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Use a fluid for the list of the reader's "hash procedures"

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This allows customizing the reader behavior for a dynamic extent more easily.

* libguile/read.c (scm_read_hash_procedures): Renamed to
  `scm_i_read_hash_procedures'.
  (scm_i_read_hash_procedures_ref, scm_i_read_hash_procedures_set_x):
  New (internal) accessor functions for the fluid.
  (scm_read_hash_extend, scm_get_hash_procedure): Use these accessor
  functions.
  (scm_init_read): Create the fluid, named `%read-hash-procedures' instead of
  the previous plain list `read-hash-procedures'.

* test-suite/tests/reader.test: Adapt the "R6RS/SRFI-30 block comment
  syntax overridden" test to make use of the fluid.

* module/ice-9/deprecated.scm (read-hash-procedures):
  New identifier macro -- backward-compatibility shim.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>
This commit is contained in:
Andreas Rottmann 2010-11-03 00:09:57 +01:00 • committed by Ludovic Courtès
commit d458073bc0
3 changed files with 52 additions and 24 deletions
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38
libguile/read.c
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@ -135,9 +135,21 @@ SCM_DEFINE (scm_read_options, "read-options-interface", 0, 1, 0,
}
#undef FUNC_NAME
/* An association list mapping extra hash characters to procedures. */
static SCM *scm_read_hash_procedures;
/* A fluid referring to an association list mapping extra hash
characters to procedures. */
static SCM *scm_i_read_hash_procedures;
static inline SCM
scm_i_read_hash_procedures_ref (void)
{
return scm_fluid_ref (*scm_i_read_hash_procedures);
}
static inline void
scm_i_read_hash_procedures_set_x (SCM value)
{
scm_fluid_set_x (*scm_i_read_hash_procedures, value);
}
/* Token readers. */
@ -1547,7 +1559,7 @@ SCM_DEFINE (scm_read_hash_extend, "read-hash-extend", 2, 0, 0,
proc, SCM_ARG2, FUNC_NAME);
/* Check if chr is already in the alist. */
this = *scm_read_hash_procedures;
this = scm_i_read_hash_procedures_ref ();
prev = SCM_BOOL_F;
while (1)
{
@ -1556,8 +1568,9 @@ SCM_DEFINE (scm_read_hash_extend, "read-hash-extend", 2, 0, 0,
/* not found, so add it to the beginning. */
if (scm_is_true (proc))
{
*scm_read_hash_procedures =
scm_cons (scm_cons (chr, proc), *scm_read_hash_procedures);
SCM new = scm_cons (scm_cons (chr, proc),
scm_i_read_hash_procedures_ref ());
scm_i_read_hash_procedures_set_x (new);
}
break;
}
@ -1569,8 +1582,8 @@ SCM_DEFINE (scm_read_hash_extend, "read-hash-extend", 2, 0, 0,
/* remove it. */
if (scm_is_false (prev))
{
*scm_read_hash_procedures =
SCM_CDR (*scm_read_hash_procedures);
SCM rest = SCM_CDR (scm_i_read_hash_procedures_ref ());
scm_i_read_hash_procedures_set_x (rest);
}
else
scm_set_cdr_x (prev, SCM_CDR (this));
@ -1594,7 +1607,7 @@ SCM_DEFINE (scm_read_hash_extend, "read-hash-extend", 2, 0, 0,
static SCM
scm_get_hash_procedure (int c)
{
SCM rest = *scm_read_hash_procedures;
SCM rest = scm_i_read_hash_procedures_ref ();
while (1)
{
@ -1738,8 +1751,13 @@ SCM_DEFINE (scm_file_encoding, "file-encoding", 1, 0, 0,
void
scm_init_read ()
{
scm_read_hash_procedures =
SCM_VARIABLE_LOC (scm_c_define ("read-hash-procedures", SCM_EOL));
SCM read_hash_procs;
read_hash_procs = scm_make_fluid ();
scm_fluid_set_x (read_hash_procs, SCM_EOL);
scm_i_read_hash_procedures =
SCM_VARIABLE_LOC (scm_c_define ("%read-hash-procedures", read_hash_procs));
scm_init_opts (scm_read_options, scm_read_opts);
#include "libguile/read.x"