ice-9/syncase.scm

   1 ;;;;    Copyright (C) 1997 Free Software Foundation, Inc.
   2 ;;;;
   3 ;;;; This program is free software; you can redistribute it and/or modify
   4 ;;;; it under the terms of the GNU General Public License as published by
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   6 ;;;; any later version.
   7 ;;;;
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  10 ;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 ;;;; GNU General Public License for more details.
  12 ;;;;
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  14 ;;;; along with this software; see the file COPYING.  If not, write to
  15 ;;;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  16 ;;;;
  17 \f
  18
  19 (define-module (ice-9 syncase)
  20   :use-module (ice-9 debug))
  21
  22 \f
  23
  24 (define-public sc-macro
  25   (procedure->memoizing-macro
  26     (lambda (exp env)
  27       (sc-expand exp))))
  28
  29 ;;; Exported variables
  30
  31 (define-public sc-expand #f)
  32 (define-public sc-expand3 #f)
  33 (define-public install-global-transformer #f)
  34 (define-public syntax-dispatch #f)
  35 (define-public syntax-error #f)
  36
  37 (define-public bound-identifier=? #f)
  38 (define-public datum->syntax-object #f)
  39 (define-public define-syntax sc-macro)
  40 (define-public eval-when sc-macro)
  41 (define-public fluid-let-syntax sc-macro)
  42 (define-public free-identifier=? #f)
  43 (define-public generate-temporaries #f)
  44 (define-public identifier? #f)
  45 (define-public identifier-syntax sc-macro)
  46 (define-public let-syntax sc-macro)
  47 (define-public letrec-syntax sc-macro)
  48 (define-public syntax sc-macro)
  49 (define-public syntax-case sc-macro)
  50 (define-public syntax-object->datum #f)
  51 (define-public syntax-rules sc-macro)
  52 (define-public with-syntax sc-macro)
  53 (define-public include sc-macro)
  54
  55 (define primitive-syntax '(quote lambda letrec if set! begin define or
  56                               and let let* cond do quasiquote unquote
  57                               unquote-splicing case))
  58
  59 (for-each (lambda (symbol)
  60             (set-symbol-property! symbol 'primitive-syntax #t))
  61           primitive-syntax)
  62
  63 ;;; Hooks needed by the syntax-case macro package
  64
  65 (define-public (void) *unspecified*)
  66
  67 (define andmap
  68   (lambda (f first . rest)
  69     (or (null? first)
  70         (if (null? rest)
  71             (let andmap ((first first))
  72               (let ((x (car first)) (first (cdr first)))
  73                 (if (null? first)
  74                     (f x)
  75                     (and (f x) (andmap first)))))
  76             (let andmap ((first first) (rest rest))
  77               (let ((x (car first))
  78                     (xr (map car rest))
  79                     (first (cdr first))
  80                     (rest (map cdr rest)))
  81                 (if (null? first)
  82                     (apply f (cons x xr))
  83                     (and (apply f (cons x xr)) (andmap first rest)))))))))
  84
  85 (define (error who format-string why what)
  86   (start-stack 'syncase-stack
  87                (scm-error 'misc-error
  88                           who
  89                           "%s %S"
  90                           (list why what)
  91                           '())))
  92
  93 (define the-syncase-module (current-module))
  94
  95 (define (putprop symbol key binding)
  96   (let* ((m (current-module))
  97          (v (or (module-variable m symbol)
  98                 (module-make-local-var! m symbol))))
  99     (if (assq 'primitive-syntax (symbol-pref symbol))
 100         (if (eq? (current-module) the-syncase-module)
 101             (set-object-property! (module-variable the-root-module symbol)
 102                                   key
 103                                   binding))
 104         (variable-set! v sc-macro))
 105     (set-object-property! v key binding)))
 106
 107 (define (getprop symbol key)
 108   (let* ((m (current-module))
 109          (v (module-variable m symbol)))
 110     (and v (or (object-property v key)
 111                (let ((root-v (module-local-variable the-root-module symbol)))
 112                  (and (equal? root-v v)
 113                       (object-property root-v key)))))))
 114
 115 (define generated-symbols (make-weak-key-hash-table 1019))
 116
 117 ;;; Compatibility
 118
 119 (define values:*values-rtd*
 120   (make-record-type "values"
 121                     '(values)))
 122
 123 (define values
 124   (let ((make-values (record-constructor values:*values-rtd*)))
 125     (lambda x
 126       (if (and (not (null? x))
 127                (null? (cdr x)))
 128           (car x)
 129           (make-values x)))))
 130
 131 (define call-with-values
 132   (let ((access-values (record-accessor values:*values-rtd* 'values))
 133         (values-predicate? (record-predicate values:*values-rtd*)))
 134     (lambda (producer consumer)
 135       (let ((result (producer)))
 136         (if (values-predicate? result)
 137             (apply consumer (access-values result))
 138             (consumer result))))))
 139
 140 ;;; Utilities
 141
 142 (define (psyncomp)
 143   (system "mv -f psyntax.pp psyntax.pp~")
 144   (let ((in (open-input-file "psyntax.ss"))
 145         (out (open-output-file "psyntax.pp")))
 146     (let loop ((x (read in)))
 147       (if (eof-object? x)
 148           (begin
 149             (close-port out)
 150             (close-port in))
 151           (begin
 152             (write (sc-expand3 x 'c '(compile load eval)) out)
 153             (newline out)
 154             (loop (read in)))))))
 155
 156 ;;; Load the preprocessed code
 157
 158 (let ((old-debug #f)
 159       (old-read #f))
 160   (dynamic-wind (lambda ()
 161                   (set! old-debug (debug-options))
 162                   (set! old-read (read-options)))
 163                 (lambda ()
 164                   (debug-disable 'debug 'procnames)
 165                   (read-disable 'positions)
 166                   (load-from-path "ice-9/psyntax.pp"))
 167                 (lambda ()
 168                   (debug-options old-debug)
 169                   (read-options old-read))))
 170
 171
 172 ;;; The following line is necessary only if we start making changes
 173 ;; (load-from-path "ice-9/psyntax.ss")
 174
 175 (define internal-eval (nested-ref the-scm-module '(app modules guile eval)))
 176
 177 (define-public (eval x)
 178   (internal-eval (if (and (pair? x)
 179                           (string=? (car x) "noexpand"))
 180                      (cadr x)
 181                      (sc-expand x))))
 182
 183 ;;; Hack to make syncase macros work in the slib module
 184 (let ((m (nested-ref the-root-module '(app modules ice-9 slib))))
 185   (if m
 186       (set-object-property! (module-local-variable m 'define)
 187                             '*sc-expander*
 188                             '(define))))
 189
 190 (define-public syncase sc-expand)