Hi,
The patch below adds a `#:reader' keyword to `define-module' that allows
modules to specify the reader that should be used to interpret them:
(define-module (the-module)
#:reader the-reader-for-my-favorite-syntax)
This way, module implementors can decide to use whatever syntax variant
they prefer, while not having any side-effect on the code being read
from other files or modules. For illustration, here is an example that
makes use of my `guile-reader' thing:
--8<---------------cut here---------------start------------->8---
(define-module (module-with-reader)
#:reader (let* ((elisp-char-tr
(make-token-reader #\?
(token-reader-procedure
(standard-token-reader 'character)))))
(make-reader (cons elisp-char-tr
(map standard-token-reader
'(whitespace
sexp string number colon-keyword
semicolon-comment
symbol-upper-case symbol-lower-case
quote-quasiquote-unquote)))))
#:use-module (system reader))
(define-public (return-a-colon-keyword)
:a-keyword!)
(define-public (return-an-elisp-character)
?a)
--8<---------------cut here---------------end--------------->8---
For the module user, things are completely transparent:
$ guile -L .
guile> (read-options)
(keywords #f positions)
guile> (use-modules (module-with-reader))
guile> (return-a-colon-keyword)
#:a-keyword!
guile> (return-an-elisp-character)
#\a
guile> (module-reader (resolve-module '(module-with-reader)))
#<reader 301c2328>
guile> (module-reader (current-module))
#<primitive-procedure read>
The patch has a slight impact on `boot-9.scm' and `load.c'. The
procedure `primitive-load' (which is called by `load-module') is
modified in order to switch to the current module's reader as soon as
the current module changes.
Feedback welcome! ;-)
Thanks,
Ludovic.
ChangeLog entry for `libguile':
2005-10-13 Ludovic Courtès <[EMAIL PROTECTED]>
* load.c (scm_primitive_load): Switch to the current module's
reader when the current module changes.
* module.h (scm_module_index_reader): New macro.
(SCM_MODULE_READER): New macro.
ChangeLog entry for `ice-9':
2005-10-13 Ludovic Courtès <[EMAIL PROTECTED]>
* boot-9.scm (module-type): New field `reader'. Updated
callers of `module-constructor'.
(module-reader): New procedure.
(set-module-reader!): New procedure.
(process-define-module): Handle the `#:reader' keyword.
Index: ice-9/boot-9.scm
===================================================================
RCS file: /cvsroot/guile/guile/guile-core/ice-9/boot-9.scm,v
retrieving revision 1.351
diff -u -B -b -p -r1.351 boot-9.scm
--- ice-9/boot-9.scm 31 Jul 2005 23:36:50 -0000 1.351
+++ ice-9/boot-9.scm 13 Sep 2005 12:28:08 -0000
@@ -1185,7 +1185,8 @@
(make-record-type 'module
'(obarray uses binder eval-closure transformer name kind
duplicates-handlers duplicates-interface
- observers weak-observers observer-id)
+ observers weak-observers observer-id
+ reader)
%print-module))
;; make-module &opt size uses binder
@@ -1221,7 +1222,8 @@
uses binder #f #f #f #f #f #f
'()
(make-weak-value-hash-table 31)
- 0)))
+ 0
+ read)))
;; We can't pass this as an argument to module-constructor,
;; because we need it to close over a pointer to the module
@@ -1247,6 +1249,8 @@
(define set-module-name! (record-modifier module-type 'name))
(define module-kind (record-accessor module-type 'kind))
(define set-module-kind! (record-modifier module-type 'kind))
+(define module-reader (record-accessor module-type 'reader))
+(define set-module-reader! (record-modifier module-type 'reader))
(define module-duplicates-handlers
(record-accessor module-type 'duplicates-handlers))
(define set-module-duplicates-handlers!
@@ -2042,10 +2046,22 @@
(call-with-deferred-observers
(lambda ()
(module-use-interfaces! module (reverse reversed-interfaces))
+ ;; Evaluate the `#:reader' argument in the context of the module
+ ;; being defined.
+ (set-module-reader! module
+ (eval (module-reader module) module))
(module-export! module exports)
(module-replace! module replacements)
(module-re-export! module re-exports)))
(case (car kws)
+ ((#:reader)
+ ;; The argument to `#:reader' will be evaluated eventually.
+ (set-module-reader! module (cadr kws))
+ (loop (cddr kws)
+ reversed-interfaces
+ exports
+ re-exports
+ replacements))
((#:use-module #:use-syntax)
(or (pair? (cdr kws))
(unrecognized kws))
@@ -2138,7 +2154,7 @@
(set-car! (memq a (module-uses module)) i)
(module-local-variable i sym))))))
(module-constructor (make-hash-table 0) '() b #f #f name 'autoload #f #f
- '() (make-weak-value-hash-table 31) 0)))
+ '() (make-weak-value-hash-table 31) 0 read)))
;;; {Compiled module}
Index: libguile/load.c
===================================================================
RCS file: /cvsroot/guile/guile/guile-core/libguile/load.c,v
retrieving revision 1.86
diff -u -B -b -p -r1.86 load.c
--- libguile/load.c 23 May 2005 19:57:20 -0000 1.86
+++ libguile/load.c 13 Sep 2005 12:28:08 -0000
@@ -82,15 +82,29 @@ SCM_DEFINE (scm_primitive_load, "primiti
scm_call_1 (hook, filename);
{ /* scope */
+ SCM module = SCM_BOOL_F, reader = SCM_BOOL_F;
SCM port = scm_open_file (filename, scm_from_locale_string ("r"));
scm_frame_begin (SCM_F_FRAME_REWINDABLE);
scm_i_frame_current_load_port (port);
while (1)
{
- SCM form = scm_read (port);
+ SCM form;
+
+ if (scm_current_module () != module)
+ {
+ module = scm_current_module ();
+ reader = SCM_MODULE_READER (module);
+ }
+
+ if (reader == SCM_BOOL_F)
+ form = scm_read (port);
+ else
+ form = scm_call_1 (reader, port);
+
if (SCM_EOF_OBJECT_P (form))
break;
+
scm_primitive_eval_x (form);
}
Index: libguile/modules.h
===================================================================
RCS file: /cvsroot/guile/guile/guile-core/libguile/modules.h,v
retrieving revision 1.28
diff -u -B -b -p -r1.28 modules.h
--- libguile/modules.h 31 Jul 2005 23:36:14 -0000 1.28
+++ libguile/modules.h 13 Sep 2005 12:28:08 -0000
@@ -45,6 +45,7 @@ SCM_API scm_t_bits scm_module_tag;
#define scm_module_index_binder 2
#define scm_module_index_eval_closure 3
#define scm_module_index_transformer 4
+#define scm_module_index_reader 12
#define SCM_MODULE_OBARRAY(module) \
SCM_PACK (SCM_STRUCT_DATA (module) [scm_module_index_obarray])
@@ -56,6 +57,8 @@ SCM_API scm_t_bits scm_module_tag;
SCM_PACK (SCM_STRUCT_DATA (module)[scm_module_index_eval_closure])
#define SCM_MODULE_TRANSFORMER(module) \
SCM_PACK (SCM_STRUCT_DATA (module)[scm_module_index_transformer])
+#define SCM_MODULE_READER(module) \
+ SCM_PACK (SCM_STRUCT_DATA (module)[scm_module_index_reader])
SCM_API scm_t_bits scm_tc16_eval_closure;
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