* NEWS: The -g and --graph options now output graphs in Graphviz

DOT format, not VCG format.
* doc/bison.1: Likewise.
* doc/bison.texinfo (Understanding, Bison Options): Likewise.
* TODO: Remove Graphviz entry.
* src/Makefile.am (bison_SOURCES): Add graphviz.c and graphviz.h;
remove vcg.c, vcg.h, vcg_defaults.h.
* src/vcg.c, src/vcg.h, src/vcg_defaults.h: Remove.
* src/graphviz.c, src/graphviz.h: New files.
* src/files.c (compute_output_file_names): Output .dot, not .vcg.
* src/files.h: Make comment more generic.
* src/main.c (main): Likewise.
* src/print_graph.h: Likewise.
* src/getargs.c (usage): Make usage description more generic.
* src/print_graph.c: Include graphviz.h rather than vcg.h.
(static_graph, fgraph): Remove.  All uses changed to pass
arguments instead of sharing a static var.
(print_core, print_actions, print_state, print_graph):
Output graphviz format rather than VCG format.
* tests/.cvsignore: Remove *.vcg; add *.dot.
* tests/output.at: Expect *.dot files, not *.vcg files.

src/graphviz.c

@@ -0,0 +1,66 @@
+/* Output Graphviz specification of a state machine generated by Bison.
+
+   Copyright (C) 2006 Free Software Foundation, Inc.
+
+   This file is part of Bison, the GNU Compiler Compiler.
+
+   Bison is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   Bison is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with Bison; see the file COPYING.  If not, write to
+   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+   Boston, MA 02110-1301, USA.  */
+
+/* Written by Paul Eggert and Satya Kiran Popuri.  */
+
+#include <config.h>
+#include "system.h"
+
+#include <quotearg.h>
+
+#include "graphviz.h"
+
+/* Return an unambiguous printable representation for NAME, suitable
+   for C strings.  Use slot 2 since the user may use slots 0 and 1.  */
+
+static char const *
+quote (char const *name)
+{
+  return quotearg_n_style (2, c_quoting_style, name);
+}
+
+void
+start_graph (FILE *fout)
+{
+  fputs ("digraph Automaton{\n", fout);
+}
+
+void
+output_node (int id, char const *label, FILE *fout)
+{
+  fprintf (fout, "%d[label=%s]\n", id, quote (label));
+}
+
+void
+output_edge (int source, int destination, char const *label,
+	     char const *style, FILE *fout)
+{
+  fprintf (fout, "%d->%d[style=%s", source, destination, style);
+  if (label)
+    fprintf (fout, " label=%s", quote (label));
+  fputs ("]\n", fout);
+}
+
+void
+finish_graph (FILE *fout)
+{
+  fputs ("}\n", fout);
+}