Have Bison grammars parsed by a Bison grammar.

* src/reader.c, src/reader.h (prologue_augment): New.
* src/reader.c (copy_definition): Remove.
* src/reader.h, src/reader.c (gram_start_symbol_set, prologue_augment)
(grammar_symbol_append, grammar_rule_begin, grammar_midrule_action)
(grammar_current_rule_prec_set, grammar_current_rule_check)
(grammar_current_rule_symbol_append)
(grammar_current_rule_action_append): Export.
* src/parse-gram.y (symbol_list_new, symbol_list_symbol_append_
(symbol_list_action_append): Remove.
Hook the routines from reader.
* src/scan-gram.l: In INITIAL, characters and strings are tokens.
* src/system.h (ATTRIBUTE_NORETURN, ATTRIBUTE_UNUSED): Now.
* src/reader.c (read_declarations): Remove, unused.
* src/parse-gram.y: Handle the epilogue.
* src/reader.h, src/reader.c (gram_start_symbol_set): Rename as...
(grammar_start_symbol_set): this.
* src/scan-gram.l: Be sure to ``use'' yycontrol to keep GCC quiet.
* src/reader.c (readgram): Remove, unused.
(reader): Adjust to insert eoftoken and axiom where appropriate.
* src/reader.c (copy_dollar): Replace with...
* src/scan-gram.h (handle_dollar): this.
* src/parse-gram.y: Remove `%thong'.
* src/reader.c (copy_at): Replace with...
* src/scan-gram.h (handle_at): this.
* src/complain.h, src/complain.c (warn_at, complain_at, fatal_at):
New.
* src/scan-gram.l (YY_LINES): Keep lineno synchronized for the
time being.
* src/reader.h, src/reader.c (grammar_rule_end): New.
* src/parse.y (current_type, current_class): New.
Implement `%nterm', `%token' support.
Merge `%term' into `%token'.
(string_as_id): New.
* src/symtab.h, src/symtab.c (symbol_make_alias): Don't pass the
type name.
* src/parse-gram.y: Be sure to handle properly the beginning of
rules.
* src/parse-gram.y: Handle %type.
* src/reader.c (grammar_rule_end): Call grammar_current_rule_check.
* src/parse-gram.y: More directives support.
* src/options.c: No longer handle source directives.
* src/parse-gram.y: Fix %output.
* src/parse-gram.y: Handle %union.
Use the prologue locations.
* src/reader.c (parse_union_decl): Remove.
* src/reader.h, src/reader.c (epilogue_set): New.
* src/parse-gram.y: Use it.
* data/bison.simple, data/bison.c++: b4_stype is now either not
defined, then default to int, or to the contents of %union,
without `union' itself.
Adjust.
* src/muscle_tab.c (muscle_init): Don't predefine `stype'.
* src/output.c (actions_output): Don't output braces, as they are
already handled by the scanner.
* src/scan-gram.l (SC_CHARACTER): Set the user_token_number of
characters to themselves.
* tests/reduce.at (Reduced Automaton): End the grammars with %% so
that the epilogue has a proper #line.
* src/parse-gram.y: Handle precedence/associativity.
* src/symtab.c (symbol_precedence_set): Requires the symbol to be
a terminal.
* src/scan-gram.l (SC_BRACED_CODE): Catch strings and characters.
* tests/calc.at: Do not use `%token "foo"' as it makes not sense
at all to define terminals that cannot be emitted.
* src/scan-gram.l: Escape M4 characters.
* src/scan-gram.l: Working properly with escapes in user
strings/characters.
* tests/torture.at (AT_DATA_TRIANGULAR_GRAMMAR)
(AT_DATA_HORIZONTAL_GRAMMAR): Respect the `%token ID NUM STRING'
grammar.
Use more modest sizes, as for the time being the parser does not
release memory, and therefore the process swallows a huge amount
of memory.
* tests/torture.at (AT_DATA_LOOKAHEADS_GRAMMAR): Adjust to the
stricter %token grammar.
* src/symtab.h (associativity): Add `undef_assoc'.
(symbol_precedence_set): Do nothing when passed an undef_assoc.
* src/symtab.c (symbol_check_alias_consistence): Adjust.
* tests/regression.at (Invalid %directive): Remove, as it is now
meaningless.
(Invalid inputs): Adjust to the new error messages.
(Token definitions): The new grammar doesn't allow too many
eccentricities.
* src/lex.h, src/lex.c: Remove.
* src/reader.c (lastprec, skip_to_char, read_signed_integer)
(copy_character, copy_string2, copy_string, copy_identifier)
(copy_comment, parse_token_decl, parse_type_decl, parse_assoc_decl)
(parse_muscle_decl, parse_dquoted_param, parse_skel_decl)
(parse_action): Remove.
* po/POTFILES.in: Adjust.

src/symtab.h

@@ -29,6 +29,7 @@
 /* Associativity values for tokens and rules.  */
 typedef enum
 {
+  undef_assoc,
   right_assoc,
   left_assoc,
   non_assoc
@@ -84,15 +85,15 @@ struct symbol_s
 /* Fetch (or create) the symbol associated to KEY.  */
 symbol_t *getsym PARAMS ((const char *key));
 
-/* Declare the new SYMBOL.  Make it an alias of SYMVAL, and type */
-/* them with TYPENAME.                                           */
-void symbol_make_alias PARAMS ((symbol_t *symbol, symbol_t *symval,
-				char *typename));
+/* Declare the new SYMBOL.  Make it an alias of SYMVAL.  */
+void symbol_make_alias PARAMS ((symbol_t *symbol, symbol_t *symval));
 
-/* Set the TYPE_NAME associated to SYMBOL. */
+/* Set the TYPE_NAME associated to SYMBOL. Does nothing if passed 0 as
+   TYPE_NAME.  */
 void symbol_type_set PARAMS ((symbol_t *symbol, char *type_name));
 
-/* Set the PRECEDENCE associated to SYMBOL.  */
+/* Set the PRECEDENCE associated to SYMBOL.  Ensures that SYMBOL is a
+   terminal.  Does nothing if invoked with UNDEF_ASSOC as ASSOC.  */
 void symbol_precedence_set PARAMS ((symbol_t *symbol,
 				    int prec, associativity assoc));
 
@@ -131,8 +132,8 @@ void symbols_do PARAMS ((symbol_processor processor, void *processor_data));
 /* Free all the memory allocated for symbols.  */
 void symbols_free PARAMS ((void));
 
-/* Check that all the symbols are defined.  Report any undefined */
-/* symbols and consider them nonterminals.                       */
+/* Check that all the symbols are defined.  Report any undefined
+   symbols and consider them nonterminals.  */
 void symbols_check_defined PARAMS ((void));
 
 /* Perform various sanity checks, assign symbol numbers, and set up