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* src/lalr.c (state_lookahead_tokens_count): For code readability,

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move the check for disabled transitions to an aver since conflict
resolution hasn't happened yet.

* src/lalr.c (state_lookahead_tokens_count): Remove the check that
labels a state as inconsistent just because it has error transitions.
The original form of this check appeared in revision 1.1 of lalr.c,
which was committed on 1991-12-21.  Now (at least), changing the
consistency label on such a state appears to have no useful effect in
any of the places it is examined, which I enumerate below.  The key
point to understanding each item in this enumeration is that a state
with an error transition is labelled consistent in the first place only
if it has no rules, so the check cannot matter for states that have
rules.  (1) Labelling a state as inconsistent will cause set_conflicts
to try to identify its conflicts, and a state must have *rules* to have
conflicts.  (2) Labelling a state as inconsistent will affect how
action_row sets the default *rule* for the state.  (3) Labelling a
state as inconsistent will cause build_relations to add lookback edges
to *rules* in that state.
* src/state.h (struct state): Word the comment for member consistent
more carefully.
This commit is contained in:
Joel E. Denny
2007-05-28 04:14:18 +00:00
parent 14462c2b1b
commit 2a6b783def
3 changed files with 32 additions and 12 deletions
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24
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@@ -1,3 +1,27 @@
2007-05-28 Joel E. Denny <jdenny@ces.clemson.edu>
* src/lalr.c (state_lookahead_tokens_count): For code readability,
move the check for disabled transitions to an aver since conflict
resolution hasn't happened yet.
* src/lalr.c (state_lookahead_tokens_count): Remove the check that
labels a state as inconsistent just because it has error transitions.
The original form of this check appeared in revision 1.1 of lalr.c,
which was committed on 1991-12-21. Now (at least), changing the
consistency label on such a state appears to have no useful effect in
any of the places it is examined, which I enumerate below. The key
point to understanding each item in this enumeration is that a state
with an error transition is labelled consistent in the first place only
if it has no rules, so the check cannot matter for states that have
rules. (1) Labelling a state as inconsistent will cause set_conflicts
to try to identify its conflicts, and a state must have *rules* to have
conflicts. (2) Labelling a state as inconsistent will affect how
action_row sets the default *rule* for the state. (3) Labelling a
state as inconsistent will cause build_relations to add lookback edges
to *rules* in that state.
* src/state.h (struct state): Word the comment for member consistent
more carefully.
2007-05-27 Joel E. Denny <jdenny@ces.clemson.edu>
Don't depend on C99 features.