adapted to allow for user intervention before error recovery

util/LLgen/src/LLgen.g

@@ -127,16 +127,23 @@ def			{	register string p; }
 				start = ff;
 			}
 	| C_LEXICAL C_IDENT
+	  /*
+	   * Declaration of a name for the lexical analyser.
+	   * May appear only once
+	   */
 			{	if (!lexical) {
 					lexical = store(lextoken.t_string);
 				}
 				else	error(linecount,"Duplicate %%lexical");
 			}
 	  ';'
-	  /*
-	   * Declaration of a name for the lexical analyser.
-	   * May appear only once
-	   */
+	| C_ONERROR C_IDENT
+			{	if (! onerror) {
+					onerror = store(lextoken.t_string);
+				}
+				else	error(linecount,"Duplicate %%onerror");
+			}
+	  ';'
 	| action(0)	{	acount++; }
 	  /*
 	   * A global C-declaration

util/LLgen/src/extern.h

@@ -63,6 +63,7 @@ extern struct order *sorder, *porder;
 extern string	e_noopen;	/* Error message string used often */
 extern int	verbose;	/* Level of verbosity */
 extern string	lexical;	/* name of lexical analyser */
+extern string	onerror;	/* name of user error handler */
 extern int	ntneeded;	/* ntneeded = 1 if nonterminals are included
 				 * in the sets.
 				 */

util/LLgen/src/gencode.c

@@ -168,12 +168,13 @@ genrecovery() {
 		}
 	}
 	i = maxptr - setptr;
-	fprintf(fpars,
+	fprintf(f,
 "#define LL_LEXI %s\n#define LL_SSIZE %d\n#define LL_NSETS %d\n#define LL_NTERMINALS %d\n",
 		  lexical,
 		  nbytes,
 		  i > 0 ? i : 1,
 		  ntokens);
+	if (onerror) fprintf(f,"#define LL_USERHOOK %s\n", onerror);
 	/* Now generate the routines that call the startsymbols */
 	for (st = start; st; st = st->ff_next) {
 		fputs(st->ff_name, f);
@@ -471,8 +472,11 @@ rulecode(p,safety,mustscan,mustpop) register p_gram p; {
 				genpop(findindex(n->n_contains));
 			}
 			if (g_gettype(n->n_rule) == EORULE &&
-			    safety == getntout(n) &&
-			    ! g_getnpar(p)) break;
+			    safety <= getntout(n) &&
+			    ! g_getnpar(p)) {
+				safety = getntout(n);
+				break;
+			}
 			fprintf(f,"L%d_%s(\n",g_getnont(p), n->n_name);
 			if (g_getnpar(p)) {
 				controlline();

util/LLgen/src/global.c

@@ -58,6 +58,7 @@ string	f_input;
 string	e_noopen = "Cannot open %s";
 int	verbose;
 string	lexical;
+string	onerror;
 int	ntneeded;
 int	ntprint;
 # ifndef NDEBUG

util/LLgen/src/tokens.g

@@ -67,6 +67,7 @@ STATIC string	vallookup();
 %token	C_PERSISTENT ;
 %token	C_FIRST ;
 %token	C_LEXICAL ;
+%token	C_ONERROR ;
 %token	C_AVOID ;
 %token	C_PREFER ;
 %token	C_DEFAULT ;
@@ -100,6 +101,7 @@ static t_keyw resword[] = {
 	{ "first",	C_FIRST	},
 	{ "start",	C_START	},
 	{ "lexical",	C_LEXICAL	},
+	{ "onerror",	C_ONERROR	},
 	{ 0,		0	}
 };