
- (let ()
- (define convert-pattern
- ;; accepts pattern & keys
- ;; returns $sc-dispatch pattern & ids
- (lambda (pattern keys)
- (define cvt*
- (lambda (p* n ids)
- (if (null? p*)
- (values '() ids)
- (call-with-values
- (lambda () (cvt* (cdr p*) n ids))
- (lambda (y ids)
- (call-with-values
- (lambda () (cvt (car p*) n ids))
- (lambda (x ids)
- (values (cons x y) ids))))))))
- (define cvt
- (lambda (p n ids)
- (if (id? p)
- (cond
- ((bound-id-member? p keys)
- (values (vector 'free-id p) ids))
- ((free-id=? p #'_)
- (values '_ ids))
- (else
- (values 'any (cons (cons p n) ids))))
- (syntax-case p ()
- ((x dots)
- (ellipsis? (syntax dots))
- (call-with-values
- (lambda () (cvt (syntax x) (fx+ n 1) ids))
- (lambda (p ids)
- (values (if (eq? p 'any) 'each-any (vector 'each p))
- ids))))
- ((x dots ys ...)
- (ellipsis? (syntax dots))
- (call-with-values
- (lambda () (cvt* (syntax (ys ...)) n ids))
- (lambda (ys ids)
- (call-with-values
- (lambda () (cvt (syntax x) (+ n 1) ids))
- (lambda (x ids)
- (values `#(each+ ,x ,(reverse ys) ()) ids))))))
- ((x . y)
- (call-with-values
- (lambda () (cvt (syntax y) n ids))
- (lambda (y ids)
- (call-with-values
- (lambda () (cvt (syntax x) n ids))
- (lambda (x ids)
- (values (cons x y) ids))))))
- (() (values '() ids))
- (#(x ...)
- (call-with-values
- (lambda () (cvt (syntax (x ...)) n ids))
- (lambda (p ids) (values (vector 'vector p) ids))))
- (x (values (vector 'atom (strip p empty-wrap)) ids))))))
- (cvt pattern 0 '())))
-
- (define build-dispatch-call
- (lambda (pvars exp y r mod)
- (let ((ids (map car pvars)) (levels (map cdr pvars)))
- (let ((labels (gen-labels ids)) (new-vars (map gen-var ids)))
- (build-application no-source
- (build-primref no-source 'apply)
- (list (build-simple-lambda no-source (map syntax->datum ids) #f new-vars '()
- (chi exp
- (extend-env
- labels
- (map (lambda (var level)
- (make-binding 'syntax `(,var . ,level)))
- new-vars
- (map cdr pvars))
- r)
- (make-binding-wrap ids labels empty-wrap)
- mod))
- y))))))
-
- (define gen-clause
- (lambda (x keys clauses r pat fender exp mod)
- (call-with-values
- (lambda () (convert-pattern pat keys))
- (lambda (p pvars)
- (cond
- ((not (distinct-bound-ids? (map car pvars)))
- (syntax-violation 'syntax-case "duplicate pattern variable" pat))
- ((not (and-map (lambda (x) (not (ellipsis? (car x)))) pvars))
- (syntax-violation 'syntax-case "misplaced ellipsis" pat))
- (else
- (let ((y (gen-var 'tmp)))
- ;; fat finger binding and references to temp variable y
- (build-application no-source
- (build-simple-lambda no-source (list 'tmp) #f (list y) '()
- (let ((y (build-lexical-reference 'value no-source
- 'tmp y)))
- (build-conditional no-source
- (syntax-case fender ()
- (#t y)
- (_ (build-conditional no-source
- y
- (build-dispatch-call pvars fender y r mod)
- (build-data no-source #f))))
- (build-dispatch-call pvars exp y r mod)
- (gen-syntax-case x keys clauses r mod))))
- (list (if (eq? p 'any)
- (build-application no-source
- (build-primref no-source 'list)
- (list x))
- (build-application no-source
- (build-primref no-source '$sc-dispatch)
- (list x (build-data no-source p)))))))))))))
-
- (define gen-syntax-case
- (lambda (x keys clauses r mod)
- (if (null? clauses)
- (build-application no-source
- (build-primref no-source 'syntax-violation)
- (list (build-data no-source #f)
- (build-data no-source
- "source expression failed to match any pattern")
- x))
- (syntax-case (car clauses) ()
- ((pat exp)
- (if (and (id? #'pat)
- (and-map (lambda (x) (not (free-id=? #'pat x)))
- (cons #'(... ...) keys)))
- (if (free-id=? #'pad #'_)
- (chi #'exp r empty-wrap mod)
- (let ((labels (list (gen-label)))
- (var (gen-var #'pat)))
- (build-application no-source
- (build-simple-lambda
- no-source (list (syntax->datum #'pat)) #f (list var)
- '()
- (chi #'exp
- (extend-env labels
- (list (make-binding 'syntax `(,var . 0)))
- r)
- (make-binding-wrap #'(pat)
- labels empty-wrap)
- mod))
- (list x))))
- (gen-clause x keys (cdr clauses) r
- #'pat #t #'exp mod)))
- ((pat fender exp)
- (gen-clause x keys (cdr clauses) r
- #'pat #'fender #'exp mod))
- (_ (syntax-violation 'syntax-case "invalid clause"
- (car clauses)))))))
-
- (lambda (e r w s mod)
- (let ((e (source-wrap e w s mod)))
- (syntax-case e ()
- ((_ val (key ...) m ...)
- (if (and-map (lambda (x) (and (id? x) (not (ellipsis? x))))
- #'(key ...))
- (let ((x (gen-var 'tmp)))
- ;; fat finger binding and references to temp variable x
- (build-application s
- (build-simple-lambda no-source (list 'tmp) #f (list x) '()
- (gen-syntax-case (build-lexical-reference 'value no-source
- 'tmp x)
- #'(key ...) #'(m ...)
- r
- mod))
- (list (chi #'val r empty-wrap mod))))
- (syntax-violation 'syntax-case "invalid literals list" e))))))))
-
-;;; The portable macroexpand seeds chi-top's mode m with 'e (for
-;;; evaluating) and esew (which stands for "eval syntax expanders
-;;; when") with '(eval). In Chez Scheme, m is set to 'c instead of e
-;;; if we are compiling a file, and esew is set to
-;;; (eval-syntactic-expanders-when), which defaults to the list
-;;; '(compile load eval). This means that, by default, top-level
-;;; syntactic definitions are evaluated immediately after they are
-;;; expanded, and the expanded definitions are also residualized into
-;;; the object file if we are compiling a file.
- (set! macroexpand
- (lambda* (x #:optional (m 'e) (esew '(eval)))
- (chi-top x null-env top-wrap m esew
- (cons 'hygiene (module-name (current-module))))))
-
- (set! identifier?
- (lambda (x)
- (nonsymbol-id? x)))
-
- (set! datum->syntax
- (lambda (id datum)
- (make-syntax-object datum (syntax-object-wrap id)
- (syntax-object-module id))))
-
- (set! syntax->datum
- ;; accepts any object, since syntax objects may consist partially
- ;; or entirely of unwrapped, nonsymbolic data
- (lambda (x)
- (strip x empty-wrap)))
-
- (set! syntax-source
- (lambda (x) (source-annotation x)))
-
- (set! generate-temporaries
- (lambda (ls)
- (arg-check list? ls 'generate-temporaries)
- (map (lambda (x) (wrap (gensym-hook) top-wrap #f)) ls)))
-
- (set! free-identifier=?
- (lambda (x y)
- (arg-check nonsymbol-id? x 'free-identifier=?)
- (arg-check nonsymbol-id? y 'free-identifier=?)
- (free-id=? x y)))
-
- (set! bound-identifier=?
- (lambda (x y)
- (arg-check nonsymbol-id? x 'bound-identifier=?)
- (arg-check nonsymbol-id? y 'bound-identifier=?)
- (bound-id=? x y)))
-
- (set! syntax-violation
- (lambda (who message form . subform)
- (arg-check (lambda (x) (or (not x) (string? x) (symbol? x)))
- who 'syntax-violation)
- (arg-check string? message 'syntax-violation)
- (scm-error 'syntax-error 'macroexpand
- (string-append
- (if who "~a: " "")
- "~a "
- (if (null? subform) "in ~a" "in subform `~s' of `~s'"))
- (let ((tail (cons message
- (map (lambda (x) (strip x empty-wrap))
- (append subform (list form))))))
- (if who (cons who tail) tail))
- #f)))
-
-;;; $sc-dispatch expects an expression and a pattern. If the expression
-;;; matches the pattern a list of the matching expressions for each
-;;; "any" is returned. Otherwise, #f is returned. (This use of #f will
-;;; not work on r4rs implementations that violate the ieee requirement
-;;; that #f and () be distinct.)
-
-;;; The expression is matched with the pattern as follows:
-
-;;; pattern: matches:
-;;; () empty list
-;;; any anything
-;;; (<pattern>1 . <pattern>2) (<pattern>1 . <pattern>2)
-;;; each-any (any*)
-;;; #(free-id <key>) <key> with free-identifier=?
-;;; #(each <pattern>) (<pattern>*)
-;;; #(each+ p1 (p2_1 ... p2_n) p3) (p1* (p2_n ... p2_1) . p3)
-;;; #(vector <pattern>) (list->vector <pattern>)
-;;; #(atom <object>) <object> with "equal?"
-
-;;; Vector cops out to pair under assumption that vectors are rare. If
-;;; not, should convert to:
-;;; #(vector <pattern>*) #(<pattern>*)
-
- (let ()
-
- (define match-each
- (lambda (e p w mod)
- (cond
- ((pair? e)
- (let ((first (match (car e) p w '() mod)))
- (and first
- (let ((rest (match-each (cdr e) p w mod)))
- (and rest (cons first rest))))))
- ((null? e) '())
- ((syntax-object? e)
- (match-each (syntax-object-expression e)
- p
- (join-wraps w (syntax-object-wrap e))
- (syntax-object-module e)))
- (else #f))))
-
- (define match-each+
- (lambda (e x-pat y-pat z-pat w r mod)
- (let f ((e e) (w w))
- (cond
- ((pair? e)
- (call-with-values (lambda () (f (cdr e) w))
- (lambda (xr* y-pat r)
- (if r
- (if (null? y-pat)
- (let ((xr (match (car e) x-pat w '() mod)))
- (if xr
- (values (cons xr xr*) y-pat r)
- (values #f #f #f)))
- (values
- '()
- (cdr y-pat)
- (match (car e) (car y-pat) w r mod)))
- (values #f #f #f)))))
- ((syntax-object? e)
- (f (syntax-object-expression e) (join-wraps w e)))
- (else
- (values '() y-pat (match e z-pat w r mod)))))))
-
- (define match-each-any
- (lambda (e w mod)
- (cond
- ((pair? e)
- (let ((l (match-each-any (cdr e) w mod)))
- (and l (cons (wrap (car e) w mod) l))))
- ((null? e) '())
- ((syntax-object? e)
- (match-each-any (syntax-object-expression e)
- (join-wraps w (syntax-object-wrap e))
- mod))
- (else #f))))
-
- (define match-empty
- (lambda (p r)
- (cond
- ((null? p) r)
- ((eq? p '_) r)
- ((eq? p 'any) (cons '() r))
- ((pair? p) (match-empty (car p) (match-empty (cdr p) r)))
- ((eq? p 'each-any) (cons '() r))
- (else
- (case (vector-ref p 0)
- ((each) (match-empty (vector-ref p 1) r))
- ((each+) (match-empty (vector-ref p 1)
- (match-empty
- (reverse (vector-ref p 2))
- (match-empty (vector-ref p 3) r))))
- ((free-id atom) r)
- ((vector) (match-empty (vector-ref p 1) r)))))))
-
- (define combine
- (lambda (r* r)
- (if (null? (car r*))
- r
- (cons (map car r*) (combine (map cdr r*) r)))))
-
- (define match*
- (lambda (e p w r mod)
- (cond
- ((null? p) (and (null? e) r))
- ((pair? p)
- (and (pair? e) (match (car e) (car p) w
- (match (cdr e) (cdr p) w r mod)
- mod)))
- ((eq? p 'each-any)
- (let ((l (match-each-any e w mod))) (and l (cons l r))))
- (else
- (case (vector-ref p 0)
- ((each)
- (if (null? e)
- (match-empty (vector-ref p 1) r)
- (let ((l (match-each e (vector-ref p 1) w mod)))
- (and l
- (let collect ((l l))
- (if (null? (car l))
- r
- (cons (map car l) (collect (map cdr l)))))))))
- ((each+)
- (call-with-values
- (lambda ()
- (match-each+ e (vector-ref p 1) (vector-ref p 2) (vector-ref p 3) w r mod))
- (lambda (xr* y-pat r)
- (and r
- (null? y-pat)
- (if (null? xr*)
- (match-empty (vector-ref p 1) r)
- (combine xr* r))))))
- ((free-id) (and (id? e) (free-id=? (wrap e w mod) (vector-ref p 1)) r))
- ((atom) (and (equal? (vector-ref p 1) (strip e w)) r))
- ((vector)
- (and (vector? e)
- (match (vector->list e) (vector-ref p 1) w r mod))))))))
-
- (define match
- (lambda (e p w r mod)
- (cond
- ((not r) #f)
- ((eq? p '_) r)
- ((eq? p 'any) (cons (wrap e w mod) r))
- ((syntax-object? e)
- (match*
- (syntax-object-expression e)
- p
- (join-wraps w (syntax-object-wrap e))
- r
- (syntax-object-module e)))
- (else (match* e p w r mod)))))
-
- (set! $sc-dispatch
- (lambda (e p)
- (cond
- ((eq? p 'any) (list e))
- ((eq? p '_) '())
- ((syntax-object? e)
- (match* (syntax-object-expression e)
- p (syntax-object-wrap e) '() (syntax-object-module e)))
- (else (match* e p empty-wrap '() #f)))))
-
- ))
-)
-
-(define-syntax with-syntax
- (lambda (x)
- (syntax-case x ()
- ((_ () e1 e2 ...)
- #'(begin e1 e2 ...))
- ((_ ((out in)) e1 e2 ...)
- #'(syntax-case in () (out (begin e1 e2 ...))))
- ((_ ((out in) ...) e1 e2 ...)
- #'(syntax-case (list in ...) ()
- ((out ...) (begin e1 e2 ...)))))))
-
-(define-syntax syntax-rules
- (lambda (x)
- (syntax-case x ()
- ((_ (k ...) ((keyword . pattern) template) ...)
- #'(lambda (x)
- ;; embed patterns as procedure metadata
- #((macro-type . syntax-rules)
- (patterns pattern ...))
- (syntax-case x (k ...)
- ((dummy . pattern) #'template)
- ...))))))
-
-(define-syntax let*
- (lambda (x)
- (syntax-case x ()
- ((let* ((x v) ...) e1 e2 ...)
- (and-map identifier? #'(x ...))
- (let f ((bindings #'((x v) ...)))
- (if (null? bindings)
- #'(let () e1 e2 ...)
- (with-syntax ((body (f (cdr bindings)))
- (binding (car bindings)))
- #'(let (binding) body))))))))
-
-(define-syntax do
- (lambda (orig-x)
- (syntax-case orig-x ()
- ((_ ((var init . step) ...) (e0 e1 ...) c ...)
- (with-syntax (((step ...)
- (map (lambda (v s)
- (syntax-case s ()
- (() v)
- ((e) #'e)
- (_ (syntax-violation
- 'do "bad step expression"
- orig-x s))))
- #'(var ...)
- #'(step ...))))
- (syntax-case #'(e1 ...) ()
- (() #'(let doloop ((var init) ...)
- (if (not e0)
- (begin c ... (doloop step ...)))))
- ((e1 e2 ...)
- #'(let doloop ((var init) ...)
- (if e0
- (begin e1 e2 ...)
- (begin c ... (doloop step ...)))))))))))
-
-(define-syntax quasiquote
- (letrec
- ((quasicons
- (lambda (x y)
- (with-syntax ((x x) (y y))
- (syntax-case #'y (quote list)
- ((quote dy)
- (syntax-case #'x (quote)
- ((quote dx) #'(quote (dx . dy)))
- (_ (if (null? #'dy)
- #'(list x)
- #'(cons x y)))))
- ((list . stuff) #'(list x . stuff))
- (else #'(cons x y))))))
- (quasiappend
- (lambda (x y)
- (with-syntax ((x x) (y y))
- (syntax-case #'y (quote)
- ((quote ()) #'x)
- (_ #'(append x y))))))
- (quasivector
- (lambda (x)
- (with-syntax ((x x))
- (syntax-case #'x (quote list)
- ((quote (x ...)) #'(quote #(x ...)))
- ((list x ...) #'(vector x ...))
- (_ #'(list->vector x))))))
- (quasi
- (lambda (p lev)
- (syntax-case p (unquote unquote-splicing quasiquote)
- ((unquote p)
- (if (= lev 0)
- #'p
- (quasicons #'(quote unquote)
- (quasi #'(p) (- lev 1)))))
- ((unquote . args)
- (= lev 0)
- (syntax-violation 'unquote
- "unquote takes exactly one argument"
- p #'(unquote . args)))
- (((unquote-splicing p) . q)
- (if (= lev 0)
- (quasiappend #'p (quasi #'q lev))
- (quasicons (quasicons #'(quote unquote-splicing)
- (quasi #'(p) (- lev 1)))
- (quasi #'q lev))))
- (((unquote-splicing . args) . q)
- (= lev 0)
- (syntax-violation 'unquote-splicing
- "unquote-splicing takes exactly one argument"
- p #'(unquote-splicing . args)))
- ((quasiquote p)
- (quasicons #'(quote quasiquote)
- (quasi #'(p) (+ lev 1))))
- ((p . q)
- (quasicons (quasi #'p lev) (quasi #'q lev)))
- (#(x ...) (quasivector (quasi #'(x ...) lev)))
- (p #'(quote p))))))
- (lambda (x)
- (syntax-case x ()
- ((_ e) (quasi #'e 0))))))
-
-(define-syntax include
- (lambda (x)
- (define read-file
- (lambda (fn k)
- (let ((p (open-input-file fn)))
- (let f ((x (read p))
- (result '()))
- (if (eof-object? x)
- (begin
- (close-input-port p)
- (reverse result))
- (f (read p)
- (cons (datum->syntax k x) result)))))))
- (syntax-case x ()
- ((k filename)
- (let ((fn (syntax->datum #'filename)))
- (with-syntax (((exp ...) (read-file fn #'filename)))
- #'(begin exp ...)))))))
-
-(define-syntax include-from-path
- (lambda (x)
- (syntax-case x ()
- ((k filename)
- (let ((fn (syntax->datum #'filename)))
- (with-syntax ((fn (datum->syntax
- #'filename
- (or (%search-load-path fn)
- (syntax-violation 'include-from-path
- "file not found in path"
- x #'filename)))))
- #'(include fn)))))))
-
-(define-syntax unquote
- (lambda (x)
- (syntax-case x ()
- ((_ e)
- (syntax-violation 'unquote
- "expression not valid outside of quasiquote"
- x)))))
-
-(define-syntax unquote-splicing
- (lambda (x)
- (syntax-case x ()
- ((_ e)
- (syntax-violation 'unquote-splicing
- "expression not valid outside of quasiquote"
- x)))))
-
-(define-syntax case
- (lambda (x)
- (syntax-case x ()
- ((_ e m1 m2 ...)
- (with-syntax
- ((body (let f ((clause #'m1) (clauses #'(m2 ...)))
- (if (null? clauses)
- (syntax-case clause (else)
- ((else e1 e2 ...) #'(begin e1 e2 ...))
- (((k ...) e1 e2 ...)
- #'(if (memv t '(k ...)) (begin e1 e2 ...)))
- (_ (syntax-violation 'case "bad clause" x clause)))
- (with-syntax ((rest (f (car clauses) (cdr clauses))))
- (syntax-case clause (else)
- (((k ...) e1 e2 ...)
- #'(if (memv t '(k ...))
- (begin e1 e2 ...)
- rest))
- (_ (syntax-violation 'case "bad clause" x
- clause))))))))
- #'(let ((t e)) body))))))
-
-(define (make-variable-transformer proc)
- (if (procedure? proc)
- (let ((trans (lambda (x)
- #((macro-type . variable-transformer))
- (proc x))))
- (set-procedure-property! trans 'variable-transformer #t)
- trans)
- (error "variable transformer not a procedure" proc)))
-
-(define-syntax identifier-syntax
- (lambda (x)
- (syntax-case x (set!)
- ((_ e)
- #'(lambda (x)
- #((macro-type . identifier-syntax))
- (syntax-case x ()
- (id
- (identifier? #'id)
- #'e)
- ((_ x (... ...))
- #'(e x (... ...))))))
- ((_ (id exp1) ((set! var val) exp2))
- (and (identifier? #'id) (identifier? #'var))
- #'(make-variable-transformer
- (lambda (x)
- #((macro-type . variable-transformer))
- (syntax-case x (set!)
- ((set! var val) #'exp2)
- ((id x (... ...)) #'(exp1 x (... ...)))
- (id (identifier? #'id) #'exp1))))))))
-
-(define-syntax define*
- (lambda (x)
- (syntax-case x ()
- ((_ (id . args) b0 b1 ...)
- #'(define id (lambda* args b0 b1 ...)))
- ((_ id val) (identifier? #'x)
- #'(define id val)))))
+;;;; -*-scheme-*-
+;;;;
+;;;; Copyright (C) 2001, 2003, 2006, 2009, 2010 Free Software Foundation, Inc.
+;;;;
+;;;; This library is free software; you can redistribute it and/or
+;;;; modify it under the terms of the GNU Lesser General Public
+;;;; License as published by the Free Software Foundation; either
+;;;; version 3 of the License, or (at your option) any later version.
+;;;;
+;;;; This library is distributed in the hope that it will be useful,
+;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+;;;; Lesser General Public License for more details.
+;;;;
+;;;; You should have received a copy of the GNU Lesser General Public
+;;;; License along with this library; if not, write to the Free Software
+;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+;;;;
+\f
+
+;;; Portable implementation of syntax-case
+;;; Originally extracted from Chez Scheme Version 5.9f
+;;; Authors: R. Kent Dybvig, Oscar Waddell, Bob Hieb, Carl Bruggeman
+
+;;; Copyright (c) 1992-1997 Cadence Research Systems
+;;; Permission to copy this software, in whole or in part, to use this
+;;; software for any lawful purpose, and to redistribute this software
+;;; is granted subject to the restriction that all copies made of this
+;;; software must include this copyright notice in full. This software
+;;; is provided AS IS, with NO WARRANTY, EITHER EXPRESS OR IMPLIED,
+;;; INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY
+;;; OR FITNESS FOR ANY PARTICULAR PURPOSE. IN NO EVENT SHALL THE
+;;; AUTHORS BE LIABLE FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES OF ANY
+;;; NATURE WHATSOEVER.
+
+;;; Modified by Mikael Djurfeldt <djurfeldt@nada.kth.se> according
+;;; to the ChangeLog distributed in the same directory as this file:
+;;; 1997-08-19, 1997-09-03, 1997-09-10, 2000-08-13, 2000-08-24,
+;;; 2000-09-12, 2001-03-08
+
+;;; Modified by Andy Wingo <wingo@pobox.com> according to the Git
+;;; revision control logs corresponding to this file: 2009, 2010.
+
+
+;;; This file defines the syntax-case expander, macroexpand, and a set
+;;; of associated syntactic forms and procedures. Of these, the
+;;; following are documented in The Scheme Programming Language,
+;;; Fourth Edition (R. Kent Dybvig, MIT Press, 2009), and in the
+;;; R6RS:
+;;;
+;;; bound-identifier=?
+;;; datum->syntax
+;;; define-syntax
+;;; fluid-let-syntax
+;;; free-identifier=?
+;;; generate-temporaries
+;;; identifier?
+;;; identifier-syntax
+;;; let-syntax
+;;; letrec-syntax
+;;; syntax
+;;; syntax-case
+;;; syntax->datum
+;;; syntax-rules
+;;; with-syntax
+;;;
+;;; Additionally, the expander provides definitions for a number of core
+;;; Scheme syntactic bindings, such as `let', `lambda', and the like.
+
+;;; The remaining exports are listed below:
+;;;
+;;; (macroexpand datum)
+;;; if datum represents a valid expression, macroexpand returns an
+;;; expanded version of datum in a core language that includes no
+;;; syntactic abstractions. The core language includes begin,
+;;; define, if, lambda, letrec, quote, and set!.
+;;; (eval-when situations expr ...)
+;;; conditionally evaluates expr ... at compile-time or run-time
+;;; depending upon situations (see the Chez Scheme System Manual,
+;;; Revision 3, for a complete description)
+;;; (syntax-violation who message form [subform])
+;;; used to report errors found during expansion
+;;; ($sc-dispatch e p)
+;;; used by expanded code to handle syntax-case matching
+
+;;; This file is shipped along with an expanded version of itself,
+;;; psyntax-pp.scm, which is loaded when psyntax.scm has not yet been
+;;; compiled. In this way, psyntax bootstraps off of an expanded
+;;; version of itself.
+
+;;; This implementation of the expander sometimes uses syntactic
+;;; abstractions when procedural abstractions would suffice. For
+;;; example, we define top-wrap and top-marked? as
+;;;
+;;; (define-syntax top-wrap (identifier-syntax '((top))))
+;;; (define-syntax top-marked?
+;;; (syntax-rules ()
+;;; ((_ w) (memq 'top (wrap-marks w)))))
+;;;
+;;; rather than
+;;;
+;;; (define top-wrap '((top)))
+;;; (define top-marked?
+;;; (lambda (w) (memq 'top (wrap-marks w))))
+;;;
+;;; On the other hand, we don't do this consistently; we define
+;;; make-wrap, wrap-marks, and wrap-subst simply as
+;;;
+;;; (define make-wrap cons)
+;;; (define wrap-marks car)
+;;; (define wrap-subst cdr)
+;;;
+;;; In Chez Scheme, the syntactic and procedural forms of these
+;;; abstractions are equivalent, since the optimizer consistently
+;;; integrates constants and small procedures. This will be true of
+;;; Guile as well, once we implement a proper inliner.
+
+
+;;; Implementation notes:
+
+;;; Objects with no standard print syntax, including objects containing
+;;; cycles and syntax object, are allowed in quoted data as long as they
+;;; are contained within a syntax form or produced by datum->syntax.
+;;; Such objects are never copied.
+
+;;; All identifiers that don't have macro definitions and are not bound
+;;; lexically are assumed to be global variables.
+
+;;; Top-level definitions of macro-introduced identifiers are allowed.
+;;; This may not be appropriate for implementations in which the
+;;; model is that bindings are created by definitions, as opposed to
+;;; one in which initial values are assigned by definitions.
+
+;;; Identifiers and syntax objects are implemented as vectors for
+;;; portability. As a result, it is possible to "forge" syntax objects.
+
+;;; The implementation of generate-temporaries assumes that it is
+;;; possible to generate globally unique symbols (gensyms).
+
+;;; The source location associated with incoming expressions is tracked
+;;; via the source-properties mechanism, a weak map from expression to
+;;; source information. At times the source is separated from the
+;;; expression; see the note below about "efficiency and confusion".
+
+
+;;; Bootstrapping:
+
+;;; When changing syntax-object representations, it is necessary to support
+;;; both old and new syntax-object representations in id-var-name. It
+;;; should be sufficient to recognize old representations and treat
+;;; them as not lexically bound.
+
+
+
+(eval-when (compile)
+ (set-current-module (resolve-module '(guile))))
+
+(let ()
+ ;; Private version of and-map that handles multiple lists.
+ (define and-map*
+ (lambda (f first . rest)
+ (or (null? first)
+ (if (null? rest)
+ (let andmap ((first first))
+ (let ((x (car first)) (first (cdr first)))
+ (if (null? first)
+ (f x)
+ (and (f x) (andmap first)))))
+ (let andmap ((first first) (rest rest))
+ (let ((x (car first))
+ (xr (map car rest))
+ (first (cdr first))
+ (rest (map cdr rest)))
+ (if (null? first)
+ (apply f x xr)
+ (and (apply f x xr) (andmap first rest)))))))))
+
+ (define-syntax define-expansion-constructors
+ (lambda (x)
+ (syntax-case x ()
+ ((_)
+ (let lp ((n 0) (out '()))
+ (if (< n (vector-length %expanded-vtables))
+ (lp (1+ n)
+ (let* ((vtable (vector-ref %expanded-vtables n))
+ (stem (struct-ref vtable (+ vtable-offset-user 0)))
+ (fields (struct-ref vtable (+ vtable-offset-user 2)))
+ (sfields (map (lambda (f) (datum->syntax x f)) fields))
+ (ctor (datum->syntax x (symbol-append 'make- stem))))
+ (cons #`(define (#,ctor #,@sfields)
+ (make-struct (vector-ref %expanded-vtables #,n) 0
+ #,@sfields))
+ out)))
+ #`(begin #,@(reverse out))))))))
+
+ (define-syntax define-expansion-accessors
+ (lambda (x)
+ (syntax-case x ()
+ ((_ stem field ...)
+ (let lp ((n 0))
+ (let ((vtable (vector-ref %expanded-vtables n))
+ (stem (syntax->datum #'stem)))
+ (if (eq? (struct-ref vtable (+ vtable-offset-user 0)) stem)
+ #`(begin
+ (define (#,(datum->syntax x (symbol-append stem '?)) x)
+ (and (struct? x)
+ (eq? (struct-vtable x)
+ (vector-ref %expanded-vtables #,n))))
+ #,@(map
+ (lambda (f)
+ (let ((get (datum->syntax x (symbol-append stem '- f)))
+ (set (datum->syntax x (symbol-append 'set- stem '- f '!)))
+ (idx (list-index (struct-ref vtable
+ (+ vtable-offset-user 2))
+ f)))
+ #`(begin
+ (define (#,get x)
+ (struct-ref x #,idx))
+ (define (#,set x v)
+ (struct-set! x #,idx v)))))
+ (syntax->datum #'(field ...))))
+ (lp (1+ n)))))))))
+
+ (define-syntax define-structure
+ (lambda (x)
+ (define construct-name
+ (lambda (template-identifier . args)
+ (datum->syntax
+ template-identifier
+ (string->symbol
+ (apply string-append
+ (map (lambda (x)
+ (if (string? x)
+ x
+ (symbol->string (syntax->datum x))))
+ args))))))
+ (syntax-case x ()
+ ((_ (name id1 ...))
+ (and-map identifier? #'(name id1 ...))
+ (with-syntax
+ ((constructor (construct-name #'name "make-" #'name))
+ (predicate (construct-name #'name #'name "?"))
+ ((access ...)
+ (map (lambda (x) (construct-name x #'name "-" x))
+ #'(id1 ...)))
+ ((assign ...)
+ (map (lambda (x)
+ (construct-name x "set-" #'name "-" x "!"))
+ #'(id1 ...)))
+ (structure-length
+ (+ (length #'(id1 ...)) 1))
+ ((index ...)
+ (let f ((i 1) (ids #'(id1 ...)))
+ (if (null? ids)
+ '()
+ (cons i (f (+ i 1) (cdr ids)))))))
+ #'(begin
+ (define constructor
+ (lambda (id1 ...)
+ (vector 'name id1 ... )))
+ (define predicate
+ (lambda (x)
+ (and (vector? x)
+ (= (vector-length x) structure-length)
+ (eq? (vector-ref x 0) 'name))))
+ (define access
+ (lambda (x)
+ (vector-ref x index)))
+ ...
+ (define assign
+ (lambda (x update)
+ (vector-set! x index update)))
+ ...))))))
+
+ (let ()
+ (define-expansion-constructors)
+ (define-expansion-accessors lambda meta)
+
+ ;; hooks to nonportable run-time helpers
+ (begin
+ (define fx+ +)
+ (define fx- -)
+ (define fx= =)
+ (define fx< <)
+
+ (define top-level-eval-hook
+ (lambda (x mod)
+ (primitive-eval x)))
+
+ (define local-eval-hook
+ (lambda (x mod)
+ (primitive-eval x)))
+
+ (define-syntax gensym-hook
+ (syntax-rules ()
+ ((_) (gensym))))
+
+ (define put-global-definition-hook
+ (lambda (symbol type val)
+ (module-define! (current-module)
+ symbol
+ (make-syntax-transformer symbol type val))))
+
+ (define get-global-definition-hook
+ (lambda (symbol module)
+ (if (and (not module) (current-module))
+ (warn "module system is booted, we should have a module" symbol))
+ (let ((v (module-variable (if module
+ (resolve-module (cdr module))
+ (current-module))
+ symbol)))
+ (and v (variable-bound? v)
+ (let ((val (variable-ref v)))
+ (and (macro? val) (macro-type val)
+ (cons (macro-type val)
+ (macro-binding val)))))))))
+
+
+ (define (decorate-source e s)
+ (if (and (pair? e) s)
+ (set-source-properties! e s))
+ e)
+
+ (define (maybe-name-value! name val)
+ (if (lambda? val)
+ (let ((meta (lambda-meta val)))
+ (if (not (assq 'name meta))
+ (set-lambda-meta! val (acons 'name name meta))))))
+
+ ;; output constructors
+ (define build-void
+ (lambda (source)
+ (make-void source)))
+
+ (define build-application
+ (lambda (source fun-exp arg-exps)
+ (make-application source fun-exp arg-exps)))
+
+ (define build-conditional
+ (lambda (source test-exp then-exp else-exp)
+ (make-conditional source test-exp then-exp else-exp)))
+
+ (define build-dynlet
+ (lambda (source fluids vals body)
+ (make-dynlet source fluids vals body)))
+
+ (define build-lexical-reference
+ (lambda (type source name var)
+ (make-lexical-ref source name var)))
+
+ (define build-lexical-assignment
+ (lambda (source name var exp)
+ (maybe-name-value! name exp)
+ (make-lexical-set source name var exp)))
+
+ (define (analyze-variable mod var modref-cont bare-cont)
+ (if (not mod)
+ (bare-cont var)
+ (let ((kind (car mod))
+ (mod (cdr mod)))
+ (case kind
+ ((public) (modref-cont mod var #t))
+ ((private) (if (not (equal? mod (module-name (current-module))))
+ (modref-cont mod var #f)
+ (bare-cont var)))
+ ((bare) (bare-cont var))
+ ((hygiene) (if (and (not (equal? mod (module-name (current-module))))
+ (module-variable (resolve-module mod) var))
+ (modref-cont mod var #f)
+ (bare-cont var)))
+ (else (syntax-violation #f "bad module kind" var mod))))))
+
+ (define build-global-reference
+ (lambda (source var mod)
+ (analyze-variable
+ mod var
+ (lambda (mod var public?)
+ (make-module-ref source mod var public?))
+ (lambda (var)
+ (make-toplevel-ref source var)))))
+
+ (define build-global-assignment
+ (lambda (source var exp mod)
+ (maybe-name-value! var exp)
+ (analyze-variable
+ mod var
+ (lambda (mod var public?)
+ (make-module-set source mod var public? exp))
+ (lambda (var)
+ (make-toplevel-set source var exp)))))
+
+ (define build-global-definition
+ (lambda (source var exp)
+ (maybe-name-value! var exp)
+ (make-toplevel-define source var exp)))
+
+ (define build-simple-lambda
+ (lambda (src req rest vars meta exp)
+ (make-lambda src
+ meta
+ ;; hah, a case in which kwargs would be nice.
+ (make-lambda-case
+ ;; src req opt rest kw inits vars body else
+ src req #f rest #f '() vars exp #f))))
+
+ (define build-case-lambda
+ (lambda (src meta body)
+ (make-lambda src meta body)))
+
+ (define build-lambda-case
+ ;; req := (name ...)
+ ;; opt := (name ...) | #f
+ ;; rest := name | #f
+ ;; kw := (allow-other-keys? (keyword name var) ...) | #f
+ ;; inits: (init ...)
+ ;; vars: (sym ...)
+ ;; vars map to named arguments in the following order:
+ ;; required, optional (positional), rest, keyword.
+ ;; the body of a lambda: anything, already expanded
+ ;; else: lambda-case | #f
+ (lambda (src req opt rest kw inits vars body else-case)
+ (make-lambda-case src req opt rest kw inits vars body else-case)))
+
+ (define build-primref
+ (lambda (src name)
+ (if (equal? (module-name (current-module)) '(guile))
+ (make-toplevel-ref src name)
+ (make-module-ref src '(guile) name #f))))
+
+ (define (build-data src exp)
+ (make-const src exp))
+
+ (define build-sequence
+ (lambda (src exps)
+ (if (null? (cdr exps))
+ (car exps)
+ (make-sequence src exps))))
+
+ (define build-let
+ (lambda (src ids vars val-exps body-exp)
+ (for-each maybe-name-value! ids val-exps)
+ (if (null? vars)
+ body-exp
+ (make-let src ids vars val-exps body-exp))))
+
+ (define build-named-let
+ (lambda (src ids vars val-exps body-exp)
+ (let ((f (car vars))
+ (f-name (car ids))
+ (vars (cdr vars))
+ (ids (cdr ids)))
+ (let ((proc (build-simple-lambda src ids #f vars '() body-exp)))
+ (maybe-name-value! f-name proc)
+ (for-each maybe-name-value! ids val-exps)
+ (make-letrec
+ src #f
+ (list f-name) (list f) (list proc)
+ (build-application src (build-lexical-reference 'fun src f-name f)
+ val-exps))))))
+
+ (define build-letrec
+ (lambda (src in-order? ids vars val-exps body-exp)
+ (if (null? vars)
+ body-exp
+ (begin
+ (for-each maybe-name-value! ids val-exps)
+ (make-letrec src in-order? ids vars val-exps body-exp)))))
+
+
+ ;; FIXME: use a faster gensym
+ (define-syntax build-lexical-var
+ (syntax-rules ()
+ ((_ src id) (gensym (string-append (symbol->string id) " ")))))
+
+ (define-structure (syntax-object expression wrap module))
+
+ (define-syntax no-source (identifier-syntax #f))
+
+ (define source-annotation
+ (lambda (x)
+ (cond
+ ((syntax-object? x)
+ (source-annotation (syntax-object-expression x)))
+ ((pair? x) (let ((props (source-properties x)))
+ (if (pair? props)
+ props
+ #f)))
+ (else #f))))
+
+ (define-syntax arg-check
+ (syntax-rules ()
+ ((_ pred? e who)
+ (let ((x e))
+ (if (not (pred? x)) (syntax-violation who "invalid argument" x))))))
+
+ ;; compile-time environments
+
+ ;; wrap and environment comprise two level mapping.
+ ;; wrap : id --> label
+ ;; env : label --> <element>
+
+ ;; environments are represented in two parts: a lexical part and a global
+ ;; part. The lexical part is a simple list of associations from labels
+ ;; to bindings. The global part is implemented by
+ ;; {put,get}-global-definition-hook and associates symbols with
+ ;; bindings.
+
+ ;; global (assumed global variable) and displaced-lexical (see below)
+ ;; do not show up in any environment; instead, they are fabricated by
+ ;; lookup when it finds no other bindings.
+
+ ;; <environment> ::= ((<label> . <binding>)*)
+
+ ;; identifier bindings include a type and a value
+
+ ;; <binding> ::= (macro . <procedure>) macros
+ ;; (core . <procedure>) core forms
+ ;; (module-ref . <procedure>) @ or @@
+ ;; (begin) begin
+ ;; (define) define
+ ;; (define-syntax) define-syntax
+ ;; (local-syntax . rec?) let-syntax/letrec-syntax
+ ;; (eval-when) eval-when
+ ;; #'. (<var> . <level>) pattern variables
+ ;; (global) assumed global variable
+ ;; (lexical . <var>) lexical variables
+ ;; (displaced-lexical) displaced lexicals
+ ;; <level> ::= <nonnegative integer>
+ ;; <var> ::= variable returned by build-lexical-var
+
+ ;; a macro is a user-defined syntactic-form. a core is a system-defined
+ ;; syntactic form. begin, define, define-syntax, and eval-when are
+ ;; treated specially since they are sensitive to whether the form is
+ ;; at top-level and (except for eval-when) can denote valid internal
+ ;; definitions.
+
+ ;; a pattern variable is a variable introduced by syntax-case and can
+ ;; be referenced only within a syntax form.
+
+ ;; any identifier for which no top-level syntax definition or local
+ ;; binding of any kind has been seen is assumed to be a global
+ ;; variable.
+
+ ;; a lexical variable is a lambda- or letrec-bound variable.
+
+ ;; a displaced-lexical identifier is a lexical identifier removed from
+ ;; it's scope by the return of a syntax object containing the identifier.
+ ;; a displaced lexical can also appear when a letrec-syntax-bound
+ ;; keyword is referenced on the rhs of one of the letrec-syntax clauses.
+ ;; a displaced lexical should never occur with properly written macros.
+
+ (define-syntax make-binding
+ (syntax-rules (quote)
+ ((_ type value) (cons type value))
+ ((_ 'type) '(type))
+ ((_ type) (cons type '()))))
+ (define binding-type car)
+ (define binding-value cdr)
+
+ (define-syntax null-env (identifier-syntax '()))
+
+ (define extend-env
+ (lambda (labels bindings r)
+ (if (null? labels)
+ r
+ (extend-env (cdr labels) (cdr bindings)
+ (cons (cons (car labels) (car bindings)) r)))))
+
+ (define extend-var-env
+ ;; variant of extend-env that forms "lexical" binding
+ (lambda (labels vars r)
+ (if (null? labels)
+ r
+ (extend-var-env (cdr labels) (cdr vars)
+ (cons (cons (car labels) (make-binding 'lexical (car vars))) r)))))
+
+ ;; we use a "macros only" environment in expansion of local macro
+ ;; definitions so that their definitions can use local macros without
+ ;; attempting to use other lexical identifiers.
+ (define macros-only-env
+ (lambda (r)
+ (if (null? r)
+ '()
+ (let ((a (car r)))
+ (if (eq? (cadr a) 'macro)
+ (cons a (macros-only-env (cdr r)))
+ (macros-only-env (cdr r)))))))
+
+ (define lookup
+ ;; x may be a label or a symbol
+ ;; although symbols are usually global, we check the environment first
+ ;; anyway because a temporary binding may have been established by
+ ;; fluid-let-syntax
+ (lambda (x r mod)
+ (cond
+ ((assq x r) => cdr)
+ ((symbol? x)
+ (or (get-global-definition-hook x mod) (make-binding 'global)))
+ (else (make-binding 'displaced-lexical)))))
+
+ (define global-extend
+ (lambda (type sym val)
+ (put-global-definition-hook sym type val)))
+
+
+ ;; Conceptually, identifiers are always syntax objects. Internally,
+ ;; however, the wrap is sometimes maintained separately (a source of
+ ;; efficiency and confusion), so that symbols are also considered
+ ;; identifiers by id?. Externally, they are always wrapped.
+
+ (define nonsymbol-id?
+ (lambda (x)
+ (and (syntax-object? x)
+ (symbol? (syntax-object-expression x)))))
+
+ (define id?
+ (lambda (x)
+ (cond
+ ((symbol? x) #t)
+ ((syntax-object? x) (symbol? (syntax-object-expression x)))
+ (else #f))))
+
+ (define-syntax id-sym-name
+ (syntax-rules ()
+ ((_ e)
+ (let ((x e))
+ (if (syntax-object? x)
+ (syntax-object-expression x)
+ x)))))
+
+ (define id-sym-name&marks
+ (lambda (x w)
+ (if (syntax-object? x)
+ (values
+ (syntax-object-expression x)
+ (join-marks (wrap-marks w) (wrap-marks (syntax-object-wrap x))))
+ (values x (wrap-marks w)))))
+
+ ;; syntax object wraps
+
+ ;; <wrap> ::= ((<mark> ...) . (<subst> ...))
+ ;; <subst> ::= <shift> | <subs>
+ ;; <subs> ::= #(<old name> <label> (<mark> ...))
+ ;; <shift> ::= positive fixnum
+
+ (define make-wrap cons)
+ (define wrap-marks car)
+ (define wrap-subst cdr)
+
+ (define-syntax subst-rename? (identifier-syntax vector?))
+ (define-syntax rename-old (syntax-rules () ((_ x) (vector-ref x 0))))
+ (define-syntax rename-new (syntax-rules () ((_ x) (vector-ref x 1))))
+ (define-syntax rename-marks (syntax-rules () ((_ x) (vector-ref x 2))))
+ (define-syntax make-rename
+ (syntax-rules ()
+ ((_ old new marks) (vector old new marks))))
+
+ ;; labels must be comparable with "eq?", have read-write invariance,
+ ;; and distinct from symbols.
+ (define gen-label
+ (lambda () (symbol->string (gensym "i"))))
+
+ (define gen-labels
+ (lambda (ls)
+ (if (null? ls)
+ '()
+ (cons (gen-label) (gen-labels (cdr ls))))))
+
+ (define-structure (ribcage symnames marks labels))
+
+ (define-syntax empty-wrap (identifier-syntax '(())))
+
+ (define-syntax top-wrap (identifier-syntax '((top))))
+
+ (define-syntax top-marked?
+ (syntax-rules ()
+ ((_ w) (memq 'top (wrap-marks w)))))
+
+ ;; Marks must be comparable with "eq?" and distinct from pairs and
+ ;; the symbol top. We do not use integers so that marks will remain
+ ;; unique even across file compiles.
+
+ (define-syntax the-anti-mark (identifier-syntax #f))
+
+ (define anti-mark
+ (lambda (w)
+ (make-wrap (cons the-anti-mark (wrap-marks w))
+ (cons 'shift (wrap-subst w)))))
+
+ (define-syntax new-mark
+ (syntax-rules ()
+ ((_) (gensym "m"))))
+
+ ;; make-empty-ribcage and extend-ribcage maintain list-based ribcages for
+ ;; internal definitions, in which the ribcages are built incrementally
+ (define-syntax make-empty-ribcage
+ (syntax-rules ()
+ ((_) (make-ribcage '() '() '()))))
+
+ (define extend-ribcage!
+ ;; must receive ids with complete wraps
+ (lambda (ribcage id label)
+ (set-ribcage-symnames! ribcage
+ (cons (syntax-object-expression id)
+ (ribcage-symnames ribcage)))
+ (set-ribcage-marks! ribcage
+ (cons (wrap-marks (syntax-object-wrap id))
+ (ribcage-marks ribcage)))
+ (set-ribcage-labels! ribcage
+ (cons label (ribcage-labels ribcage)))))
+
+ ;; make-binding-wrap creates vector-based ribcages
+ (define make-binding-wrap
+ (lambda (ids labels w)
+ (if (null? ids)
+ w
+ (make-wrap
+ (wrap-marks w)
+ (cons
+ (let ((labelvec (list->vector labels)))
+ (let ((n (vector-length labelvec)))
+ (let ((symnamevec (make-vector n)) (marksvec (make-vector n)))
+ (let f ((ids ids) (i 0))
+ (if (not (null? ids))
+ (call-with-values
+ (lambda () (id-sym-name&marks (car ids) w))
+ (lambda (symname marks)
+ (vector-set! symnamevec i symname)
+ (vector-set! marksvec i marks)
+ (f (cdr ids) (fx+ i 1))))))
+ (make-ribcage symnamevec marksvec labelvec))))
+ (wrap-subst w))))))
+
+ (define smart-append
+ (lambda (m1 m2)
+ (if (null? m2)
+ m1
+ (append m1 m2))))
+
+ (define join-wraps
+ (lambda (w1 w2)
+ (let ((m1 (wrap-marks w1)) (s1 (wrap-subst w1)))
+ (if (null? m1)
+ (if (null? s1)
+ w2
+ (make-wrap
+ (wrap-marks w2)
+ (smart-append s1 (wrap-subst w2))))
+ (make-wrap
+ (smart-append m1 (wrap-marks w2))
+ (smart-append s1 (wrap-subst w2)))))))
+
+ (define join-marks
+ (lambda (m1 m2)
+ (smart-append m1 m2)))
+
+ (define same-marks?
+ (lambda (x y)
+ (or (eq? x y)
+ (and (not (null? x))
+ (not (null? y))
+ (eq? (car x) (car y))
+ (same-marks? (cdr x) (cdr y))))))
+
+ (define id-var-name
+ (lambda (id w)
+ (define-syntax first
+ (syntax-rules ()
+ ((_ e) (call-with-values (lambda () e) (lambda (x . ignore) x)))))
+ (define search
+ (lambda (sym subst marks)
+ (if (null? subst)
+ (values #f marks)
+ (let ((fst (car subst)))
+ (if (eq? fst 'shift)
+ (search sym (cdr subst) (cdr marks))
+ (let ((symnames (ribcage-symnames fst)))
+ (if (vector? symnames)
+ (search-vector-rib sym subst marks symnames fst)
+ (search-list-rib sym subst marks symnames fst))))))))
+ (define search-list-rib
+ (lambda (sym subst marks symnames ribcage)
+ (let f ((symnames symnames) (i 0))
+ (cond
+ ((null? symnames) (search sym (cdr subst) marks))
+ ((and (eq? (car symnames) sym)
+ (same-marks? marks (list-ref (ribcage-marks ribcage) i)))
+ (values (list-ref (ribcage-labels ribcage) i) marks))
+ (else (f (cdr symnames) (fx+ i 1)))))))
+ (define search-vector-rib
+ (lambda (sym subst marks symnames ribcage)
+ (let ((n (vector-length symnames)))
+ (let f ((i 0))
+ (cond
+ ((fx= i n) (search sym (cdr subst) marks))
+ ((and (eq? (vector-ref symnames i) sym)
+ (same-marks? marks (vector-ref (ribcage-marks ribcage) i)))
+ (values (vector-ref (ribcage-labels ribcage) i) marks))
+ (else (f (fx+ i 1))))))))
+ (cond
+ ((symbol? id)
+ (or (first (search id (wrap-subst w) (wrap-marks w))) id))
+ ((syntax-object? id)
+ (let ((id (syntax-object-expression id))
+ (w1 (syntax-object-wrap id)))
+ (let ((marks (join-marks (wrap-marks w) (wrap-marks w1))))
+ (call-with-values (lambda () (search id (wrap-subst w) marks))
+ (lambda (new-id marks)
+ (or new-id
+ (first (search id (wrap-subst w1) marks))
+ id))))))
+ (else (syntax-violation 'id-var-name "invalid id" id)))))
+
+ ;; free-id=? must be passed fully wrapped ids since (free-id=? x y)
+ ;; may be true even if (free-id=? (wrap x w) (wrap y w)) is not.
+
+ (define free-id=?
+ (lambda (i j)
+ (and (eq? (id-sym-name i) (id-sym-name j)) ; accelerator
+ (eq? (id-var-name i empty-wrap) (id-var-name j empty-wrap)))))
+
+ ;; bound-id=? may be passed unwrapped (or partially wrapped) ids as
+ ;; long as the missing portion of the wrap is common to both of the ids
+ ;; since (bound-id=? x y) iff (bound-id=? (wrap x w) (wrap y w))
+
+ (define bound-id=?
+ (lambda (i j)
+ (if (and (syntax-object? i) (syntax-object? j))
+ (and (eq? (syntax-object-expression i)
+ (syntax-object-expression j))
+ (same-marks? (wrap-marks (syntax-object-wrap i))
+ (wrap-marks (syntax-object-wrap j))))
+ (eq? i j))))
+
+ ;; "valid-bound-ids?" returns #t if it receives a list of distinct ids.
+ ;; valid-bound-ids? may be passed unwrapped (or partially wrapped) ids
+ ;; as long as the missing portion of the wrap is common to all of the
+ ;; ids.
+
+ (define valid-bound-ids?
+ (lambda (ids)
+ (and (let all-ids? ((ids ids))
+ (or (null? ids)
+ (and (id? (car ids))
+ (all-ids? (cdr ids)))))
+ (distinct-bound-ids? ids))))
+
+ ;; distinct-bound-ids? expects a list of ids and returns #t if there are
+ ;; no duplicates. It is quadratic on the length of the id list; long
+ ;; lists could be sorted to make it more efficient. distinct-bound-ids?
+ ;; may be passed unwrapped (or partially wrapped) ids as long as the
+ ;; missing portion of the wrap is common to all of the ids.
+
+ (define distinct-bound-ids?
+ (lambda (ids)
+ (let distinct? ((ids ids))
+ (or (null? ids)
+ (and (not (bound-id-member? (car ids) (cdr ids)))
+ (distinct? (cdr ids)))))))
+
+ (define bound-id-member?
+ (lambda (x list)
+ (and (not (null? list))
+ (or (bound-id=? x (car list))
+ (bound-id-member? x (cdr list))))))
+
+ ;; wrapping expressions and identifiers
+
+ (define wrap
+ (lambda (x w defmod)
+ (cond
+ ((and (null? (wrap-marks w)) (null? (wrap-subst w))) x)
+ ((syntax-object? x)
+ (make-syntax-object
+ (syntax-object-expression x)
+ (join-wraps w (syntax-object-wrap x))
+ (syntax-object-module x)))
+ ((null? x) x)
+ (else (make-syntax-object x w defmod)))))
+
+ (define source-wrap
+ (lambda (x w s defmod)
+ (wrap (decorate-source x s) w defmod)))
+
+ ;; expanding
+
+ (define chi-sequence
+ (lambda (body r w s mod)
+ (build-sequence s
+ (let dobody ((body body) (r r) (w w) (mod mod))
+ (if (null? body)
+ '()
+ (let ((first (chi (car body) r w mod)))
+ (cons first (dobody (cdr body) r w mod))))))))
+
+ (define chi-top-sequence
+ (lambda (body r w s m esew mod)
+ (build-sequence s
+ (let dobody ((body body) (r r) (w w) (m m) (esew esew)
+ (mod mod) (out '()))
+ (if (null? body)
+ (reverse out)
+ (dobody (cdr body) r w m esew mod
+ (cons (chi-top (car body) r w m esew mod) out)))))))
+
+ (define chi-install-global
+ (lambda (name e)
+ (build-global-definition
+ no-source
+ name
+ (build-application
+ no-source
+ (build-primref no-source 'make-syntax-transformer)
+ (list (build-data no-source name)
+ (build-data no-source 'macro)
+ e)))))
+
+ (define chi-when-list
+ (lambda (e when-list w)
+ ;; when-list is syntax'd version of list of situations
+ (let f ((when-list when-list) (situations '()))
+ (if (null? when-list)
+ situations
+ (f (cdr when-list)
+ (cons (let ((x (car when-list)))
+ (cond
+ ((free-id=? x #'compile) 'compile)
+ ((free-id=? x #'load) 'load)
+ ((free-id=? x #'eval) 'eval)
+ ((free-id=? x #'expand) 'expand)
+ (else (syntax-violation 'eval-when
+ "invalid situation"
+ e (wrap x w #f)))))
+ situations))))))
+
+ ;; syntax-type returns six values: type, value, e, w, s, and mod. The
+ ;; first two are described in the table below.
+ ;;
+ ;; type value explanation
+ ;; -------------------------------------------------------------------
+ ;; core procedure core singleton
+ ;; core-form procedure core form
+ ;; module-ref procedure @ or @@ singleton
+ ;; lexical name lexical variable reference
+ ;; global name global variable reference
+ ;; begin none begin keyword
+ ;; define none define keyword
+ ;; define-syntax none define-syntax keyword
+ ;; local-syntax rec? letrec-syntax/let-syntax keyword
+ ;; eval-when none eval-when keyword
+ ;; syntax level pattern variable
+ ;; displaced-lexical none displaced lexical identifier
+ ;; lexical-call name call to lexical variable
+ ;; global-call name call to global variable
+ ;; call none any other call
+ ;; begin-form none begin expression
+ ;; define-form id variable definition
+ ;; define-syntax-form id syntax definition
+ ;; local-syntax-form rec? syntax definition
+ ;; eval-when-form none eval-when form
+ ;; constant none self-evaluating datum
+ ;; other none anything else
+ ;;
+ ;; For define-form and define-syntax-form, e is the rhs expression.
+ ;; For all others, e is the entire form. w is the wrap for e.
+ ;; s is the source for the entire form. mod is the module for e.
+ ;;
+ ;; syntax-type expands macros and unwraps as necessary to get to
+ ;; one of the forms above. It also parses define and define-syntax
+ ;; forms, although perhaps this should be done by the consumer.
+
+ (define syntax-type
+ (lambda (e r w s rib mod for-car?)
+ (cond
+ ((symbol? e)
+ (let* ((n (id-var-name e w))
+ (b (lookup n r mod))
+ (type (binding-type b)))
+ (case type
+ ((lexical) (values type (binding-value b) e w s mod))
+ ((global) (values type n e w s mod))
+ ((macro)
+ (if for-car?
+ (values type (binding-value b) e w s mod)
+ (syntax-type (chi-macro (binding-value b) e r w s rib mod)
+ r empty-wrap s rib mod #f)))
+ (else (values type (binding-value b) e w s mod)))))
+ ((pair? e)
+ (let ((first (car e)))
+ (call-with-values
+ (lambda () (syntax-type first r w s rib mod #t))
+ (lambda (ftype fval fe fw fs fmod)
+ (case ftype
+ ((lexical)
+ (values 'lexical-call fval e w s mod))
+ ((global)
+ ;; If we got here via an (@@ ...) expansion, we need to
+ ;; make sure the fmod information is propagated back
+ ;; correctly -- hence this consing.
+ (values 'global-call (make-syntax-object fval w fmod)
+ e w s mod))
+ ((macro)
+ (syntax-type (chi-macro fval e r w s rib mod)
+ r empty-wrap s rib mod for-car?))
+ ((module-ref)
+ (call-with-values (lambda () (fval e r w))
+ (lambda (e r w s mod)
+ (syntax-type e r w s rib mod for-car?))))
+ ((core)
+ (values 'core-form fval e w s mod))
+ ((local-syntax)
+ (values 'local-syntax-form fval e w s mod))
+ ((begin)
+ (values 'begin-form #f e w s mod))
+ ((eval-when)
+ (values 'eval-when-form #f e w s mod))
+ ((define)
+ (syntax-case e ()
+ ((_ name val)
+ (id? #'name)
+ (values 'define-form #'name #'val w s mod))
+ ((_ (name . args) e1 e2 ...)
+ (and (id? #'name)
+ (valid-bound-ids? (lambda-var-list #'args)))
+ ;; need lambda here...
+ (values 'define-form (wrap #'name w mod)
+ (decorate-source
+ (cons #'lambda (wrap #'(args e1 e2 ...) w mod))
+ s)
+ empty-wrap s mod))
+ ((_ name)
+ (id? #'name)
+ (values 'define-form (wrap #'name w mod)
+ #'(if #f #f)
+ empty-wrap s mod))))
+ ((define-syntax)
+ (syntax-case e ()
+ ((_ name val)
+ (id? #'name)
+ (values 'define-syntax-form #'name
+ #'val w s mod))))
+ (else
+ (values 'call #f e w s mod)))))))
+ ((syntax-object? e)
+ (syntax-type (syntax-object-expression e)
+ r
+ (join-wraps w (syntax-object-wrap e))
+ (or (source-annotation e) s) rib
+ (or (syntax-object-module e) mod) for-car?))
+ ((self-evaluating? e) (values 'constant #f e w s mod))
+ (else (values 'other #f e w s mod)))))
+
+ (define chi-top
+ (lambda (e r w m esew mod)
+ (define-syntax eval-if-c&e
+ (syntax-rules ()
+ ((_ m e mod)
+ (let ((x e))
+ (if (eq? m 'c&e) (top-level-eval-hook x mod))
+ x))))
+ (call-with-values
+ (lambda () (syntax-type e r w (source-annotation e) #f mod #f))
+ (lambda (type value e w s mod)
+ (case type
+ ((begin-form)
+ (syntax-case e ()
+ ((_) (chi-void))
+ ((_ e1 e2 ...)
+ (chi-top-sequence #'(e1 e2 ...) r w s m esew mod))))
+ ((local-syntax-form)
+ (chi-local-syntax value e r w s mod
+ (lambda (body r w s mod)
+ (chi-top-sequence body r w s m esew mod))))
+ ((eval-when-form)
+ (syntax-case e ()
+ ((_ (x ...) e1 e2 ...)
+ (let ((when-list (chi-when-list e #'(x ...) w))
+ (body #'(e1 e2 ...)))
+ (cond
+ ((eq? m 'e)
+ (if (memq 'eval when-list)
+ (chi-top-sequence body r w s
+ (if (memq 'expand when-list) 'c&e 'e)
+ '(eval)
+ mod)
+ (begin
+ (if (memq 'expand when-list)
+ (top-level-eval-hook
+ (chi-top-sequence body r w s 'e '(eval) mod)
+ mod))
+ (chi-void))))
+ ((memq 'load when-list)
+ (if (or (memq 'compile when-list)
+ (memq 'expand when-list)
+ (and (eq? m 'c&e) (memq 'eval when-list)))
+ (chi-top-sequence body r w s 'c&e '(compile load) mod)
+ (if (memq m '(c c&e))
+ (chi-top-sequence body r w s 'c '(load) mod)
+ (chi-void))))
+ ((or (memq 'compile when-list)
+ (memq 'expand when-list)
+ (and (eq? m 'c&e) (memq 'eval when-list)))
+ (top-level-eval-hook
+ (chi-top-sequence body r w s 'e '(eval) mod)
+ mod)
+ (chi-void))
+ (else (chi-void)))))))
+ ((define-syntax-form)
+ (let ((n (id-var-name value w)) (r (macros-only-env r)))
+ (case m
+ ((c)
+ (if (memq 'compile esew)
+ (let ((e (chi-install-global n (chi e r w mod))))
+ (top-level-eval-hook e mod)
+ (if (memq 'load esew) e (chi-void)))
+ (if (memq 'load esew)
+ (chi-install-global n (chi e r w mod))
+ (chi-void))))
+ ((c&e)
+ (let ((e (chi-install-global n (chi e r w mod))))
+ (top-level-eval-hook e mod)
+ e))
+ (else
+ (if (memq 'eval esew)
+ (top-level-eval-hook
+ (chi-install-global n (chi e r w mod))
+ mod))
+ (chi-void)))))
+ ((define-form)
+ (let* ((n (id-var-name value w))
+ ;; Lookup the name in the module of the define form.
+ (type (binding-type (lookup n r mod))))
+ (case type
+ ((global core macro module-ref)
+ ;; affect compile-time environment (once we have booted)
+ (if (and (memq m '(c c&e))
+ (not (module-local-variable (current-module) n))
+ (current-module))
+ (let ((old (module-variable (current-module) n)))
+ ;; use value of the same-named imported variable, if
+ ;; any
+ (module-define! (current-module) n
+ (if (variable? old)
+ (variable-ref old)
+ #f))))
+ (eval-if-c&e m
+ (build-global-definition s n (chi e r w mod))
+ mod))
+ ((displaced-lexical)
+ (syntax-violation #f "identifier out of context"
+ e (wrap value w mod)))
+ (else
+ (syntax-violation #f "cannot define keyword at top level"
+ e (wrap value w mod))))))
+ (else (eval-if-c&e m (chi-expr type value e r w s mod) mod)))))))
+
+ (define chi
+ (lambda (e r w mod)
+ (call-with-values
+ (lambda () (syntax-type e r w (source-annotation e) #f mod #f))
+ (lambda (type value e w s mod)
+ (chi-expr type value e r w s mod)))))
+
+ (define chi-expr
+ (lambda (type value e r w s mod)
+ (case type
+ ((lexical)
+ (build-lexical-reference 'value s e value))
+ ((core core-form)
+ ;; apply transformer
+ (value e r w s mod))
+ ((module-ref)
+ (call-with-values (lambda () (value e r w))
+ (lambda (e r w s mod)
+ (chi e r w mod))))
+ ((lexical-call)
+ (chi-application
+ (let ((id (car e)))
+ (build-lexical-reference 'fun (source-annotation id)
+ (if (syntax-object? id)
+ (syntax->datum id)
+ id)
+ value))
+ e r w s mod))
+ ((global-call)
+ (chi-application
+ (build-global-reference (source-annotation (car e))
+ (if (syntax-object? value)
+ (syntax-object-expression value)
+ value)
+ (if (syntax-object? value)
+ (syntax-object-module value)
+ mod))
+ e r w s mod))
+ ((constant) (build-data s (strip (source-wrap e w s mod) empty-wrap)))
+ ((global) (build-global-reference s value mod))
+ ((call) (chi-application (chi (car e) r w mod) e r w s mod))
+ ((begin-form)
+ (syntax-case e ()
+ ((_ e1 e2 ...) (chi-sequence #'(e1 e2 ...) r w s mod))))
+ ((local-syntax-form)
+ (chi-local-syntax value e r w s mod chi-sequence))
+ ((eval-when-form)
+ (syntax-case e ()
+ ((_ (x ...) e1 e2 ...)
+ (let ((when-list (chi-when-list e #'(x ...) w)))
+ (if (memq 'eval when-list)
+ (chi-sequence #'(e1 e2 ...) r w s mod)
+ (chi-void))))))
+ ((define-form define-syntax-form)
+ (syntax-violation #f "definition in expression context"
+ e (wrap value w mod)))
+ ((syntax)
+ (syntax-violation #f "reference to pattern variable outside syntax form"
+ (source-wrap e w s mod)))
+ ((displaced-lexical)
+ (syntax-violation #f "reference to identifier outside its scope"
+ (source-wrap e w s mod)))
+ (else (syntax-violation #f "unexpected syntax"
+ (source-wrap e w s mod))))))
+
+ (define chi-application
+ (lambda (x e r w s mod)
+ (syntax-case e ()
+ ((e0 e1 ...)
+ (build-application s x
+ (map (lambda (e) (chi e r w mod)) #'(e1 ...)))))))
+
+ ;; (What follows is my interpretation of what's going on here -- Andy)
+ ;;
+ ;; A macro takes an expression, a tree, the leaves of which are identifiers
+ ;; and datums. Identifiers are symbols along with a wrap and a module. For
+ ;; efficiency, subtrees that share wraps and modules may be grouped as one
+ ;; syntax object.
+ ;;
+ ;; Going into the expansion, the expression is given an anti-mark, which
+ ;; logically propagates to all leaves. Then, in the new expression returned
+ ;; from the transfomer, if we see an expression with an anti-mark, we know it
+ ;; pertains to the original expression; conversely, expressions without the
+ ;; anti-mark are known to be introduced by the transformer.
+ ;;
+ ;; OK, good until now. We know this algorithm does lexical scoping
+ ;; appropriately because it's widely known in the literature, and psyntax is
+ ;; widely used. But what about modules? Here we're on our own. What we do is
+ ;; to mark the module of expressions produced by a macro as pertaining to the
+ ;; module that was current when the macro was defined -- that is, free
+ ;; identifiers introduced by a macro are scoped in the macro's module, not in
+ ;; the expansion's module. Seems to work well.
+ ;;
+ ;; The only wrinkle is when we want a macro to expand to code in another
+ ;; module, as is the case for the r6rs `library' form -- the body expressions
+ ;; should be scoped relative the the new module, the one defined by the macro.
+ ;; For that, use `(@@ mod-name body)'.
+ ;;
+ ;; Part of the macro output will be from the site of the macro use and part
+ ;; from the macro definition. We allow source information from the macro use
+ ;; to pass through, but we annotate the parts coming from the macro with the
+ ;; source location information corresponding to the macro use. It would be
+ ;; really nice if we could also annotate introduced expressions with the
+ ;; locations corresponding to the macro definition, but that is not yet
+ ;; possible.
+ (define chi-macro
+ (lambda (p e r w s rib mod)
+ (define rebuild-macro-output
+ (lambda (x m)
+ (cond ((pair? x)
+ (decorate-source
+ (cons (rebuild-macro-output (car x) m)
+ (rebuild-macro-output (cdr x) m))
+ s))
+ ((syntax-object? x)
+ (let ((w (syntax-object-wrap x)))
+ (let ((ms (wrap-marks w)) (s (wrap-subst w)))
+ (if (and (pair? ms) (eq? (car ms) the-anti-mark))
+ ;; output is from original text
+ (make-syntax-object
+ (syntax-object-expression x)
+ (make-wrap (cdr ms) (if rib (cons rib (cdr s)) (cdr s)))
+ (syntax-object-module x))
+ ;; output introduced by macro
+ (make-syntax-object
+ (decorate-source (syntax-object-expression x) s)
+ (make-wrap (cons m ms)
+ (if rib
+ (cons rib (cons 'shift s))
+ (cons 'shift s)))
+ (syntax-object-module x))))))
+
+ ((vector? x)
+ (let* ((n (vector-length x))
+ (v (decorate-source (make-vector n) x)))
+ (do ((i 0 (fx+ i 1)))
+ ((fx= i n) v)
+ (vector-set! v i
+ (rebuild-macro-output (vector-ref x i) m)))))
+ ((symbol? x)
+ (syntax-violation #f "encountered raw symbol in macro output"
+ (source-wrap e w (wrap-subst w) mod) x))
+ (else (decorate-source x s)))))
+ (rebuild-macro-output (p (source-wrap e (anti-mark w) s mod))
+ (new-mark))))
+
+ (define chi-body
+ ;; In processing the forms of the body, we create a new, empty wrap.
+ ;; This wrap is augmented (destructively) each time we discover that
+ ;; the next form is a definition. This is done:
+ ;;
+ ;; (1) to allow the first nondefinition form to be a call to
+ ;; one of the defined ids even if the id previously denoted a
+ ;; definition keyword or keyword for a macro expanding into a
+ ;; definition;
+ ;; (2) to prevent subsequent definition forms (but unfortunately
+ ;; not earlier ones) and the first nondefinition form from
+ ;; confusing one of the bound identifiers for an auxiliary
+ ;; keyword; and
+ ;; (3) so that we do not need to restart the expansion of the
+ ;; first nondefinition form, which is problematic anyway
+ ;; since it might be the first element of a begin that we
+ ;; have just spliced into the body (meaning if we restarted,
+ ;; we'd really need to restart with the begin or the macro
+ ;; call that expanded into the begin, and we'd have to give
+ ;; up allowing (begin <defn>+ <expr>+), which is itself
+ ;; problematic since we don't know if a begin contains only
+ ;; definitions until we've expanded it).
+ ;;
+ ;; Before processing the body, we also create a new environment
+ ;; containing a placeholder for the bindings we will add later and
+ ;; associate this environment with each form. In processing a
+ ;; let-syntax or letrec-syntax, the associated environment may be
+ ;; augmented with local keyword bindings, so the environment may
+ ;; be different for different forms in the body. Once we have
+ ;; gathered up all of the definitions, we evaluate the transformer
+ ;; expressions and splice into r at the placeholder the new variable
+ ;; and keyword bindings. This allows let-syntax or letrec-syntax
+ ;; forms local to a portion or all of the body to shadow the
+ ;; definition bindings.
+ ;;
+ ;; Subforms of a begin, let-syntax, or letrec-syntax are spliced
+ ;; into the body.
+ ;;
+ ;; outer-form is fully wrapped w/source
+ (lambda (body outer-form r w mod)
+ (let* ((r (cons '("placeholder" . (placeholder)) r))
+ (ribcage (make-empty-ribcage))
+ (w (make-wrap (wrap-marks w) (cons ribcage (wrap-subst w)))))
+ (let parse ((body (map (lambda (x) (cons r (wrap x w mod))) body))
+ (ids '()) (labels '())
+ (var-ids '()) (vars '()) (vals '()) (bindings '()))
+ (if (null? body)
+ (syntax-violation #f "no expressions in body" outer-form)
+ (let ((e (cdar body)) (er (caar body)))
+ (call-with-values
+ (lambda () (syntax-type e er empty-wrap (source-annotation er) ribcage mod #f))
+ (lambda (type value e w s mod)
+ (case type
+ ((define-form)
+ (let ((id (wrap value w mod)) (label (gen-label)))
+ (let ((var (gen-var id)))
+ (extend-ribcage! ribcage id label)
+ (parse (cdr body)
+ (cons id ids) (cons label labels)
+ (cons id var-ids)
+ (cons var vars) (cons (cons er (wrap e w mod)) vals)
+ (cons (make-binding 'lexical var) bindings)))))
+ ((define-syntax-form)
+ (let ((id (wrap value w mod)) (label (gen-label)))
+ (extend-ribcage! ribcage id label)
+ (parse (cdr body)
+ (cons id ids) (cons label labels)
+ var-ids vars vals
+ (cons (make-binding 'macro (cons er (wrap e w mod)))
+ bindings))))
+ ((begin-form)
+ (syntax-case e ()
+ ((_ e1 ...)
+ (parse (let f ((forms #'(e1 ...)))
+ (if (null? forms)
+ (cdr body)
+ (cons (cons er (wrap (car forms) w mod))
+ (f (cdr forms)))))
+ ids labels var-ids vars vals bindings))))
+ ((local-syntax-form)
+ (chi-local-syntax value e er w s mod
+ (lambda (forms er w s mod)
+ (parse (let f ((forms forms))
+ (if (null? forms)
+ (cdr body)
+ (cons (cons er (wrap (car forms) w mod))
+ (f (cdr forms)))))
+ ids labels var-ids vars vals bindings))))
+ (else ; found a non-definition
+ (if (null? ids)
+ (build-sequence no-source
+ (map (lambda (x)
+ (chi (cdr x) (car x) empty-wrap mod))
+ (cons (cons er (source-wrap e w s mod))
+ (cdr body))))
+ (begin
+ (if (not (valid-bound-ids? ids))
+ (syntax-violation
+ #f "invalid or duplicate identifier in definition"
+ outer-form))
+ (let loop ((bs bindings) (er-cache #f) (r-cache #f))
+ (if (not (null? bs))
+ (let* ((b (car bs)))
+ (if (eq? (car b) 'macro)
+ (let* ((er (cadr b))
+ (r-cache
+ (if (eq? er er-cache)
+ r-cache
+ (macros-only-env er))))
+ (set-cdr! b
+ (eval-local-transformer
+ (chi (cddr b) r-cache empty-wrap mod)
+ mod))
+ (loop (cdr bs) er r-cache))
+ (loop (cdr bs) er-cache r-cache)))))
+ (set-cdr! r (extend-env labels bindings (cdr r)))
+ (build-letrec no-source #t
+ (reverse (map syntax->datum var-ids))
+ (reverse vars)
+ (map (lambda (x)
+ (chi (cdr x) (car x) empty-wrap mod))
+ (reverse vals))
+ (build-sequence no-source
+ (map (lambda (x)
+ (chi (cdr x) (car x) empty-wrap mod))
+ (cons (cons er (source-wrap e w s mod))
+ (cdr body)))))))))))))))))
+
+ (define chi-local-syntax
+ (lambda (rec? e r w s mod k)
+ (syntax-case e ()
+ ((_ ((id val) ...) e1 e2 ...)
+ (let ((ids #'(id ...)))
+ (if (not (valid-bound-ids? ids))
+ (syntax-violation #f "duplicate bound keyword" e)
+ (let ((labels (gen-labels ids)))
+ (let ((new-w (make-binding-wrap ids labels w)))
+ (k #'(e1 e2 ...)
+ (extend-env
+ labels
+ (let ((w (if rec? new-w w))
+ (trans-r (macros-only-env r)))
+ (map (lambda (x)
+ (make-binding 'macro
+ (eval-local-transformer
+ (chi x trans-r w mod)
+ mod)))
+ #'(val ...)))
+ r)
+ new-w
+ s
+ mod))))))
+ (_ (syntax-violation #f "bad local syntax definition"
+ (source-wrap e w s mod))))))
+
+ (define eval-local-transformer
+ (lambda (expanded mod)
+ (let ((p (local-eval-hook expanded mod)))
+ (if (procedure? p)
+ p
+ (syntax-violation #f "nonprocedure transformer" p)))))
+
+ (define chi-void
+ (lambda ()
+ (build-void no-source)))
+
+ (define ellipsis?
+ (lambda (x)
+ (and (nonsymbol-id? x)
+ (free-id=? x #'(... ...)))))
+
+ (define lambda-formals
+ (lambda (orig-args)
+ (define (req args rreq)
+ (syntax-case args ()
+ (()
+ (check (reverse rreq) #f))
+ ((a . b) (id? #'a)
+ (req #'b (cons #'a rreq)))
+ (r (id? #'r)
+ (check (reverse rreq) #'r))
+ (else
+ (syntax-violation 'lambda "invalid argument list" orig-args args))))
+ (define (check req rest)
+ (cond
+ ((distinct-bound-ids? (if rest (cons rest req) req))
+ (values req #f rest #f))
+ (else
+ (syntax-violation 'lambda "duplicate identifier in argument list"
+ orig-args))))
+ (req orig-args '())))
+
+ (define chi-simple-lambda
+ (lambda (e r w s mod req rest meta body)
+ (let* ((ids (if rest (append req (list rest)) req))
+ (vars (map gen-var ids))
+ (labels (gen-labels ids)))
+ (build-simple-lambda
+ s
+ (map syntax->datum req) (and rest (syntax->datum rest)) vars
+ meta
+ (chi-body body (source-wrap e w s mod)
+ (extend-var-env labels vars r)
+ (make-binding-wrap ids labels w)
+ mod)))))
+
+ (define lambda*-formals
+ (lambda (orig-args)
+ (define (req args rreq)
+ (syntax-case args ()
+ (()
+ (check (reverse rreq) '() #f '()))
+ ((a . b) (id? #'a)
+ (req #'b (cons #'a rreq)))
+ ((a . b) (eq? (syntax->datum #'a) #:optional)
+ (opt #'b (reverse rreq) '()))
+ ((a . b) (eq? (syntax->datum #'a) #:key)
+ (key #'b (reverse rreq) '() '()))
+ ((a b) (eq? (syntax->datum #'a) #:rest)
+ (rest #'b (reverse rreq) '() '()))
+ (r (id? #'r)
+ (rest #'r (reverse rreq) '() '()))
+ (else
+ (syntax-violation 'lambda* "invalid argument list" orig-args args))))
+ (define (opt args req ropt)
+ (syntax-case args ()
+ (()
+ (check req (reverse ropt) #f '()))
+ ((a . b) (id? #'a)
+ (opt #'b req (cons #'(a #f) ropt)))
+ (((a init) . b) (id? #'a)
+ (opt #'b req (cons #'(a init) ropt)))
+ ((a . b) (eq? (syntax->datum #'a) #:key)
+ (key #'b req (reverse ropt) '()))
+ ((a b) (eq? (syntax->datum #'a) #:rest)
+ (rest #'b req (reverse ropt) '()))
+ (r (id? #'r)
+ (rest #'r req (reverse ropt) '()))
+ (else
+ (syntax-violation 'lambda* "invalid optional argument list"
+ orig-args args))))
+ (define (key args req opt rkey)
+ (syntax-case args ()
+ (()
+ (check req opt #f (cons #f (reverse rkey))))
+ ((a . b) (id? #'a)
+ (with-syntax ((k (symbol->keyword (syntax->datum #'a))))
+ (key #'b req opt (cons #'(k a #f) rkey))))
+ (((a init) . b) (id? #'a)
+ (with-syntax ((k (symbol->keyword (syntax->datum #'a))))
+ (key #'b req opt (cons #'(k a init) rkey))))
+ (((a init k) . b) (and (id? #'a)
+ (keyword? (syntax->datum #'k)))
+ (key #'b req opt (cons #'(k a init) rkey)))
+ ((aok) (eq? (syntax->datum #'aok) #:allow-other-keys)
+ (check req opt #f (cons #t (reverse rkey))))
+ ((aok a b) (and (eq? (syntax->datum #'aok) #:allow-other-keys)
+ (eq? (syntax->datum #'a) #:rest))
+ (rest #'b req opt (cons #t (reverse rkey))))
+ ((aok . r) (and (eq? (syntax->datum #'aok) #:allow-other-keys)
+ (id? #'r))
+ (rest #'r req opt (cons #t (reverse rkey))))
+ ((a b) (eq? (syntax->datum #'a) #:rest)
+ (rest #'b req opt (cons #f (reverse rkey))))
+ (r (id? #'r)
+ (rest #'r req opt (cons #f (reverse rkey))))
+ (else
+ (syntax-violation 'lambda* "invalid keyword argument list"
+ orig-args args))))
+ (define (rest args req opt kw)
+ (syntax-case args ()
+ (r (id? #'r)
+ (check req opt #'r kw))
+ (else
+ (syntax-violation 'lambda* "invalid rest argument"
+ orig-args args))))
+ (define (check req opt rest kw)
+ (cond
+ ((distinct-bound-ids?
+ (append req (map car opt) (if rest (list rest) '())
+ (if (pair? kw) (map cadr (cdr kw)) '())))
+ (values req opt rest kw))
+ (else
+ (syntax-violation 'lambda* "duplicate identifier in argument list"
+ orig-args))))
+ (req orig-args '())))
+
+ (define chi-lambda-case
+ (lambda (e r w s mod get-formals clauses)
+ (define (expand-req req opt rest kw body)
+ (let ((vars (map gen-var req))
+ (labels (gen-labels req)))
+ (let ((r* (extend-var-env labels vars r))
+ (w* (make-binding-wrap req labels w)))
+ (expand-opt (map syntax->datum req)
+ opt rest kw body (reverse vars) r* w* '() '()))))
+ (define (expand-opt req opt rest kw body vars r* w* out inits)
+ (cond
+ ((pair? opt)
+ (syntax-case (car opt) ()
+ ((id i)
+ (let* ((v (gen-var #'id))
+ (l (gen-labels (list v)))
+ (r** (extend-var-env l (list v) r*))
+ (w** (make-binding-wrap (list #'id) l w*)))
+ (expand-opt req (cdr opt) rest kw body (cons v vars)
+ r** w** (cons (syntax->datum #'id) out)
+ (cons (chi #'i r* w* mod) inits))))))
+ (rest
+ (let* ((v (gen-var rest))
+ (l (gen-labels (list v)))
+ (r* (extend-var-env l (list v) r*))
+ (w* (make-binding-wrap (list rest) l w*)))
+ (expand-kw req (if (pair? out) (reverse out) #f)
+ (syntax->datum rest)
+ (if (pair? kw) (cdr kw) kw)
+ body (cons v vars) r* w*
+ (if (pair? kw) (car kw) #f)
+ '() inits)))
+ (else
+ (expand-kw req (if (pair? out) (reverse out) #f) #f
+ (if (pair? kw) (cdr kw) kw)
+ body vars r* w*
+ (if (pair? kw) (car kw) #f)
+ '() inits))))
+ (define (expand-kw req opt rest kw body vars r* w* aok out inits)
+ (cond
+ ((pair? kw)
+ (syntax-case (car kw) ()
+ ((k id i)
+ (let* ((v (gen-var #'id))
+ (l (gen-labels (list v)))
+ (r** (extend-var-env l (list v) r*))
+ (w** (make-binding-wrap (list #'id) l w*)))
+ (expand-kw req opt rest (cdr kw) body (cons v vars)
+ r** w** aok
+ (cons (list (syntax->datum #'k)
+ (syntax->datum #'id)
+ v)
+ out)
+ (cons (chi #'i r* w* mod) inits))))))
+ (else
+ (expand-body req opt rest
+ (if (or aok (pair? out)) (cons aok (reverse out)) #f)
+ body (reverse vars) r* w* (reverse inits) '()))))
+ (define (expand-body req opt rest kw body vars r* w* inits meta)
+ (syntax-case body ()
+ ((docstring e1 e2 ...) (string? (syntax->datum #'docstring))
+ (expand-body req opt rest kw #'(e1 e2 ...) vars r* w* inits
+ (append meta
+ `((documentation
+ . ,(syntax->datum #'docstring))))))
+ ((#((k . v) ...) e1 e2 ...)
+ (expand-body req opt rest kw #'(e1 e2 ...) vars r* w* inits
+ (append meta (syntax->datum #'((k . v) ...)))))
+ ((e1 e2 ...)
+ (values meta req opt rest kw inits vars
+ (chi-body #'(e1 e2 ...) (source-wrap e w s mod)
+ r* w* mod)))))
+
+ (syntax-case clauses ()
+ (() (values '() #f))
+ (((args e1 e2 ...) (args* e1* e2* ...) ...)
+ (call-with-values (lambda () (get-formals #'args))
+ (lambda (req opt rest kw)
+ (call-with-values (lambda ()
+ (expand-req req opt rest kw #'(e1 e2 ...)))
+ (lambda (meta req opt rest kw inits vars body)
+ (call-with-values
+ (lambda ()
+ (chi-lambda-case e r w s mod get-formals
+ #'((args* e1* e2* ...) ...)))
+ (lambda (meta* else*)
+ (values
+ (append meta meta*)
+ (build-lambda-case s req opt rest kw inits vars
+ body else*))))))))))))
+
+ ;; data
+
+ ;; strips syntax-objects down to top-wrap
+ ;;
+ ;; since only the head of a list is annotated by the reader, not each pair
+ ;; in the spine, we also check for pairs whose cars are annotated in case
+ ;; we've been passed the cdr of an annotated list
+
+ (define strip
+ (lambda (x w)
+ (if (top-marked? w)
+ x
+ (let f ((x x))
+ (cond
+ ((syntax-object? x)
+ (strip (syntax-object-expression x) (syntax-object-wrap x)))
+ ((pair? x)
+ (let ((a (f (car x))) (d (f (cdr x))))
+ (if (and (eq? a (car x)) (eq? d (cdr x)))
+ x
+ (cons a d))))
+ ((vector? x)
+ (let ((old (vector->list x)))
+ (let ((new (map f old)))
+ (if (and-map* eq? old new) x (list->vector new)))))
+ (else x))))))
+
+ ;; lexical variables
+
+ (define gen-var
+ (lambda (id)
+ (let ((id (if (syntax-object? id) (syntax-object-expression id) id)))
+ (build-lexical-var no-source id))))
+
+ ;; appears to return a reversed list
+ (define lambda-var-list
+ (lambda (vars)
+ (let lvl ((vars vars) (ls '()) (w empty-wrap))
+ (cond
+ ((pair? vars) (lvl (cdr vars) (cons (wrap (car vars) w #f) ls) w))
+ ((id? vars) (cons (wrap vars w #f) ls))
+ ((null? vars) ls)
+ ((syntax-object? vars)
+ (lvl (syntax-object-expression vars)
+ ls
+ (join-wraps w (syntax-object-wrap vars))))
+ ;; include anything else to be caught by subsequent error
+ ;; checking
+ (else (cons vars ls))))))
+
+ ;; core transformers
+
+ (global-extend 'local-syntax 'letrec-syntax #t)
+ (global-extend 'local-syntax 'let-syntax #f)
+
+ (global-extend 'core 'fluid-let-syntax
+ (lambda (e r w s mod)
+ (syntax-case e ()
+ ((_ ((var val) ...) e1 e2 ...)
+ (valid-bound-ids? #'(var ...))
+ (let ((names (map (lambda (x) (id-var-name x w)) #'(var ...))))
+ (for-each
+ (lambda (id n)
+ (case (binding-type (lookup n r mod))
+ ((displaced-lexical)
+ (syntax-violation 'fluid-let-syntax
+ "identifier out of context"
+ e
+ (source-wrap id w s mod)))))
+ #'(var ...)
+ names)
+ (chi-body
+ #'(e1 e2 ...)
+ (source-wrap e w s mod)
+ (extend-env
+ names
+ (let ((trans-r (macros-only-env r)))
+ (map (lambda (x)
+ (make-binding 'macro
+ (eval-local-transformer (chi x trans-r w mod)
+ mod)))
+ #'(val ...)))
+ r)
+ w
+ mod)))
+ (_ (syntax-violation 'fluid-let-syntax "bad syntax"
+ (source-wrap e w s mod))))))
+
+ (global-extend 'core 'quote
+ (lambda (e r w s mod)
+ (syntax-case e ()
+ ((_ e) (build-data s (strip #'e w)))
+ (_ (syntax-violation 'quote "bad syntax"
+ (source-wrap e w s mod))))))
+
+ (global-extend 'core 'syntax
+ (let ()
+ (define gen-syntax
+ (lambda (src e r maps ellipsis? mod)
+ (if (id? e)
+ (let ((label (id-var-name e empty-wrap)))
+ ;; Mod does not matter, we are looking to see if
+ ;; the id is lexical syntax.
+ (let ((b (lookup label r mod)))
+ (if (eq? (binding-type b) 'syntax)
+ (call-with-values
+ (lambda ()
+ (let ((var.lev (binding-value b)))
+ (gen-ref src (car var.lev) (cdr var.lev) maps)))
+ (lambda (var maps) (values `(ref ,var) maps)))
+ (if (ellipsis? e)
+ (syntax-violation 'syntax "misplaced ellipsis" src)
+ (values `(quote ,e) maps)))))
+ (syntax-case e ()
+ ((dots e)
+ (ellipsis? #'dots)
+ (gen-syntax src #'e r maps (lambda (x) #f) mod))
+ ((x dots . y)
+ ;; this could be about a dozen lines of code, except that we
+ ;; choose to handle #'(x ... ...) forms
+ (ellipsis? #'dots)
+ (let f ((y #'y)
+ (k (lambda (maps)
+ (call-with-values
+ (lambda ()
+ (gen-syntax src #'x r
+ (cons '() maps) ellipsis? mod))
+ (lambda (x maps)
+ (if (null? (car maps))
+ (syntax-violation 'syntax "extra ellipsis"
+ src)
+ (values (gen-map x (car maps))
+ (cdr maps))))))))
+ (syntax-case y ()
+ ((dots . y)
+ (ellipsis? #'dots)
+ (f #'y
+ (lambda (maps)
+ (call-with-values
+ (lambda () (k (cons '() maps)))
+ (lambda (x maps)
+ (if (null? (car maps))
+ (syntax-violation 'syntax "extra ellipsis" src)
+ (values (gen-mappend x (car maps))
+ (cdr maps))))))))
+ (_ (call-with-values
+ (lambda () (gen-syntax src y r maps ellipsis? mod))
+ (lambda (y maps)
+ (call-with-values
+ (lambda () (k maps))
+ (lambda (x maps)
+ (values (gen-append x y) maps)))))))))
+ ((x . y)
+ (call-with-values
+ (lambda () (gen-syntax src #'x r maps ellipsis? mod))
+ (lambda (x maps)
+ (call-with-values
+ (lambda () (gen-syntax src #'y r maps ellipsis? mod))
+ (lambda (y maps) (values (gen-cons x y) maps))))))
+ (#(e1 e2 ...)
+ (call-with-values
+ (lambda ()
+ (gen-syntax src #'(e1 e2 ...) r maps ellipsis? mod))
+ (lambda (e maps) (values (gen-vector e) maps))))
+ (_ (values `(quote ,e) maps))))))
+
+ (define gen-ref
+ (lambda (src var level maps)
+ (if (fx= level 0)
+ (values var maps)
+ (if (null? maps)
+ (syntax-violation 'syntax "missing ellipsis" src)
+ (call-with-values
+ (lambda () (gen-ref src var (fx- level 1) (cdr maps)))
+ (lambda (outer-var outer-maps)
+ (let ((b (assq outer-var (car maps))))
+ (if b
+ (values (cdr b) maps)
+ (let ((inner-var (gen-var 'tmp)))
+ (values inner-var
+ (cons (cons (cons outer-var inner-var)
+ (car maps))
+ outer-maps)))))))))))
+
+ (define gen-mappend
+ (lambda (e map-env)
+ `(apply (primitive append) ,(gen-map e map-env))))
+
+ (define gen-map
+ (lambda (e map-env)
+ (let ((formals (map cdr map-env))
+ (actuals (map (lambda (x) `(ref ,(car x))) map-env)))
+ (cond
+ ((eq? (car e) 'ref)
+ ;; identity map equivalence:
+ ;; (map (lambda (x) x) y) == y
+ (car actuals))
+ ((and-map
+ (lambda (x) (and (eq? (car x) 'ref) (memq (cadr x) formals)))
+ (cdr e))
+ ;; eta map equivalence:
+ ;; (map (lambda (x ...) (f x ...)) y ...) == (map f y ...)
+ `(map (primitive ,(car e))
+ ,@(map (let ((r (map cons formals actuals)))
+ (lambda (x) (cdr (assq (cadr x) r))))
+ (cdr e))))
+ (else `(map (lambda ,formals ,e) ,@actuals))))))
+
+ (define gen-cons
+ (lambda (x y)
+ (case (car y)
+ ((quote)
+ (if (eq? (car x) 'quote)
+ `(quote (,(cadr x) . ,(cadr y)))
+ (if (eq? (cadr y) '())
+ `(list ,x)
+ `(cons ,x ,y))))
+ ((list) `(list ,x ,@(cdr y)))
+ (else `(cons ,x ,y)))))
+
+ (define gen-append
+ (lambda (x y)
+ (if (equal? y '(quote ()))
+ x
+ `(append ,x ,y))))
+
+ (define gen-vector
+ (lambda (x)
+ (cond
+ ((eq? (car x) 'list) `(vector ,@(cdr x)))
+ ((eq? (car x) 'quote) `(quote #(,@(cadr x))))
+ (else `(list->vector ,x)))))
+
+
+ (define regen
+ (lambda (x)
+ (case (car x)
+ ((ref) (build-lexical-reference 'value no-source (cadr x) (cadr x)))
+ ((primitive) (build-primref no-source (cadr x)))
+ ((quote) (build-data no-source (cadr x)))
+ ((lambda)
+ (if (list? (cadr x))
+ (build-simple-lambda no-source (cadr x) #f (cadr x) '() (regen (caddr x)))
+ (error "how did we get here" x)))
+ (else (build-application no-source
+ (build-primref no-source (car x))
+ (map regen (cdr x)))))))
+
+ (lambda (e r w s mod)
+ (let ((e (source-wrap e w s mod)))
+ (syntax-case e ()
+ ((_ x)
+ (call-with-values
+ (lambda () (gen-syntax e #'x r '() ellipsis? mod))
+ (lambda (e maps) (regen e))))
+ (_ (syntax-violation 'syntax "bad `syntax' form" e)))))))
+
+ (global-extend 'core 'lambda
+ (lambda (e r w s mod)
+ (syntax-case e ()
+ ((_ args e1 e2 ...)
+ (call-with-values (lambda () (lambda-formals #'args))
+ (lambda (req opt rest kw)
+ (let lp ((body #'(e1 e2 ...)) (meta '()))
+ (syntax-case body ()
+ ((docstring e1 e2 ...) (string? (syntax->datum #'docstring))
+ (lp #'(e1 e2 ...)
+ (append meta
+ `((documentation
+ . ,(syntax->datum #'docstring))))))
+ ((#((k . v) ...) e1 e2 ...)
+ (lp #'(e1 e2 ...)
+ (append meta (syntax->datum #'((k . v) ...)))))
+ (_ (chi-simple-lambda e r w s mod req rest meta body)))))))
+ (_ (syntax-violation 'lambda "bad lambda" e)))))
+
+ (global-extend 'core 'lambda*
+ (lambda (e r w s mod)
+ (syntax-case e ()
+ ((_ args e1 e2 ...)
+ (call-with-values
+ (lambda ()
+ (chi-lambda-case e r w s mod
+ lambda*-formals #'((args e1 e2 ...))))
+ (lambda (meta lcase)
+ (build-case-lambda s meta lcase))))
+ (_ (syntax-violation 'lambda "bad lambda*" e)))))
+
+ (global-extend 'core 'case-lambda
+ (lambda (e r w s mod)
+ (syntax-case e ()
+ ((_ (args e1 e2 ...) (args* e1* e2* ...) ...)
+ (call-with-values
+ (lambda ()
+ (chi-lambda-case e r w s mod
+ lambda-formals
+ #'((args e1 e2 ...) (args* e1* e2* ...) ...)))
+ (lambda (meta lcase)
+ (build-case-lambda s meta lcase))))
+ (_ (syntax-violation 'case-lambda "bad case-lambda" e)))))
+
+ (global-extend 'core 'case-lambda*
+ (lambda (e r w s mod)
+ (syntax-case e ()
+ ((_ (args e1 e2 ...) (args* e1* e2* ...) ...)
+ (call-with-values
+ (lambda ()
+ (chi-lambda-case e r w s mod
+ lambda*-formals
+ #'((args e1 e2 ...) (args* e1* e2* ...) ...)))
+ (lambda (meta lcase)
+ (build-case-lambda s meta lcase))))
+ (_ (syntax-violation 'case-lambda "bad case-lambda*" e)))))
+
+ (global-extend 'core 'let
+ (let ()
+ (define (chi-let e r w s mod constructor ids vals exps)
+ (if (not (valid-bound-ids? ids))
+ (syntax-violation 'let "duplicate bound variable" e)
+ (let ((labels (gen-labels ids))
+ (new-vars (map gen-var ids)))
+ (let ((nw (make-binding-wrap ids labels w))
+ (nr (extend-var-env labels new-vars r)))
+ (constructor s
+ (map syntax->datum ids)
+ new-vars
+ (map (lambda (x) (chi x r w mod)) vals)
+ (chi-body exps (source-wrap e nw s mod)
+ nr nw mod))))))
+ (lambda (e r w s mod)
+ (syntax-case e ()
+ ((_ ((id val) ...) e1 e2 ...)
+ (and-map id? #'(id ...))
+ (chi-let e r w s mod
+ build-let
+ #'(id ...)
+ #'(val ...)
+ #'(e1 e2 ...)))
+ ((_ f ((id val) ...) e1 e2 ...)
+ (and (id? #'f) (and-map id? #'(id ...)))
+ (chi-let e r w s mod
+ build-named-let
+ #'(f id ...)
+ #'(val ...)
+ #'(e1 e2 ...)))
+ (_ (syntax-violation 'let "bad let" (source-wrap e w s mod)))))))
+
+
+ (global-extend 'core 'letrec
+ (lambda (e r w s mod)
+ (syntax-case e ()
+ ((_ ((id val) ...) e1 e2 ...)
+ (and-map id? #'(id ...))
+ (let ((ids #'(id ...)))
+ (if (not (valid-bound-ids? ids))
+ (syntax-violation 'letrec "duplicate bound variable" e)
+ (let ((labels (gen-labels ids))
+ (new-vars (map gen-var ids)))
+ (let ((w (make-binding-wrap ids labels w))
+ (r (extend-var-env labels new-vars r)))
+ (build-letrec s #f
+ (map syntax->datum ids)
+ new-vars
+ (map (lambda (x) (chi x r w mod)) #'(val ...))
+ (chi-body #'(e1 e2 ...)
+ (source-wrap e w s mod) r w mod)))))))
+ (_ (syntax-violation 'letrec "bad letrec" (source-wrap e w s mod))))))
+
+
+ (global-extend 'core 'letrec*
+ (lambda (e r w s mod)
+ (syntax-case e ()
+ ((_ ((id val) ...) e1 e2 ...)
+ (and-map id? #'(id ...))
+ (let ((ids #'(id ...)))
+ (if (not (valid-bound-ids? ids))
+ (syntax-violation 'letrec* "duplicate bound variable" e)
+ (let ((labels (gen-labels ids))
+ (new-vars (map gen-var ids)))
+ (let ((w (make-binding-wrap ids labels w))
+ (r (extend-var-env labels new-vars r)))
+ (build-letrec s #t
+ (map syntax->datum ids)
+ new-vars
+ (map (lambda (x) (chi x r w mod)) #'(val ...))
+ (chi-body #'(e1 e2 ...)
+ (source-wrap e w s mod) r w mod)))))))
+ (_ (syntax-violation 'letrec* "bad letrec*" (source-wrap e w s mod))))))
+
+
+ (global-extend 'core 'set!
+ (lambda (e r w s mod)
+ (syntax-case e ()
+ ((_ id val)
+ (id? #'id)
+ (let ((n (id-var-name #'id w))
+ ;; Lookup id in its module
+ (id-mod (if (syntax-object? #'id)
+ (syntax-object-module #'id)
+ mod)))
+ (let ((b (lookup n r id-mod)))
+ (case (binding-type b)
+ ((lexical)
+ (build-lexical-assignment s
+ (syntax->datum #'id)
+ (binding-value b)
+ (chi #'val r w mod)))
+ ((global)
+ (build-global-assignment s n (chi #'val r w mod) id-mod))
+ ((macro)
+ (let ((p (binding-value b)))
+ (if (procedure-property p 'variable-transformer)
+ ;; As syntax-type does, call chi-macro with
+ ;; the mod of the expression. Hmm.
+ (chi (chi-macro p e r w s #f mod) r empty-wrap mod)
+ (syntax-violation 'set! "not a variable transformer"
+ (wrap e w mod)
+ (wrap #'id w id-mod)))))
+ ((displaced-lexical)
+ (syntax-violation 'set! "identifier out of context"
+ (wrap #'id w mod)))
+ (else (syntax-violation 'set! "bad set!"
+ (source-wrap e w s mod)))))))
+ ((_ (head tail ...) val)
+ (call-with-values
+ (lambda () (syntax-type #'head r empty-wrap no-source #f mod #t))
+ (lambda (type value ee ww ss modmod)
+ (case type
+ ((module-ref)
+ (let ((val (chi #'val r w mod)))
+ (call-with-values (lambda () (value #'(head tail ...) r w))
+ (lambda (e r w s* mod)
+ (syntax-case e ()
+ (e (id? #'e)
+ (build-global-assignment s (syntax->datum #'e)
+ val mod)))))))
+ (else
+ (build-application s
+ (chi #'(setter head) r w mod)
+ (map (lambda (e) (chi e r w mod))
+ #'(tail ... val))))))))
+ (_ (syntax-violation 'set! "bad set!" (source-wrap e w s mod))))))
+
+ (global-extend 'module-ref '@
+ (lambda (e r w)
+ (syntax-case e ()
+ ((_ (mod ...) id)
+ (and (and-map id? #'(mod ...)) (id? #'id))
+ (values (syntax->datum #'id) r w #f
+ (syntax->datum
+ #'(public mod ...)))))))
+
+ (global-extend 'module-ref '@@
+ (lambda (e r w)
+ (define remodulate
+ (lambda (x mod)
+ (cond ((pair? x)
+ (cons (remodulate (car x) mod)
+ (remodulate (cdr x) mod)))
+ ((syntax-object? x)
+ (make-syntax-object
+ (remodulate (syntax-object-expression x) mod)
+ (syntax-object-wrap x)
+ ;; hither the remodulation
+ mod))
+ ((vector? x)
+ (let* ((n (vector-length x)) (v (make-vector n)))
+ (do ((i 0 (fx+ i 1)))
+ ((fx= i n) v)
+ (vector-set! v i (remodulate (vector-ref x i) mod)))))
+ (else x))))
+ (syntax-case e ()
+ ((_ (mod ...) exp)
+ (and-map id? #'(mod ...))
+ (let ((mod (syntax->datum #'(private mod ...))))
+ (values (remodulate #'exp mod)
+ r w (source-annotation #'exp)
+ mod))))))
+
+ (global-extend 'core 'if
+ (lambda (e r w s mod)
+ (syntax-case e ()
+ ((_ test then)
+ (build-conditional
+ s
+ (chi #'test r w mod)
+ (chi #'then r w mod)
+ (build-void no-source)))
+ ((_ test then else)
+ (build-conditional
+ s
+ (chi #'test r w mod)
+ (chi #'then r w mod)
+ (chi #'else r w mod))))))
+
+ (global-extend 'core 'with-fluids
+ (lambda (e r w s mod)
+ (syntax-case e ()
+ ((_ ((fluid val) ...) b b* ...)
+ (build-dynlet
+ s
+ (map (lambda (x) (chi x r w mod)) #'(fluid ...))
+ (map (lambda (x) (chi x r w mod)) #'(val ...))
+ (chi-body #'(b b* ...)
+ (source-wrap e w s mod) r w mod))))))
+
+ (global-extend 'begin 'begin '())
+
+ (global-extend 'define 'define '())
+
+ (global-extend 'define-syntax 'define-syntax '())
+
+ (global-extend 'eval-when 'eval-when '())
+
+ (global-extend 'core 'syntax-case
+ (let ()
+ (define convert-pattern
+ ;; accepts pattern & keys
+ ;; returns $sc-dispatch pattern & ids
+ (lambda (pattern keys)
+ (define cvt*
+ (lambda (p* n ids)
+ (if (null? p*)
+ (values '() ids)
+ (call-with-values
+ (lambda () (cvt* (cdr p*) n ids))
+ (lambda (y ids)
+ (call-with-values
+ (lambda () (cvt (car p*) n ids))
+ (lambda (x ids)
+ (values (cons x y) ids))))))))
+ (define cvt
+ (lambda (p n ids)
+ (if (id? p)
+ (cond
+ ((bound-id-member? p keys)
+ (values (vector 'free-id p) ids))
+ ((free-id=? p #'_)
+ (values '_ ids))
+ (else
+ (values 'any (cons (cons p n) ids))))
+ (syntax-case p ()
+ ((x dots)
+ (ellipsis? (syntax dots))
+ (call-with-values
+ (lambda () (cvt (syntax x) (fx+ n 1) ids))
+ (lambda (p ids)
+ (values (if (eq? p 'any) 'each-any (vector 'each p))
+ ids))))
+ ((x dots ys ...)
+ (ellipsis? (syntax dots))
+ (call-with-values
+ (lambda () (cvt* (syntax (ys ...)) n ids))
+ (lambda (ys ids)
+ (call-with-values
+ (lambda () (cvt (syntax x) (+ n 1) ids))
+ (lambda (x ids)
+ (values `#(each+ ,x ,(reverse ys) ()) ids))))))
+ ((x . y)
+ (call-with-values
+ (lambda () (cvt (syntax y) n ids))
+ (lambda (y ids)
+ (call-with-values
+ (lambda () (cvt (syntax x) n ids))
+ (lambda (x ids)
+ (values (cons x y) ids))))))
+ (() (values '() ids))
+ (#(x ...)
+ (call-with-values
+ (lambda () (cvt (syntax (x ...)) n ids))
+ (lambda (p ids) (values (vector 'vector p) ids))))
+ (x (values (vector 'atom (strip p empty-wrap)) ids))))))
+ (cvt pattern 0 '())))
+
+ (define build-dispatch-call
+ (lambda (pvars exp y r mod)
+ (let ((ids (map car pvars)) (levels (map cdr pvars)))
+ (let ((labels (gen-labels ids)) (new-vars (map gen-var ids)))
+ (build-application no-source
+ (build-primref no-source 'apply)
+ (list (build-simple-lambda no-source (map syntax->datum ids) #f new-vars '()
+ (chi exp
+ (extend-env
+ labels
+ (map (lambda (var level)
+ (make-binding 'syntax `(,var . ,level)))
+ new-vars
+ (map cdr pvars))
+ r)
+ (make-binding-wrap ids labels empty-wrap)
+ mod))
+ y))))))
+
+ (define gen-clause
+ (lambda (x keys clauses r pat fender exp mod)
+ (call-with-values
+ (lambda () (convert-pattern pat keys))
+ (lambda (p pvars)
+ (cond
+ ((not (distinct-bound-ids? (map car pvars)))
+ (syntax-violation 'syntax-case "duplicate pattern variable" pat))
+ ((not (and-map (lambda (x) (not (ellipsis? (car x)))) pvars))
+ (syntax-violation 'syntax-case "misplaced ellipsis" pat))
+ (else
+ (let ((y (gen-var 'tmp)))
+ ;; fat finger binding and references to temp variable y
+ (build-application no-source
+ (build-simple-lambda no-source (list 'tmp) #f (list y) '()
+ (let ((y (build-lexical-reference 'value no-source
+ 'tmp y)))
+ (build-conditional no-source
+ (syntax-case fender ()
+ (#t y)
+ (_ (build-conditional no-source
+ y
+ (build-dispatch-call pvars fender y r mod)
+ (build-data no-source #f))))
+ (build-dispatch-call pvars exp y r mod)
+ (gen-syntax-case x keys clauses r mod))))
+ (list (if (eq? p 'any)
+ (build-application no-source
+ (build-primref no-source 'list)
+ (list x))
+ (build-application no-source
+ (build-primref no-source '$sc-dispatch)
+ (list x (build-data no-source p)))))))))))))
+
+ (define gen-syntax-case
+ (lambda (x keys clauses r mod)
+ (if (null? clauses)
+ (build-application no-source
+ (build-primref no-source 'syntax-violation)
+ (list (build-data no-source #f)
+ (build-data no-source
+ "source expression failed to match any pattern")
+ x))
+ (syntax-case (car clauses) ()
+ ((pat exp)
+ (if (and (id? #'pat)
+ (and-map (lambda (x) (not (free-id=? #'pat x)))
+ (cons #'(... ...) keys)))
+ (if (free-id=? #'pad #'_)
+ (chi #'exp r empty-wrap mod)
+ (let ((labels (list (gen-label)))
+ (var (gen-var #'pat)))
+ (build-application no-source
+ (build-simple-lambda
+ no-source (list (syntax->datum #'pat)) #f (list var)
+ '()
+ (chi #'exp
+ (extend-env labels
+ (list (make-binding 'syntax `(,var . 0)))
+ r)
+ (make-binding-wrap #'(pat)
+ labels empty-wrap)
+ mod))
+ (list x))))
+ (gen-clause x keys (cdr clauses) r
+ #'pat #t #'exp mod)))
+ ((pat fender exp)
+ (gen-clause x keys (cdr clauses) r
+ #'pat #'fender #'exp mod))
+ (_ (syntax-violation 'syntax-case "invalid clause"
+ (car clauses)))))))
+
+ (lambda (e r w s mod)
+ (let ((e (source-wrap e w s mod)))
+ (syntax-case e ()
+ ((_ val (key ...) m ...)
+ (if (and-map (lambda (x) (and (id? x) (not (ellipsis? x))))
+ #'(key ...))
+ (let ((x (gen-var 'tmp)))
+ ;; fat finger binding and references to temp variable x
+ (build-application s
+ (build-simple-lambda no-source (list 'tmp) #f (list x) '()
+ (gen-syntax-case (build-lexical-reference 'value no-source
+ 'tmp x)
+ #'(key ...) #'(m ...)
+ r
+ mod))
+ (list (chi #'val r empty-wrap mod))))
+ (syntax-violation 'syntax-case "invalid literals list" e))))))))
+
+ ;; The portable macroexpand seeds chi-top's mode m with 'e (for
+ ;; evaluating) and esew (which stands for "eval syntax expanders
+ ;; when") with '(eval). In Chez Scheme, m is set to 'c instead of e
+ ;; if we are compiling a file, and esew is set to
+ ;; (eval-syntactic-expanders-when), which defaults to the list
+ ;; '(compile load eval). This means that, by default, top-level
+ ;; syntactic definitions are evaluated immediately after they are
+ ;; expanded, and the expanded definitions are also residualized into
+ ;; the object file if we are compiling a file.
+ (set! macroexpand
+ (lambda* (x #:optional (m 'e) (esew '(eval)))
+ (chi-top x null-env top-wrap m esew
+ (cons 'hygiene (module-name (current-module))))))
+
+ (set! identifier?
+ (lambda (x)
+ (nonsymbol-id? x)))
+
+ (set! datum->syntax
+ (lambda (id datum)
+ (make-syntax-object datum (syntax-object-wrap id)
+ (syntax-object-module id))))
+
+ (set! syntax->datum
+ ;; accepts any object, since syntax objects may consist partially
+ ;; or entirely of unwrapped, nonsymbolic data
+ (lambda (x)
+ (strip x empty-wrap)))
+
+ (set! syntax-source
+ (lambda (x) (source-annotation x)))
+
+ (set! generate-temporaries
+ (lambda (ls)
+ (arg-check list? ls 'generate-temporaries)
+ (map (lambda (x) (wrap (gensym-hook) top-wrap #f)) ls)))
+
+ (set! free-identifier=?
+ (lambda (x y)
+ (arg-check nonsymbol-id? x 'free-identifier=?)
+ (arg-check nonsymbol-id? y 'free-identifier=?)
+ (free-id=? x y)))
+
+ (set! bound-identifier=?
+ (lambda (x y)
+ (arg-check nonsymbol-id? x 'bound-identifier=?)
+ (arg-check nonsymbol-id? y 'bound-identifier=?)
+ (bound-id=? x y)))
+
+ (set! syntax-violation
+ (lambda (who message form . subform)
+ (arg-check (lambda (x) (or (not x) (string? x) (symbol? x)))
+ who 'syntax-violation)
+ (arg-check string? message 'syntax-violation)
+ (scm-error 'syntax-error 'macroexpand
+ (string-append
+ (if who "~a: " "")
+ "~a "
+ (if (null? subform) "in ~a" "in subform `~s' of `~s'"))
+ (let ((tail (cons message
+ (map (lambda (x) (strip x empty-wrap))
+ (append subform (list form))))))
+ (if who (cons who tail) tail))
+ #f)))
+
+ ;; $sc-dispatch expects an expression and a pattern. If the expression
+ ;; matches the pattern a list of the matching expressions for each
+ ;; "any" is returned. Otherwise, #f is returned. (This use of #f will
+ ;; not work on r4rs implementations that violate the ieee requirement
+ ;; that #f and () be distinct.)
+
+ ;; The expression is matched with the pattern as follows:
+
+ ;; pattern: matches:
+ ;; () empty list
+ ;; any anything
+ ;; (<pattern>1 . <pattern>2) (<pattern>1 . <pattern>2)
+ ;; each-any (any*)
+ ;; #(free-id <key>) <key> with free-identifier=?
+ ;; #(each <pattern>) (<pattern>*)
+ ;; #(each+ p1 (p2_1 ... p2_n) p3) (p1* (p2_n ... p2_1) . p3)
+ ;; #(vector <pattern>) (list->vector <pattern>)
+ ;; #(atom <object>) <object> with "equal?"
+
+ ;; Vector cops out to pair under assumption that vectors are rare. If
+ ;; not, should convert to:
+ ;; #(vector <pattern>*) #(<pattern>*)
+
+ (let ()
+
+ (define match-each
+ (lambda (e p w mod)
+ (cond
+ ((pair? e)
+ (let ((first (match (car e) p w '() mod)))
+ (and first
+ (let ((rest (match-each (cdr e) p w mod)))
+ (and rest (cons first rest))))))
+ ((null? e) '())
+ ((syntax-object? e)
+ (match-each (syntax-object-expression e)
+ p
+ (join-wraps w (syntax-object-wrap e))
+ (syntax-object-module e)))
+ (else #f))))
+
+ (define match-each+
+ (lambda (e x-pat y-pat z-pat w r mod)
+ (let f ((e e) (w w))
+ (cond
+ ((pair? e)
+ (call-with-values (lambda () (f (cdr e) w))
+ (lambda (xr* y-pat r)
+ (if r
+ (if (null? y-pat)
+ (let ((xr (match (car e) x-pat w '() mod)))
+ (if xr
+ (values (cons xr xr*) y-pat r)
+ (values #f #f #f)))
+ (values
+ '()
+ (cdr y-pat)
+ (match (car e) (car y-pat) w r mod)))
+ (values #f #f #f)))))
+ ((syntax-object? e)
+ (f (syntax-object-expression e) (join-wraps w e)))
+ (else
+ (values '() y-pat (match e z-pat w r mod)))))))
+
+ (define match-each-any
+ (lambda (e w mod)
+ (cond
+ ((pair? e)
+ (let ((l (match-each-any (cdr e) w mod)))
+ (and l (cons (wrap (car e) w mod) l))))
+ ((null? e) '())
+ ((syntax-object? e)
+ (match-each-any (syntax-object-expression e)
+ (join-wraps w (syntax-object-wrap e))
+ mod))
+ (else #f))))
+
+ (define match-empty
+ (lambda (p r)
+ (cond
+ ((null? p) r)
+ ((eq? p '_) r)
+ ((eq? p 'any) (cons '() r))
+ ((pair? p) (match-empty (car p) (match-empty (cdr p) r)))
+ ((eq? p 'each-any) (cons '() r))
+ (else
+ (case (vector-ref p 0)
+ ((each) (match-empty (vector-ref p 1) r))
+ ((each+) (match-empty (vector-ref p 1)
+ (match-empty
+ (reverse (vector-ref p 2))
+ (match-empty (vector-ref p 3) r))))
+ ((free-id atom) r)
+ ((vector) (match-empty (vector-ref p 1) r)))))))
+
+ (define combine
+ (lambda (r* r)
+ (if (null? (car r*))
+ r
+ (cons (map car r*) (combine (map cdr r*) r)))))
+
+ (define match*
+ (lambda (e p w r mod)
+ (cond
+ ((null? p) (and (null? e) r))
+ ((pair? p)
+ (and (pair? e) (match (car e) (car p) w
+ (match (cdr e) (cdr p) w r mod)
+ mod)))
+ ((eq? p 'each-any)
+ (let ((l (match-each-any e w mod))) (and l (cons l r))))
+ (else
+ (case (vector-ref p 0)
+ ((each)
+ (if (null? e)
+ (match-empty (vector-ref p 1) r)
+ (let ((l (match-each e (vector-ref p 1) w mod)))
+ (and l
+ (let collect ((l l))
+ (if (null? (car l))
+ r
+ (cons (map car l) (collect (map cdr l)))))))))
+ ((each+)
+ (call-with-values
+ (lambda ()
+ (match-each+ e (vector-ref p 1) (vector-ref p 2) (vector-ref p 3) w r mod))
+ (lambda (xr* y-pat r)
+ (and r
+ (null? y-pat)
+ (if (null? xr*)
+ (match-empty (vector-ref p 1) r)
+ (combine xr* r))))))
+ ((free-id) (and (id? e) (free-id=? (wrap e w mod) (vector-ref p 1)) r))
+ ((atom) (and (equal? (vector-ref p 1) (strip e w)) r))
+ ((vector)
+ (and (vector? e)
+ (match (vector->list e) (vector-ref p 1) w r mod))))))))
+
+ (define match
+ (lambda (e p w r mod)
+ (cond
+ ((not r) #f)
+ ((eq? p '_) r)
+ ((eq? p 'any) (cons (wrap e w mod) r))
+ ((syntax-object? e)
+ (match*
+ (syntax-object-expression e)
+ p
+ (join-wraps w (syntax-object-wrap e))
+ r
+ (syntax-object-module e)))
+ (else (match* e p w r mod)))))
+
+ (set! $sc-dispatch
+ (lambda (e p)
+ (cond
+ ((eq? p 'any) (list e))
+ ((eq? p '_) '())
+ ((syntax-object? e)
+ (match* (syntax-object-expression e)
+ p (syntax-object-wrap e) '() (syntax-object-module e)))
+ (else (match* e p empty-wrap '() #f))))))))
+
+
+(define-syntax with-syntax
+ (lambda (x)
+ (syntax-case x ()
+ ((_ () e1 e2 ...)
+ #'(begin e1 e2 ...))
+ ((_ ((out in)) e1 e2 ...)
+ #'(syntax-case in () (out (begin e1 e2 ...))))
+ ((_ ((out in) ...) e1 e2 ...)
+ #'(syntax-case (list in ...) ()
+ ((out ...) (begin e1 e2 ...)))))))
+
+(define-syntax syntax-rules
+ (lambda (x)
+ (syntax-case x ()
+ ((_ (k ...) ((keyword . pattern) template) ...)
+ #'(lambda (x)
+ ;; embed patterns as procedure metadata
+ #((macro-type . syntax-rules)
+ (patterns pattern ...))
+ (syntax-case x (k ...)
+ ((dummy . pattern) #'template)
+ ...))))))
+
+(define-syntax let*
+ (lambda (x)
+ (syntax-case x ()
+ ((let* ((x v) ...) e1 e2 ...)
+ (and-map identifier? #'(x ...))
+ (let f ((bindings #'((x v) ...)))
+ (if (null? bindings)
+ #'(let () e1 e2 ...)
+ (with-syntax ((body (f (cdr bindings)))
+ (binding (car bindings)))
+ #'(let (binding) body))))))))
+
+(define-syntax do
+ (lambda (orig-x)
+ (syntax-case orig-x ()
+ ((_ ((var init . step) ...) (e0 e1 ...) c ...)
+ (with-syntax (((step ...)
+ (map (lambda (v s)
+ (syntax-case s ()
+ (() v)
+ ((e) #'e)
+ (_ (syntax-violation
+ 'do "bad step expression"
+ orig-x s))))
+ #'(var ...)
+ #'(step ...))))
+ (syntax-case #'(e1 ...) ()
+ (() #'(let doloop ((var init) ...)
+ (if (not e0)
+ (begin c ... (doloop step ...)))))
+ ((e1 e2 ...)
+ #'(let doloop ((var init) ...)
+ (if e0
+ (begin e1 e2 ...)
+ (begin c ... (doloop step ...)))))))))))
+
+(define-syntax quasiquote
+ (letrec
+ ((quasicons
+ (lambda (x y)
+ (with-syntax ((x x) (y y))
+ (syntax-case #'y (quote list)
+ ((quote dy)
+ (syntax-case #'x (quote)
+ ((quote dx) #'(quote (dx . dy)))
+ (_ (if (null? #'dy)
+ #'(list x)
+ #'(cons x y)))))
+ ((list . stuff) #'(list x . stuff))
+ (else #'(cons x y))))))
+ (quasiappend
+ (lambda (x y)
+ (with-syntax ((x x) (y y))
+ (syntax-case #'y (quote)
+ ((quote ()) #'x)
+ (_ #'(append x y))))))
+ (quasivector
+ (lambda (x)
+ (with-syntax ((x x))
+ (syntax-case #'x (quote list)
+ ((quote (x ...)) #'(quote #(x ...)))
+ ((list x ...) #'(vector x ...))
+ (_ #'(list->vector x))))))
+ (quasi
+ (lambda (p lev)
+ (syntax-case p (unquote unquote-splicing quasiquote)
+ ((unquote p)
+ (if (= lev 0)
+ #'p
+ (quasicons #'(quote unquote)
+ (quasi #'(p) (- lev 1)))))
+ ((unquote . args)
+ (= lev 0)
+ (syntax-violation 'unquote
+ "unquote takes exactly one argument"
+ p #'(unquote . args)))
+ (((unquote-splicing p) . q)
+ (if (= lev 0)
+ (quasiappend #'p (quasi #'q lev))
+ (quasicons (quasicons #'(quote unquote-splicing)
+ (quasi #'(p) (- lev 1)))
+ (quasi #'q lev))))
+ (((unquote-splicing . args) . q)
+ (= lev 0)
+ (syntax-violation 'unquote-splicing
+ "unquote-splicing takes exactly one argument"
+ p #'(unquote-splicing . args)))
+ ((quasiquote p)
+ (quasicons #'(quote quasiquote)
+ (quasi #'(p) (+ lev 1))))
+ ((p . q)
+ (quasicons (quasi #'p lev) (quasi #'q lev)))
+ (#(x ...) (quasivector (quasi #'(x ...) lev)))
+ (p #'(quote p))))))
+ (lambda (x)
+ (syntax-case x ()
+ ((_ e) (quasi #'e 0))))))
+
+(define-syntax include
+ (lambda (x)
+ (define read-file
+ (lambda (fn k)
+ (let ((p (open-input-file fn)))
+ (let f ((x (read p))
+ (result '()))
+ (if (eof-object? x)
+ (begin
+ (close-input-port p)
+ (reverse result))
+ (f (read p)
+ (cons (datum->syntax k x) result)))))))
+ (syntax-case x ()
+ ((k filename)
+ (let ((fn (syntax->datum #'filename)))
+ (with-syntax (((exp ...) (read-file fn #'filename)))
+ #'(begin exp ...)))))))
+
+(define-syntax include-from-path
+ (lambda (x)
+ (syntax-case x ()
+ ((k filename)
+ (let ((fn (syntax->datum #'filename)))
+ (with-syntax ((fn (datum->syntax
+ #'filename
+ (or (%search-load-path fn)
+ (syntax-violation 'include-from-path
+ "file not found in path"
+ x #'filename)))))
+ #'(include fn)))))))
+
+(define-syntax unquote
+ (lambda (x)
+ (syntax-case x ()
+ ((_ e)
+ (syntax-violation 'unquote
+ "expression not valid outside of quasiquote"
+ x)))))
+
+(define-syntax unquote-splicing
+ (lambda (x)
+ (syntax-case x ()
+ ((_ e)
+ (syntax-violation 'unquote-splicing
+ "expression not valid outside of quasiquote"
+ x)))))
+
+(define-syntax case
+ (lambda (x)
+ (syntax-case x ()
+ ((_ e m1 m2 ...)
+ (with-syntax
+ ((body (let f ((clause #'m1) (clauses #'(m2 ...)))
+ (if (null? clauses)
+ (syntax-case clause (else)
+ ((else e1 e2 ...) #'(begin e1 e2 ...))
+ (((k ...) e1 e2 ...)
+ #'(if (memv t '(k ...)) (begin e1 e2 ...)))
+ (_ (syntax-violation 'case "bad clause" x clause)))
+ (with-syntax ((rest (f (car clauses) (cdr clauses))))
+ (syntax-case clause (else)
+ (((k ...) e1 e2 ...)
+ #'(if (memv t '(k ...))
+ (begin e1 e2 ...)
+ rest))
+ (_ (syntax-violation 'case "bad clause" x
+ clause))))))))
+ #'(let ((t e)) body))))))
+
+(define (make-variable-transformer proc)
+ (if (procedure? proc)
+ (let ((trans (lambda (x)
+ #((macro-type . variable-transformer))
+ (proc x))))
+ (set-procedure-property! trans 'variable-transformer #t)
+ trans)
+ (error "variable transformer not a procedure" proc)))
+
+(define-syntax identifier-syntax
+ (lambda (x)
+ (syntax-case x (set!)
+ ((_ e)
+ #'(lambda (x)
+ #((macro-type . identifier-syntax))
+ (syntax-case x ()
+ (id
+ (identifier? #'id)
+ #'e)
+ ((_ x (... ...))
+ #'(e x (... ...))))))
+ ((_ (id exp1) ((set! var val) exp2))
+ (and (identifier? #'id) (identifier? #'var))
+ #'(make-variable-transformer
+ (lambda (x)
+ #((macro-type . variable-transformer))
+ (syntax-case x (set!)
+ ((set! var val) #'exp2)
+ ((id x (... ...)) #'(exp1 x (... ...)))
+ (id (identifier? #'id) #'exp1))))))))
+
+(define-syntax define*
+ (lambda (x)
+ (syntax-case x ()
+ ((_ (id . args) b0 b1 ...)
+ #'(define id (lambda* args b0 b1 ...)))
+ ((_ id val) (identifier? #'x)
+ #'(define id val)))))
HCoop / bpt / guile.git / commitdiff