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
   5 ;;;; the Free Software Foundation; either version 2, or (at your option)
   6 ;;;; any later version.
   7 ;;;;
   8 ;;;; This program is distributed in the hope that it will be useful,
   9 ;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 ;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 ;;;; GNU General Public License for more details.
  12 ;;;;
  13 ;;;; You should have received a copy of the GNU General Public License
  14 ;;;; along with this software; see the file COPYING.  If not, write to
  15 ;;;; the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  16 ;;;; Boston, MA 02111-1307 USA
  17 ;;;;
  18 \f
  19
  20 (define-module (ice-9 syncase)
  21   :use-module (ice-9 debug))
  22
  23 \f
  24
  25 (define-public sc-macro
  26   (procedure->memoizing-macro
  27     (lambda (exp env)
  28       (sc-expand exp))))
  29
  30 ;;; Exported variables
  31
  32 (define-public sc-expand #f)
  33 (define-public sc-expand3 #f)
  34 (define-public install-global-transformer #f)
  35 (define-public syntax-dispatch #f)
  36 (define-public syntax-error #f)
  37
  38 (define-public bound-identifier=? #f)
  39 (define-public datum->syntax-object #f)
  40 (define-public define-syntax sc-macro)
  41 (define-public eval-when sc-macro)
  42 (define-public fluid-let-syntax sc-macro)
  43 (define-public free-identifier=? #f)
  44 (define-public generate-temporaries #f)
  45 (define-public identifier? #f)
  46 (define-public identifier-syntax sc-macro)
  47 (define-public let-syntax sc-macro)
  48 (define-public letrec-syntax sc-macro)
  49 (define-public syntax sc-macro)
  50 (define-public syntax-case sc-macro)
  51 (define-public syntax-object->datum #f)
  52 (define-public syntax-rules sc-macro)
  53 (define-public with-syntax sc-macro)
  54 (define-public include sc-macro)
  55
  56 (define primitive-syntax '(quote lambda letrec if set! begin define or
  57                               and let let* cond do quasiquote unquote
  58                               unquote-splicing case))
  59
  60 (for-each (lambda (symbol)
  61             (set-symbol-property! symbol 'primitive-syntax #t))
  62           primitive-syntax)
  63
  64 ;;; Hooks needed by the syntax-case macro package
  65
  66 (define-public (void) *unspecified*)
  67
  68 (define andmap
  69   (lambda (f first . rest)
  70     (or (null? first)
  71         (if (null? rest)
  72             (let andmap ((first first))
  73               (let ((x (car first)) (first (cdr first)))
  74                 (if (null? first)
  75                     (f x)
  76                     (and (f x) (andmap first)))))
  77             (let andmap ((first first) (rest rest))
  78               (let ((x (car first))
  79                     (xr (map car rest))
  80                     (first (cdr first))
  81                     (rest (map cdr rest)))
  82                 (if (null? first)
  83                     (apply f (cons x xr))
  84                     (and (apply f (cons x xr)) (andmap first rest)))))))))
  85
  86 (define (error who format-string why what)
  87   (start-stack 'syncase-stack
  88                (scm-error 'misc-error
  89                           who
  90                           "%s %S"
  91                           (list why what)
  92                           '())))
  93
  94 (define the-syncase-module (current-module))
  95
  96 (define (putprop symbol key binding)
  97   (let* ((m (current-module))
  98          (v (or (module-variable m symbol)
  99                 (module-make-local-var! m symbol))))
 100     (if (assq 'primitive-syntax (symbol-pref symbol))
 101         (if (eq? (current-module) the-syncase-module)
 102             (set-object-property! (module-variable the-root-module symbol)
 103                                   key
 104                                   binding))
 105         (variable-set! v sc-macro))
 106     (set-object-property! v key binding)))
 107
 108 (define (getprop symbol key)
 109   (let* ((m (current-module))
 110          (v (module-variable m symbol)))
 111     (and v (or (object-property v key)
 112                (let ((root-v (module-local-variable the-root-module symbol)))
 113                  (and (equal? root-v v)
 114                       (object-property root-v key)))))))
 115
 116 (define generated-symbols (make-weak-key-hash-table 1019))
 117
 118 ;;; Utilities
 119
 120 (define (psyncomp)
 121   (system "mv -f psyntax.pp psyntax.pp~")
 122   (let ((in (open-input-file "psyntax.ss"))
 123         (out (open-output-file "psyntax.pp")))
 124     (let loop ((x (read in)))
 125       (if (eof-object? x)
 126           (begin
 127             (close-port out)
 128             (close-port in))
 129           (begin
 130             (write (sc-expand3 x 'c '(compile load eval)) out)
 131             (newline out)
 132             (loop (read in)))))))
 133
 134 ;;; Load the preprocessed code
 135
 136 (let ((old-debug #f)
 137       (old-read #f))
 138   (dynamic-wind (lambda ()
 139                   (set! old-debug (debug-options))
 140                   (set! old-read (read-options)))
 141                 (lambda ()
 142                   (debug-disable 'debug 'procnames)
 143                   (read-disable 'positions)
 144                   (load-from-path "ice-9/psyntax.pp"))
 145                 (lambda ()
 146                   (debug-options old-debug)
 147                   (read-options old-read))))
 148
 149
 150 ;;; The following line is necessary only if we start making changes
 151 ;; (load-from-path "ice-9/psyntax.ss")
 152
 153 (define internal-eval (nested-ref the-scm-module '(app modules guile eval)))
 154
 155 (define-public (eval x)
 156   (internal-eval (if (and (pair? x)
 157                           (string=? (car x) "noexpand"))
 158                      (cadr x)
 159                      (sc-expand x))))
 160
 161 ;;; Hack to make syncase macros work in the slib module
 162 (let ((m (nested-ref the-root-module '(app modules ice-9 slib))))
 163   (if m
 164       (set-object-property! (module-local-variable m 'define)
 165                             '*sc-expander*
 166                             '(define))))
 167
 168 (define-public syncase sc-expand)