[m-rev.] diff: single point of control for using_sprintf in C grades

[Julien Fischer]

Branches: master, 14.01

Provide a single point of control for the choice of implementation of
string.format in the C grades.  This choice is currently made in three
different spots.

library/string.m:
 	Define a new macro, ML_USE_SPRINTF, which expands to a Boolean that
 	controls which implementation for string.format is used in C grades.

Julien.

diff --git a/library/string.m b/library/string.m
index 36d39fe..5e64562 100644
--- a/library/string.m
+++ b/library/string.m
@@ -3107,7 +3107,7 @@ make_format(Flags, MaybeWidth, MaybePrec, LengthMod, Spec) =
      [will_not_call_mercury, promise_pure, thread_safe, will_not_modify_trail,
          does_not_affect_liveness, no_sharing],
  "
-    SUCCESS_INDICATOR = MR_TRUE;
+    SUCCESS_INDICATOR = ML_USE_SPRINTF;
  ").
  :- pragma foreign_proc("C#", using_sprintf,
      [will_not_call_mercury, promise_pure, thread_safe],
@@ -3136,7 +3136,7 @@ using_sprintf_for_char(_) :-
          does_not_affect_liveness, no_sharing],
  "
      /* sprintf %c specifier is inadequate for multi-byte UTF-8 characters. */
-    SUCCESS_INDICATOR = MR_is_ascii(Char);
+    SUCCESS_INDICATOR = ML_USE_SPRINTF && MR_is_ascii(Char);
  ").

  :- pred using_sprintf_for_string(string::in) is semidet.
@@ -3151,7 +3151,7 @@ using_sprintf_for_string(_) :-
  "
      const char *s;

-    SUCCESS_INDICATOR = MR_TRUE;
+    SUCCESS_INDICATOR = ML_USE_SPRINTF;
      for (s = Str; *s != '\\0'; s++) {
          /* sprintf %s specifier is inadequate for multi-byte UTF-8 characters,
           * if there is a field width or precision specified.
@@ -4134,6 +4134,15 @@ is_exponent('E').

  #include ""mercury_string.h""   /* for MR_allocate_aligned_string*() etc. */
  #include ""mercury_tags.h"" /* for MR_list_cons*() */
+
+/*
+** The following macro should expand to MR_TRUE if the C grades should 
+** implement string.format using C's sprintf function.
+** Setting it to MR_FALSE will cause string.format to use the Mercury
+** implementation of string formatting in C grades.
+*/
+#define ML_USE_SPRINTF MR_TRUE
+
  ").

  %-----------------------------------------------------------------------------%