Extract the parsing of user actions from the grammar scanner.

As a consequence, the relation between the grammar scanner and
parser is much simpler.  We can also split "composite tokens" back
into simple tokens.
* src/gram.h (ITEM_NUMBER_MAX, RULE_NUMBER_MAX): New.
* src/scan-gram.l (add_column_width, adjust_location): Move to and
rename as...
* src/location.h, src/location.c (add_column_width)
(location_compute): these.
Fix the column count: the initial column is 0.
(location_print): Be robust to ending column being 0.
* src/location.h (boundary_set): New.
* src/main.c: Adjust to scanner_free being renamed as
gram_scanner_free.
* src/output.c: Include scan-code.h.
* src/parse-gram.y: Include scan-gram.h and scan-code.h.
Use boundary_set.
(PERCENT_DESTRUCTOR, PERCENT_PRINTER, PERCENT_INITIAL_ACTION)
(PERCENT_LEX_PARAM, PERCENT_PARSE_PARAM): Remove the {...} part,
which is now, again, a separate token.
Adjust all dependencies.
Whereever actions with $ and @ are used, use translate_code.
(action): Remove this nonterminal which is now useless.
* src/reader.c: Include assert.h, scan-gram.h and scan-code.h.
(grammar_current_rule_action_append): Use translate_code.
(packgram): Bound check ruleno, itemno, and rule_length.
* src/reader.h (gram_in, gram__flex_debug, scanner_cursor)
(last_string, last_braced_code_loc, max_left_semantic_context)
(scanner_initialize, scanner_free, scanner_last_string_free)
(gram_out, gram_lineno, YY_DECL_): Move to...
* src/scan-gram.h: this new file.
(YY_DECL): Rename as...
(GRAM_DECL): this.
* src/scan-code.h, src/scan-code.l, src/scan-code-c.c: New.
* src/scan-gram.l (gram_get_lineno, gram_get_in, gram_get_out):
(gram_get_leng, gram_get_text, gram_set_lineno, gram_set_in):
(gram_set_out, gram_get_debug, gram_set_debug, gram_lex_destroy):
Move these declarations, and...
(obstack_for_string, STRING_GROW, STRING_FINISH, STRING_FREE):
these to...
* src/flex-scanner.h: this new file.
* src/scan-gram.l (rule_length, rule_length_overflow)
(increment_rule_length): Remove.
(last_braced_code_loc): Rename as...
(gram_last_braced_code_loc): this.
Adjust to the changes of the parser.
Move all the handling of $ and @ into...
* src/scan-code.l: here.
* src/scan-gram.l (handle_dollar, handle_at): Remove.
(handle_action_dollar, handle_action_at): Move to...
* src/scan-code.l: here.
* src/Makefile.am (bison_SOURCES): Add flex-scanner.h,
scan-code.h, scan-code-c.c, scan-gram.h.
(EXTRA_bison_SOURCES): Add scan-code.l.
(BUILT_SOURCES): Add scan-code.c.
(yacc): Be robust to white spaces.
* tests/conflicts.at, tests/input.at, tests/reduce.at,
* tests/regression.at: Adjust the column numbers.
* tests/regression.at: Adjust the error message.

src/scan-code.h

@@ -0,0 +1,47 @@
+/* Bison Action Scanner
+
+   Copyright (C) 2006 Free Software Foundation, Inc.
+
+   This file is part of Bison, the GNU Compiler Compiler.
+
+   This program 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 of the License, or
+   (at your option) any later version.
+
+   This program 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 this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+   02110-1301  USA
+*/
+
+#ifndef SCAN_CODE_H_
+# define SCAN_CODE_H_
+
+# include "location.h"
+# include "symlist.h"
+
+/* Keeps track of the maximum number of semantic values to the left of
+   a handle (those referenced by $0, $-1, etc.) are required by the
+   semantic actions of this grammar. */
+extern int max_left_semantic_context;
+
+void code_scanner_free (void);
+
+/* The action A contains $$, $1 etc. referring to the values
+   of the rule R. */
+const char *translate_rule_action (symbol_list *r, const char *a, location l);
+
+/* The action A refers to $$ and @$ only, referring to a symbol. */
+const char *translate_symbol_action (const char *a, location l);
+
+/* The action contains no special escapes, just protect M4 special
+   symbols.  */
+const char *translate_code (const char *a, location l);
+
+#endif /* !SCAN_CODE_H_ */