* src/LR0.h: New file.

[bison.git] / src / bison.s1

diff --git a/src/bison.s1 b/src/bison.s1
index 8de2ccd341922aaa5f18a53edab67438b2e03bf4..62859b2724af262a4b5dd358dcb313ca6a51a150 100644 (file)
--- a/src/bison.s1
+++ b/src/bison.s1
@@ -132,24 +132,26 @@ while (0)
 # endif /* not YYLSP_NEEDED */
 #endif
 
-/* If nonreentrant, generate the variables here */
+/* If nonreentrant, generate the variables here. */
 
 #ifndef YYPURE
+/* The lookahead symbol.  */
+int    yychar;
 
-int    yychar;                 /*  the lookahead symbol                */
-YYSTYPE        yylval;                 /*  the semantic value of the           */
-                               /*  lookahead symbol                    */
+/* The semantic value of the lookahead symbol. */
+YYSTYPE        yylval;
 
 # ifdef YYLSP_NEEDED
-YYLTYPE yylloc;                        /*  location data for the lookahead     */
-                               /*  symbol                              */
+/* Location data for the lookahead symbol.  */
+YYLTYPE yylloc;
 # endif
 
-int yynerrs;                   /*  number of parse errors so far       */
+/* Number of parse errors so far.  */
+int yynerrs;
 #endif  /* not YYPURE */
 
 
-#if YYDEBUG != 0
+#if YYDEBUG
 int yydebug;                   /*  nonzero means print parse trace     */
 
   /* [The following comment makes no sense to me.  Could someone
@@ -307,10 +309,15 @@ yyparse(YYPARSE_PARAM_ARG)
 #endif
 
 
-  /* The variable used to return semantic values from the action
-     routines.  */
+  /* The variables used to return semantic value and location from the
+     action routines.  */
   YYSTYPE yyval;
+# ifdef YYLSP_NEEDED
+  YYLTYPE yyloc;
+# endif
 
+  /* When reducing, the number of symbols on the RHS of the reduced
+     rule. */
   int yylen;
 
   if (yydebug)
@@ -463,16 +470,20 @@ yynewstate:
     {
       yychar1 = YYTRANSLATE(yychar);
 
+#if YYDEBUG
+     /* We have to keep this `#if YYDEBUG', since we use variables
+       which are defined only if `YYDEBUG' is set.  */
       if (yydebug)
        {
          fprintf (stderr, "Next token is %d (%s", yychar, yytname[yychar1]);
-         /* Give the individual parser a way to print the precise meaning
-            of a token, for further debugging info.  */
+         /* Give the individual parser a way to print the precise
+            meaning of a token, for further debugging info.  */
 # ifdef YYPRINT
          YYPRINT (stderr, yychar, yylval);
 # endif
          fprintf (stderr, ")\n");
        }
+#endif
     }
 
   yyn += yychar1;
@@ -502,9 +513,10 @@ yynewstate:
     YYACCEPT;
 
   /* Shift the lookahead token.  */
-
+#if YYDEBUG
   if (yydebug)
     fprintf (stderr, "Shifting token %d (%s), ", yychar, yytname[yychar1]);
+#endif
 
   /* Discard the token being shifted unless it is eof.  */
   if (yychar != YYEOF)
@@ -531,8 +543,27 @@ yydefault:
 /* Do a reduction.  yyn is the number of a rule to reduce with.  */
 yyreduce:
   yylen = yyr2[yyn];
+  /* Implement default value of the action:
+     `{dollar}{dollar} = {dollar}1'. */
+  if (yylen > 0)
+      yyval = yyvsp[1-yylen];
+#ifdef YYLSP_NEEDED
+  /* Implement default location.  If the rhs is empty, extend YYLOC to
+     YYLLOC, which corresponds to the current token, otherwise
+     implement `@{dollar} = Starts at @1, ends at @YYLEN'.  */
   if (yylen > 0)
-    yyval = yyvsp[1-yylen]; /* implement default value of the action */
+    {
+      yyloc = yylsp[1-yylen];
+      yyloc.last_line = yylsp[0].last_line;
+      yyloc.last_column = yylsp[0].last_column;
+    }
+  else
+    {
+      yyloc.last_line = yylsp[0].last_line;
+      yyloc.last_column = yylsp[0].last_column;
+      yyloc.text = 0;
+    }
+#endif
 
 #if YYDEBUG
   /* We have to keep this `#if YYDEBUG', since we use variables which
@@ -569,28 +600,13 @@ $   /* the action file gets copied in in place of this dollarsign */
     }
 
   *++yyvsp = yyval;
-
 #ifdef YYLSP_NEEDED
-  yylsp++;
-  if (yylen == 0)
-    {
-      yylsp->first_line = yylloc.first_line;
-      yylsp->first_column = yylloc.first_column;
-      yylsp->last_line = (yylsp-1)->last_line;
-      yylsp->last_column = (yylsp-1)->last_column;
-      yylsp->text = 0;
-    }
-  else
-    {
-      yylsp->last_line = (yylsp+yylen-1)->last_line;
-      yylsp->last_column = (yylsp+yylen-1)->last_column;
-    }
+  *++yylsp = yyloc;
 #endif
 
-  /* Now "shift" the result of the reduction.
-     Determine what state that goes to,
-     based on the state we popped back to
-     and the rule number reduced by.  */
+  /* Now `shift' the result of the reduction.  Determine what state
+     that goes to, based on the state we popped back to and the rule
+     number reduced by.  */
 
   yyn = yyr1[yyn];
 
@@ -624,10 +640,14 @@ yyerrlab:   /* here on detecting error */
               x < (sizeof(yytname) / sizeof(char *)); x++)
            if (yycheck[x + yyn] == x)
              size += strlen(yytname[x]) + 15, count++;
-         msg = (char *) malloc(size + 15);
+         size += strlen ("parse error, unexpected `") + 1;
+         size += strlen (yytname[YYTRANSLATE (yychar)]);
+         msg = (char *) malloc (size);
          if (msg != 0)
            {
-             strcpy(msg, "parse error");
+             strcpy (msg, "parse error, unexpected `");
+             strcat (msg, yytname[YYTRANSLATE (yychar)]);
+             strcat (msg, "'");
 
              if (count < 5)
                {
@@ -636,21 +656,21 @@ yyerrlab:   /* here on detecting error */
                       x < (sizeof(yytname) / sizeof(char *)); x++)
                    if (yycheck[x + yyn] == x)
                      {
-                       strcat(msg, count == 0 ? ", expecting `" : " or `");
-                       strcat(msg, yytname[x]);
-                       strcat(msg, "'");
+                       strcat (msg, count == 0 ? ", expecting `" : " or `");
+                       strcat (msg, yytname[x]);
+                       strcat (msg, "'");
                        count++;
                      }
                }
-             yyerror(msg);
-             free(msg);
+             yyerror (msg);
+             free (msg);
            }
          else
            yyerror ("parse error; also virtual memory exceeded");
        }
       else
 #endif /* YYERROR_VERBOSE */
-       yyerror("parse error");
+       yyerror ("parse error");
     }
 
   goto yyerrlab1;
@@ -663,11 +683,11 @@ yyerrlab1:   /* here on error raised explicitly by an action */
       /* return failure if at end of input */
       if (yychar == YYEOF)
        YYABORT;
-
+#if YYDEBUG
       if (yydebug)
        fprintf (stderr, "Discarding token %d (%s).\n",
                 yychar, yytname[yychar1]);
-
+#endif
       yychar = YYEMPTY;
     }