Several features were flagged 'experimental' and waiting for user
feedback to 'stabilize', but i. AFAIK, no user ever reported anything
about them, ii. they'be been here long enough to prove they don't do
harm.
* doc/bison.texi: No longer experimental: default %printer and
%destructor (typed: <*> and untyped: <>), %define api.value.type union
and variant, Java parsers, XML output, LR family (lr, ielr, lalr),
semantic predicates (%?).
* tests/actions.at: Fix some log messages.
Prefer #error to fprintf: it fixes the invalid use of yyoutput in
%destructor, and it is an even stronger check: that the code is not
even emitted. The portability of #error is not really a problem here,
since the point is anyway to have the compilation fail.
Make sure that we cannot apply a type to the (main) action of a rule.
* src/reader.c (grammar_rule_check): Issue the warning.
* tests/input.at (Cannot type action): Check the warning.
* tests/input.at (_AT_UNUSED_VALUES_DECLARATIONS): Check
typed mid-rule actions.
* tests/report.at (Reports): Check that types of typed mid-rule
actions are reported.
* tests/actions.at (Typed mid-rule actions): Check that
the values of typed mid-rule actions are correct.
Prompted on Piotr Marcińczyk's message:
http://lists.gnu.org/archive/html/bug-bison/2017-06/msg00000.html.
See also http://lists.gnu.org/archive/html/bug-bison/2018-06/msg00001.html.
Because their type is unknown to Bison, the values of midrule actions are
not treated like the others: they don't have %printer and %destructor
support. In addition, in C++, (Bison) variants cannot work properly.
Typed midrule actions address these issues. Instead of:
exp: { $<ival>$ = 1; } { $<ival>$ = 2; } { $$ = $<ival>1 + $<ival>2; }
write:
exp: <ival>{ $$ = 1; } <ival>{ $$ = 2; } { $$ = $1 + $2; }
* src/scan-code.h, src/scan-code.l (code_props): Add a `type` field to
record the declared type of an action.
(code_props_rule_action_init): Add a type argument.
* src/parse-gram.y: Accept an optional type tag for actions.
* src/reader.h, src/reader.c (grammar_current_rule_action_append): Add
a type argument.
(grammar_midrule_action): When a mid-rule is typed, pass its type to
the defined dummy non terminal symbol.
grammar_current_rule_action_append was used in two different places:
for actual action (`{...}`), and for predicates (`%?{...}`). Let's
split this in two different functions.
* src/reader.h, src/reader.c (grammar_current_rule_predicate_append): New.
Extracted from...
(grammar_current_rule_action_append): here.
Remove arguments that don't apply.
Adjust dependencies.
Predicates with GLR are issued with synclines in the middle of C code:
case 2:
if (! (#line 6 "sempred.y" /* glr.c:816 */
new_syntax)) YYERROR;
#line 793 "sempred.tab.c" /* glr.c:816 */
break;
Reported by Rici Lake.
http://lists.gnu.org/archive/html/bug-bison/2018-05/msg00033.html
* data/c.m4 (b4_predicate_case): Be sure to start on column 0.
It would be nicer if b4_syncline could ensure this by itself
(that would avoid ugly code when synclines are disabled), but that's
way more work.
* tests/glr-regression.at (Predicates): Be a real end-to-end test.
This would have caught this error years ago...
