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author | Akim Demaille <akim.demaille@gmail.com> | 2020-03-02 06:08:08 +0100 |
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committer | Akim Demaille <akim.demaille@gmail.com> | 2020-03-05 07:13:23 +0100 |
commit | 744171ddbff0e398c81c0ced966c9a483ddf51a9 (patch) | |
tree | 38e289757e7e4033666696148fff7c73c4ae7650 /TODO | |
parent | 4fd3282dd7823f8c7870622f2f73f6e6af60f6b7 (diff) | |
download | bison-744171ddbff0e398c81c0ced966c9a483ddf51a9.tar.gz |
yacc.c: push: initialize the pstate variables in pstate_new
Currently pstate_new does not set up its variables, this task is left
to yypush_parse. This was probably to share more code with usual pull
parsers, where these (local) variables are indeed initialized by
yyparse.
But as a consequence yyexpected_tokens crashes at the very beginning
of the parse, since, for instance, the stacks are not even set up.
See https://lists.gnu.org/r/bison-patches/2020-03/msg00001.html.
The fix could have very simple, but the documentation actually makes
it very clear that we can reuse a pstate for several parses:
After yypush_parse returns a status other than YYPUSH_MORE, the
parser instance yyps may be reused for a new parse.
so we need to restore the parser to its pristine state so that (i) it
is ready to run the next parse, (ii) it properly supports
yyexpected_tokens for the next run.
* data/skeletons/yacc.c (b4_initialize_parser_state_variables): New,
extracted from the top of yyparse/yypush_parse.
(yypstate_clear): New.
(yypstate_new): Use it when push parsers are enabled.
Define after the yyps macros so that we can use the same code as the
regular pull parsers.
(yyparse): Use it when push parsers are _not_ enabled.
* examples/c/bistromathic/bistromathic.test: Check the completion on
the beginning of the line.
Diffstat (limited to 'TODO')
-rw-r--r-- | TODO | 3 |
1 files changed, 3 insertions, 0 deletions
@@ -95,6 +95,9 @@ See also the item "$undefined" below. Consider deprecating impure push parsers. They add a lot of complexity, for a bad feature. +It's not clear to me that yyerror_range really needs to be in pstate, +instead of just being a local variable. + * Bison 3.7 ** Unit rules / Injection rules (Akim Demaille) Maybe we could expand unit rules (or "injections", see |