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-rw-r--r--libguile/ChangeLog3
-rw-r--r--libguile/options.c21
-rw-r--r--libguile/options.h1
3 files changed, 22 insertions, 3 deletions
diff --git a/libguile/ChangeLog b/libguile/ChangeLog
index c323294ff..58f662cf1 100644
--- a/libguile/ChangeLog
+++ b/libguile/ChangeLog
@@ -1,5 +1,8 @@
2007-01-19 Han-Wen Nienhuys <hanwen@lilypond.org>
+ * options.c (scm_options_try): new function. This allows error
+ reporting before changing options in a critical section.
+
* srcprop.c: use double cell for storing source-properties. Put
filename in the plist, and share between srcprops if possible.
Remove specialized storage.
diff --git a/libguile/options.c b/libguile/options.c
index 412192fb9..ae75e1318 100644
--- a/libguile/options.c
+++ b/libguile/options.c
@@ -164,9 +164,14 @@ options_length (scm_t_option options[])
* formed option setting, i. e. if for every non-boolean option a value is
* given. For this reason, the function applies all changes to a copy of the
* original setting in memory. Only if 'args' was successfully processed,
- * the new setting will overwrite the old one. */
+ * the new setting will overwrite the old one.
+ *
+ * If DRY_RUN is set, don't change anything. This is useful for trying out an option
+ * before entering a critical section.
+ */
static void
-change_option_setting (SCM args, scm_t_option options[], const char *s)
+change_option_setting (SCM args, scm_t_option options[], const char *s,
+ int dry_run)
{
unsigned int i;
SCM locally_protected_args = args;
@@ -214,6 +219,9 @@ change_option_setting (SCM args, scm_t_option options[], const char *s)
args = SCM_CDR (args);
}
+ if (dry_run)
+ return;
+
for (i = 0; options[i].name; ++i)
{
if (options[i].type == SCM_OPTION_SCM)
@@ -235,6 +243,13 @@ change_option_setting (SCM args, scm_t_option options[], const char *s)
SCM
scm_options (SCM args, scm_t_option options[], const char *s)
{
+ return scm_options_try (args, options, s, 0);
+}
+
+SCM
+scm_options_try (SCM args, scm_t_option options[], const char *s,
+ int dry_run)
+{
if (SCM_UNBNDP (args))
return get_option_setting (options);
else if (!SCM_NULL_OR_NIL_P (args) && !scm_is_pair (args))
@@ -247,7 +262,7 @@ scm_options (SCM args, scm_t_option options[], const char *s)
SCM old_setting;
SCM_ASSERT (scm_is_true (scm_list_p (args)), args, 1, s);
old_setting = get_option_setting (options);
- change_option_setting (args, options, s);
+ change_option_setting (args, options, s, dry_run);
return old_setting;
}
}
diff --git a/libguile/options.h b/libguile/options.h
index 71761245e..5b9664958 100644
--- a/libguile/options.h
+++ b/libguile/options.h
@@ -40,6 +40,7 @@ typedef struct scm_t_option
#define SCM_OPTION_SCM 2
+SCM_API SCM scm_options_try (SCM args, scm_t_option options[], const char *s, int dry_run);
SCM_API SCM scm_options (SCM, scm_t_option [], const char*);
SCM_API void scm_init_opts (SCM (*) (SCM), scm_t_option []);
SCM_API void scm_init_options (void);