[PATCH] "Name not found" vs. "No applicable method"

[Bob Rogers]

   The following patch makes Parrot_get_name report a different error
message if Parrot_MMD_search_default_func finds nothing, to distinguish
this from the case where nothing is found.  I am finding this helpful in
debugging.

   But this seems like a band-aid, for two reasons:

   1.  find_name can never return a MultiSub, and find_global doesn't
seem to work.  So I can't get a handle on a MultiSub built for me by
IMCC.

   2.  Even if I had it, I couldn't call it, because the dispatch is
done by find_name.

   Seems to me (IMHO) that the MultiSub invoke method is the right place
to do the actual dispatching, but I don't understand all the magic
involved.  Also, this would seem to interact with changes to the calling
conventions [1], so perhaps this patch is premature.

   Is there a MultiSub API, or one in the works?

                                        -- Bob Rogers
                                           http://rgrjr.dyndns.org/

[1]  Leo, "[PROPOSAL] call syntax abstraction", Tue, 03 May 2005
     13:58:14 +0200.

------------------------------------------------------------------------
Index: src/global.c
===================================================================
--- src/global.c        (revision 8008)
+++ src/global.c        (working copy)
@@ -195,6 +195,7 @@
 Parrot_get_name(Interp* interpreter, STRING *name)
 {
     PMC *g, *pad, *current_sub, *name_space;
+    int multi_sub_p = 0;
 
     pad = scratchpad_get_current(interpreter);
     g = scratchpad_find(interpreter, pad, name);
@@ -215,6 +216,7 @@
              * signature is currently passed in S1
              * see also imcc/pcc.c
              */
+            multi_sub_p = 1;
             g = Parrot_MMD_search_default_func(interpreter, name, REG_STR(1));
             if (g)
                 return g;
@@ -222,12 +224,18 @@
         else
             return g;
     }
-    if (PARROT_ERRORS_test(interpreter, PARROT_ERRORS_GLOBALS_FLAG))  {
+    if (! PARROT_ERRORS_test(interpreter, PARROT_ERRORS_GLOBALS_FLAG))  {
+        return pmc_new(interpreter, enum_class_Undef);
+    }
+    else if (multi_sub_p) {
+        /* we found the name, it's just that we couldn't dispatch. */
         real_exception(interpreter, NULL, E_NameError,
-                "Name '%Ss' not found", name);
+                       "No applicable '%Ss' method found", name);
     }
-
-    return pmc_new(interpreter, enum_class_Undef);
+    else {
+        real_exception(interpreter, NULL, E_NameError,
+                       "Name '%Ss' not found", name);
+    }
 }
 
 /*
Index: t/pmc/mmd.t
===================================================================
--- t/pmc/mmd.t (revision 8008)
+++ t/pmc/mmd.t (working copy)
@@ -476,7 +476,7 @@
 PerlSt ok 2
 PerlSt ok 3
 String ok 4
-Name 'p' not found/
+No applicable 'p' method found/
 OUT
 
 pir_output_is(<<'CODE', <<'OUT', "MMD on PMC types 3");