* api-evaluation.texi (Loading): Document custom reader.

* boot-9.scm (load-module): Support an optional custom reader arg,
implemented by passing on to r4rs's load.

* r4rs.scm (load): Support an optional custom reader arg,
implemented by passing on to primitive-load.

* load.c (the_reader, the_reader_fluid_num): New.
(scm_primitive_load): Support custom reader.
(scm_init_load): Init the_reader and the_reader_fluid_num; export
the_reader as `current-reader'.

doc/ref/ChangeLog

@@ -1,3 +1,7 @@
+2005-12-14  Neil Jerram  <neil@ossau.uklinux.net>
+
+	* api-evaluation.texi (Loading): Document custom reader.
+
 2005-12-06  Marius Vollmer  <mvo@zagadka.de>
 
 	* api-init.texi, api-scheduling.texi, libguile-concepts.texi:

doc/ref/api-evaluation.texi

@@ -409,12 +409,24 @@ the current module.
 @subsection Loading Scheme Code from File
 
 @rnindex load
-@deffn {Scheme Procedure} load filename
+@deffn {Scheme Procedure} load filename [reader]
 Load @var{filename} and evaluate its contents in the top-level
-environment.  The load paths are not searched.  If the variable
-@code{%load-hook} is defined, it should be bound to a procedure that
-will be called before any code is loaded.  See documentation for
-@code{%load-hook} later in this section.
+environment.  The load paths are not searched.
+
+@var{reader} if provided should be either @code{#f}, or a procedure with
+the signature @code{(lambda (port) @dots{})} which reads the next
+expression from @var{port}.  If @var{reader} is @code{#f} or absent,
+Guile's built-in @code{read} procedure is used (@pxref{Scheme Read}).
+
+The @var{reader} argument takes effect by setting the value of the
+@code{current-reader} fluid (see below) before loading the file, and
+restoring its previous value when loading is complete.  The Scheme code
+inside @var{filename} can itself change the current reader procedure on
+the fly by setting @code{current-reader} fluid.
+
+If the variable @code{%load-hook} is defined, it should be bound to a
+procedure that will be called before any code is loaded.  See
+documentation for @code{%load-hook} later in this section.
 @end deffn
 
 @deffn {Scheme Procedure} load-from-path filename
@@ -452,6 +464,15 @@ in the @code{%load-extensions} list; @code{%search-load-path}
 will try each extension automatically.
 @end deffn
 
+@defvar current-reader
+@code{current-reader} holds the read procedure that is currently being
+used by the above loading procedures to read expressions (from the file
+that they are loading).  @code{current-reader} is a fluid, so it has an
+independent value in each dynamic root and should be read and set using
+@code{fluid-ref} and @code{fluid-set!} (@pxref{Fluids and Dynamic
+States}).
+@end defvar
+
 @defvar %load-hook
 A procedure to be called @code{(%load-hook @var{filename})} whenever a
 file is loaded, or @code{#f} for no such call.  @code{%load-hook} is

ice-9/ChangeLog

@@ -1,3 +1,11 @@
+2005-12-14  Neil Jerram  <neil@ossau.uklinux.net>
+
+	* boot-9.scm (load-module): Support an optional custom reader arg,
+	implemented by passing on to r4rs's load.
+
+	* r4rs.scm (load): Support an optional custom reader arg,
+	implemented by passing on to primitive-load.
+
 2005-12-06  Marius Vollmer  <mvo@zagadka.de>
 
 	From Stephen Compall.

ice-9/boot-9.scm

@@ -1635,17 +1635,19 @@
 
 (define basic-load load)
 
-(define (load-module filename)
+(define (load-module filename . reader)
   (save-module-excursion
    (lambda ()
      (let ((oldname (and (current-load-port)
 			 (port-filename (current-load-port)))))
-       (basic-load (if (and oldname
-			    (> (string-length filename) 0)
-			    (not (char=? (string-ref filename 0) #\/))
-			    (not (string=? (dirname oldname) ".")))
-		       (string-append (dirname oldname) "/" filename)
-		       filename))))))
+       (apply basic-load
+	      (if (and oldname
+		       (> (string-length filename) 0)
+		       (not (char=? (string-ref filename 0) #\/))
+		       (not (string=? (dirname oldname) ".")))
+		  (string-append (dirname oldname) "/" filename)
+		  filename)
+	      reader)))))
 
 
 

ice-9/r4rs.scm

@@ -206,6 +206,8 @@ procedures, their behavior is implementation dependent."
 
 (set! %load-hook %load-announce)
 
-(define (load name)
-  (start-stack 'load-stack
-	       (primitive-load name)))
+(define (load name . reader)
+  (with-fluid* current-reader (and (pair? reader) (car reader))
+    (lambda ()
+      (start-stack 'load-stack
+		   (primitive-load name)))))

libguile/ChangeLog

@@ -1,5 +1,10 @@
 2005-12-14  Neil Jerram  <neil@ossau.uklinux.net>
 
+	* load.c (the_reader, the_reader_fluid_num): New.
+	(scm_primitive_load): Support custom reader.
+	(scm_init_load): Init the_reader and the_reader_fluid_num; export
+	the_reader as `current-reader'.
+
 	* scmsigs.c (do_read_without_guile): Use the "raw_data" passed in
 	(rather than an uninitialized pointer on the stack).
 

libguile/load.c

@@ -42,6 +42,7 @@
 
 #include "libguile/validate.h"
 #include "libguile/load.h"
+#include "libguile/fluids.h"
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -61,6 +62,10 @@
    Applied to the full name of the file.  */
 static SCM *scm_loc_load_hook;
 
+/* The current reader (a fluid).  */
+static SCM the_reader = SCM_BOOL_F;
+static size_t the_reader_fluid_num = 0;
+
 SCM_DEFINE (scm_primitive_load, "primitive-load", 1, 0, 0, 
            (SCM filename),
 	    "Load the file named @var{filename} and evaluate its contents in\n"
@@ -88,9 +93,19 @@ SCM_DEFINE (scm_primitive_load, "primitive-load", 1, 0, 0,
 
     while (1)
       {
-	SCM form = scm_read (port);
+	SCM reader, form;
+
+	/* Lookup and use the current reader to read the next
+	   expression. */
+	reader = SCM_FAST_FLUID_REF (the_reader_fluid_num);
+	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);
       }
 
@@ -501,6 +516,11 @@ scm_init_load ()
 						  scm_nullstr)));
   scm_loc_load_hook = SCM_VARIABLE_LOC (scm_c_define ("%load-hook", SCM_BOOL_F));
 
+  the_reader = scm_make_fluid ();
+  the_reader_fluid_num = SCM_FLUID_NUM (the_reader);
+  SCM_FAST_FLUID_SET_X (the_reader_fluid_num, SCM_BOOL_F);
+  scm_c_define("current-reader", the_reader);
+
   init_build_info ();
 
 #include "libguile/load.x"