[PATCH 1/1] scm_set_source_properties_x: optimize if only name, line, and/or col

[PATCH 1/1] scm_set_source_properties_x: optimize if only name, line, and/or col

[Rob Browning]

* libguile/srcprop.c (scm_set_source_properties_x): When only a subset
  of file, line, and column fields are specified, store the data as a
  srcprops object (tc16_srcprops) rather than an alist.
---

 Proposed for at least 3.x.  If we want some additional tests, then
 one option might be a public or private predicate to test for a
 srcprops object (at least for scheme level testing).

 libguile/srcprop.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/libguile/srcprop.c b/libguile/srcprop.c
index 0ebbfc301..fea68e031 100644
--- a/libguile/srcprop.c
+++ b/libguile/srcprop.c
@@ -168,8 +168,6 @@ SCM_DEFINE (scm_source_properties, "source-properties", 1, 0, 0,
 #define SCM_VALIDATE_NIM(pos, scm) \
   SCM_MAKE_VALIDATE_MSG (pos, scm, NIMP, "non-immediate")
 
-/* Perhaps this procedure should look through an alist
-   and try to make a srcprops-object...? */
 SCM_DEFINE (scm_set_source_properties_x, "set-source-properties!", 2, 0, 0,
             (SCM obj, SCM alist),
 	    "Install the association list @var{alist} as the source property\n"
@@ -177,9 +175,17 @@ SCM_DEFINE (scm_set_source_properties_x, "set-source-properties!", 2, 0, 0,
 #define FUNC_NAME s_scm_set_source_properties_x
 {
   SCM_VALIDATE_NIM (1, obj);
-
-  scm_weak_table_putq_x (scm_source_whash, obj, alist);
-
+  SCM fname = scm_assq_ref (alist, scm_sym_filename);
+  SCM col = scm_assq_ref (alist, scm_sym_column);
+  SCM line = scm_assq_ref (alist, scm_sym_line);
+  const int n = ((fname == SCM_BOOL_F) ? 0 : 1)
+    + ((col == SCM_BOOL_F) ? 0 : 1)
+    + ((line == SCM_BOOL_F) ? 0 : 1);
+
+  if (scm_ilength (alist) == n)
+    scm_i_set_source_properties_x (obj, line, col, fname);
+  else
+    scm_weak_table_putq_x (scm_source_whash, obj, alist);
   return alist;
 }
 #undef FUNC_NAME
-- 
2.29.2

Re: [PATCH 1/1] scm_set_source_properties_x: optimize if only name, line, and/or col

[Bruce Korb]

On 1/17/21 2:24 PM, Rob Browning wrote:
> * libguile/srcprop.c (scm_set_source_properties_x): When only a subset
>    of file, line, and column fields are specified, store the data as a
>    srcprops object (tc16_srcprops) rather than an alist.
> ---
>
>   Proposed for at least 3.x.  If we want some additional tests, then
>   one option might be a public or private predicate to test for a
>   srcprops object (at least for scheme level testing).
Does this mean I can swap out this code for something better now? I've 
disliked this code for years.

> static SCM
> ag_scm_c_eval_string_from_file_line(
>     char const * pzExpr, char const * pzFile, int line)
> {
>     SCM port = scm_open_input_string(AG_SCM_FROM_STR(pzExpr));
>
>     if (OPT_VALUE_TRACE >= TRACE_EVERYTHING)
>         fprintf(trace_fp, TRACE_EVAL_STRING, pzFile, line, pzExpr);
>
>     {
>         static SCM    file      = SCM_UNDEFINED;
>         static char * pzOldFile = NULL;
>
>         if ((pzOldFile == NULL) || (strcmp(pzOldFile, pzFile) != 0)) {
>             if (pzOldFile != NULL)
>                 AGFREE(pzOldFile);
>             AGDUPSTR(pzOldFile, pzFile, "scheme source");
>             file = AG_SCM_FROM_STR(pzFile);
>         }
>
>         {
>             SCM ln = scm_from_int(line);
>             scm_set_port_filename_x(port, file);
>             scm_set_port_line_x(port, ln);
>             scm_set_port_column_x(port, SCM_INUM0);
>         }
>     }
>
>     {
>         SCM ans = SCM_UNSPECIFIED;
>
>         /* Read expressions from that port; ignore the values.  */
>         for (;;) {
>             SCM form = scm_read(port);
>             if (SCM_EOF_OBJECT_P(form))
>                 break;
>             ans = scm_primitive_eval_x(form);
>         }
>
>         return ans;
>     }
> }