Merge pull request #598 from yallop/ocamlyacc-conflict-error

Reject conflicts in parsing/parser.mly

Makefile.shared

@@ -28,7 +28,7 @@ COMPFLAGS=-strict-sequence -principal -absname -w +a-4-9-41-42-44-45-48 -warn-er
           -bin-annot -safe-string -strict-formats $(INCLUDES)
 LINKFLAGS=
 
-YACCFLAGS=-v
+YACCFLAGS=-v --strict
 CAMLLEX=$(CAMLRUN) boot/ocamllex
 CAMLDEP=$(CAMLRUN) tools/ocamldep
 DEPFLAGS=$(INCLUDES)

man/ocamlyacc.m

@@ -79,6 +79,9 @@ instead of the default naming convention.
 .B \-q
 This option has no effect.
 .TP
+.B \--strict
+Reject grammars with conflicts.
+.TP
 .B \-v
 Generate a description of the parsing tables and a report on conflicts
 resulting from ambiguities in the grammar. The description is put in

yacc/defs.h

@@ -210,6 +210,7 @@ extern char tflag;
 extern char vflag;
 extern char qflag;
 extern char sflag;
+extern char eflag;
 extern char big_endian;
 
 extern char *myname;
@@ -335,6 +336,7 @@ extern void output (void);
 extern void over_unionized (char *u_cptr) Noreturn;
 extern void prec_redeclared (void);
 extern void polymorphic_entry_point(char *s) Noreturn;
+extern void forbidden_conflicts (void);
 extern void reader (void);
 extern void reflexive_transitive_closure (unsigned int *R, int n);
 extern void reprec_warning (char *s);

yacc/error.c

@@ -313,3 +313,11 @@ void polymorphic_entry_point(char *s)
             myname, s);
     done(1);
 }
+
+void forbidden_conflicts(void)
+{
+    fprintf(stderr,
+            "%s: the grammar has conflicts, but --strict was specified\n",
+            myname);
+    done(1);
+}

yacc/main.c

@@ -30,6 +30,7 @@ char rflag;
 char tflag;
 char vflag;
 char qflag;
+char eflag;
 char sflag;
 char big_endian;
 
@@ -160,7 +161,7 @@ void set_signals(void)
 
 void usage(void)
 {
-    fprintf(stderr, "usage: %s [-v] [-q] [-b file_prefix] filename\n",
+    fprintf(stderr, "usage: %s [-v] [--strict] [-q] [-b file_prefix] filename\n",
             myname);
     exit(1);
 }
@@ -184,6 +185,10 @@ void getargs(int argc, char **argv)
             return;
 
         case '-':
+            if (!strcmp (argv[i], "--strict")){
+              eflag = 1;
+              goto end_of_option;
+            }
             ++i;
             goto no_more_options;
 

yacc/mkpar.c

@@ -47,7 +47,11 @@ void make_parser(void)
     find_final_state();
     remove_conflicts();
     unused_rules();
-    if (SRtotal + RRtotal > 0) total_conflicts();
+    if (SRtotal + RRtotal > 0) {
+        total_conflicts();
+        if (eflag)
+            forbidden_conflicts();
+    }
     defreds();
 }