For each start symbol, generate a parsing function with a richer
return value than the usual of yyparse. Reserve a place for the
returned semantic value, in order to avoid having to pass a pointer as
argument to "return" that value. This also makes the call to the
parsing function independent of whether a given start-symbol is typed.
For instance, if the grammar file contains:
%type <int> expression
%start input expression
(so "input" is valueless) we get
typedef struct
{
int yystatus;
} yyparse_input_t;
yyparse_input_t yyparse_input (void);
typedef struct
{
int yyvalue;
int yystatus;
} yyparse_expression_t;
yyparse_expression_t yyparse_expression (void);
This commit also changes the implementation of the parser termination:
when there are multiple start symbols, it is the initial rules that
explicitly YYACCEPT. They do that after having exported the
start-symbol's value (if it is typed):
switch (yyn)
{
case 1: /* $accept: YY_EXPRESSION expression $end */
{ ((*yyvalue).TOK_expression) = (yyvsp[-1].TOK_expression); YYACCEPT; }
break;
case 2: /* $accept: YY_INPUT input $end */
{ YYACCEPT; }
break;
I have tried several ways to deal with termination, and this is the
one that appears the best one to me. It is also the most natural.
* src/scan-code.h, src/scan-code.l (obstack_for_actions): New.
* src/reader.c (grammar_rule_check_and_complete): Generate the actions
of the rules for each start symbol.
* data/skeletons/bison.m4 (b4_symbol_slot): New, with safer semantics
than type and type_tag.
* data/skeletons/yacc.c (b4_accept): New.
Generates the body of the action of the start rules.
(_b4_declare_sub_yyparse): For each start symbol define a dedicated
return type for its parsing function.
Adjust the declaration of its parsing function.
(_b4_define_sub_yyparse): Adjust the definition of the function.
* examples/c/lexcalc/parse.y: Check the case of valueless symbols.
* examples/c/lexcalc/lexcalc.test: Check start symbols.
* README-hacking.md (Working from the Repository): Make it first to
make it easier to find the instructions to build from the repo.
(Implementation Notes): New.
* README: Provide more links.
This should have been done in 3.6, but I wanted to avoid introducing
conflicts into Vincent's work on counterexamples. It turns out it's
completely orthogonal.
* data/README.md, data/skeletons/bison.m4, data/skeletons/c++.m4,
* data/skeletons/c.m4, data/skeletons/glr.c, data/skeletons/java.m4,
* data/skeletons/lalr1.d, data/skeletons/lalr1.java,
* data/skeletons/variant.hh, data/skeletons/yacc.c, src/conflicts.c,
* src/derives.c, src/gram.c, src/gram.h, src/output.c,
* src/parse-gram.c, src/parse-gram.y, src/print-xml.c, src/print.c,
* src/reader.c, src/symtab.c, src/symtab.h, tests/input.at,
* tests/types.at:
s/user_token_number/code/g.
Plus minor changes.
Currently we use the syncline to report errors about a symbol's
destructor/printer. This is not accurate (only file and line), and
this is incorrect: the file name is double quotes (a recent change,
needed to make sure we escape properly double quotes in it). And
worst of all: with --no-line, b4_syncline expands to nothing.
Rather, push the locations into the backend, and use them.
* src/muscle-tab.h, src/muscle-tab.c (muscle_location_grow): Make it
public.
* src/output.c (prepare_symbol_definitions): Use it to pubish the
location of the printer and destructor.
* data/skeletons/lalr1.java: Use complain_at instead of complain.
* tests/java.at (Java invalid directives): Adjust expectations.
* data/skeletons/bison.m4 (b4_symbol_action_location): Remove.
We should not use b4_syncline this way.
* maint:
maint: post-release administrivia
version 3.3.2
style: minor fixes
NEWS: named constructors are preferable to symbol_type ctors
gram: fix handling of nterms in actions when some are unused
style: rename local variable
CI: update the ICC serial number for travis-ci.org
