--- capa/capa51/pProj/capaGrammarDef.y	1999/11/08 22:30:02	1.6
+++ capa/capa51/pProj/capaGrammarDef.y	1999/12/07 19:10:47	1.7
@@ -1088,7 +1088,7 @@ append_warn(type,str) int type;char *str
 /*********** if *b is a constant symbol, destroy (free) b ********************/
 /*********** if *a is a var symbol, create a new symbol **********************/
 /*                 do not free(*a)     */
-/*           */
+/*  If either a or b is invalid it propagates the error up the parse tree    */
 Symbol *
 symbols_op(a, b, op) Symbol *a; Symbol *b; int op;
 {
@@ -1103,12 +1103,11 @@ if( a->s_type == IDENTIFIER || b->s_type
    if(a->s_type == IDENTIFIER) { /* a is IDENTIFIER */
      sprintf(warn_msg,"var \"%s\" not defined before use.\n", a->s_name);
      capa_msg(MESSAGE_ERROR,warn_msg);
-     return (b);
+     return (a);
    } else { /* b is IDENTIFIER */
-     sprintf(warn_msg,
-      "var \"%s\" not defined before use.\n",b->s_name);
+     sprintf(warn_msg,"var \"%s\" not defined before use.\n",b->s_name);
      capa_msg(MESSAGE_ERROR,warn_msg);
-     return (a);
+     return (b);
    }
  } else {  /* a and b are neither identifiers */
   if( (a->s_type == I_VAR) ||