listener: don't complete on unbound symbols

This patch prevents Tab-completing on interned symbols that
have no binding.

The current behavior is, for instance:

  1> 'hamsandwich
  hamsandwich
  2> 'ham[Tab]
  2> 'hamsandwich ;; completes

The new behavior will not complete hamsandwich, because it has
no binding as a function or variable.

* parser.c (find_matching_syms): Treat the default case the
same as after '[': a function or variable binding is required,
or the symbol is not listed. Use fboundp instead of
lookup_fun.  They are the same, except in TXR 127 compat mode,
which includes macros under fboundp.

1 files changed, 3 insertions, 4 deletions

diff --git a/parser.c b/parser.c
index ba416c70..b791d7d8 100644
--- a/parser.c
+++ b/parser.c
@@ -957,14 +957,13 @@ static void find_matching_syms(lino_completions_t *cpl,
         if (!fboundp(sym) && !mboundp(sym) && !special_operator_p(sym))
           continue;
         break;
-      case '[':
-        if (!boundp(sym) && !lookup_fun(nil, sym))
-          continue;
-        break;
       case 'M':
       case 'S':
         break;
+      case '[':
       default:
+        if (!fboundp(sym) && !boundp(sym))
+          continue;
         break;
       }