`look_ahead'. Discussed starting at
<http://lists.gnu.org/archive/html/bison-patches/2006-01/msg00049.html>
and then at
<http://lists.gnu.org/archive/html/bison-patches/2006-06/msg00017.html>.
* NEWS: For the next release, note the change to `--report'.
* TODO, doc/bison.1: Update English.
* doc/bison.texinfo: Update English.
(Understanding Your Parser, Bison Options): Document as
`--report=lookahead' rather than `--report=look-ahead'.
* src/conflicts.c: Update English in comments.
(lookahead_set): Rename from look_ahead_set.
(flush_reduce): Rename argument look_ahead_tokens to lookahead_tokens.
(resolve_sr_conflict): Rename local look_ahead_tokens to
lookahead_tokens, and update other uses.
(flush_shift, set_conflicts, conflicts_solve, count_sr_conflicts,
count_rr_conflicts, conflicts_free): Update uses.
* src/getargs.c (report_args): Move "lookahead" before alternate
spellings.
(report_types): Update uses.
(usage): For `--report' usage description, state `lookahead' spelling
rather than `look-ahead'.
* src/getargs.h (report.report_lookahead_tokens): Rename from
report_look_ahead_tokens.
* src/lalr.c: Update English in comments.
(compute_lookahead_tokens): Rename from compute_look_ahead_tokens.
(state_lookahead_tokens_count): Rename from
state_look_ahead_tokens_count.
Rename local n_look_ahead_tokens to n_lookahead_tokens.
(lookahead_tokens_print): Rename from look_ahead_tokens_print.
Rename local n_look_ahead_tokens to n_lookahead_tokens.
Update other uses.
Update English in output.
(add_lookback_edge, initialize_LA, lalr, lalr_free): Update uses.
* src/print.c: Update English in comments.
(lookahead_set): Rename from look_ahead_set.
(print_reduction): Rename argument lookahead_token from
look_ahead_token.
(print_core, state_default_rule, print_reductions, print_results):
Update uses.
* src/print_graph.c: Update English in comments.
(print_core): Update uses.
* src/state.c: Update English in comments.
(reductions_new): Update uses.
(state_rule_lookahead_tokens_print): Rename from
state_rule_look_ahead_tokens_print, and update other uses.
* src/state.h: Update English in comments.
(reductions.lookahead_tokens): Rename from look_ahead_tokens.
(state_rule_lookahead_tokens_print): Rename from
state_rule_look_ahead_tokens_print.
* src/tables.c: Update English in comments.
(conflict_row, action_row): Update uses.
* tests/glr-regression.at
(Incorrect lookahead during deterministic GLR,
Incorrect lookahead during nondeterministic GLR): Rename
print_look_ahead to print_lookahead.
* tests/torture.at: Update English in comments.
(AT_DATA_LOOKAHEAD_TOKENS_GRAMMAR): Rename from
AT_DATA_LOOK_AHEAD_TOKENS_GRAMMAR.
(Many lookahead tokens): Update uses.
* data/glr.c: Update English in comments.
* lalr1.cc: Likewise.
* yacc.c: Likewise.
* src/conflicts.h: Likewise.
* src/lalr.h: Likewise.
* src/main.c: Likewise.
* src/output.c: Likewise.
* src/parse-gram.c: Likewise.
* src/tables.h: Likewise.
* tests/calc.at: Likewise.
release number, and use that as a signal to automatically print the
ChangeLog's CVS Id keyword from --version. Discussed starting at
<http://lists.gnu.org/archive/html/bison-patches/2006-05/msg00028.html>.
* ChangeLog: Add Id header.
* configure.ac (AC_INIT): Append `+' to `2.3'.
* src/.cvsignore: Add revision.c.
* src/Makefile.am (bison_SOURCES): Add revision.c and revision.h.
(BUILT_SOURCES): Add revision.c.
(revision.c): New target rule. This file defines a new global variable
named revision. It initializes it with either the Id from ChangeLog
or, if VERSION doesn't contain `+', with the empty string.
* src/getargs.c (version): Print the value of revision.
* src/revision.h: Extern revision.
to make sure that YYID will never be unused. This fixes a 'make
maintainer-check' failure caused by the recent changes to the 'Trivial
grammars' test case, which caused g++ 4.1.0 to complain that YYID was
not used.
* data/glr.c (yyparse): Wrap yyparse's return inside YYID just in case.
state before an empty RHS is always resolved here. Only the location
of that state is guaranteed to be resolved, and that's enough. This
fixes the remaining bug reported by Derek M. Jones in
<http://lists.gnu.org/archive/html/bug-bison/2006-05/msg00027.html>.
* tests/glr-regression.at (Uninitialized location when reporting
ambiguity): Test the above case.
Also, the embedded comments in this test case claim it checks the case
of an empty RHS that has inherited the initial location. However, the
corresponding LHS was already resolved, so yyresolveLocations didn't
actually have reason to modify it. Fix this by forcing
nondeterministic operation at the beginning of the parse.
preceding the RHS. This fixes the segmentation fault reported by Derek
M. Jones in
<http://lists.gnu.org/archive/html/help-bison/2006-05/msg00035.html>.
(yyreportTree, yypdumpstack): Subtract 1 from yyrule before printing
to the user. Reported for yyreportTree by Derek M. Jones later in the
same thread.
* THANKS: Add Derek M. Jones.
Update my email address.
Fix typo in Steve Murphy's name.
ambiguity): New test case.
* data/glr.c (yyresolveLocations): New function, which uses
YYLLOC_DEFAULT.
(yyresolveValue): Invoke yyresolveLocations before reporting an
ambiguity.
* doc/bison.texinfo (Default Action for Locations): Note
YYLLOC_DEFAULT's usage for ambiguity locations.
(GLR Semantic Actions): Cross-reference those notes.
ambiguity): Remove unnecessary union and type declarations.
(Leaked lookahead after nondeterministic parse syntax error): New test
case.
* data/glr.c (yyparse): Check for zero stacks remaining before
attempting to shift the lookahead so that you don't lose it.
* tests/glr-regression.at (Leaked semantic values when reporting
ambiguity): New test case.
* data/glr.c (yyreportAmbiguity): Invoke yyyerror directly and return
yyabort rather than invoking yyFail, which invokes longjmp. Remove the
now unnecessary yystackp parameter.
(yyresolveValue): Return yyreportAmbiguity's result. Now the necessary
destructors can be called.
* tests/glr-regression.at: Don't invoke bison with `-t' unnecessarily
in existing testcases.
parser, and clean up related code a bit.
* tests/glr-regression.at (Leaked merged semantic value if user action
cuts parse) Rename to...
(Leaked semantic values if user action cuts parse) ... this. Add check
for leaked parent RHS values.
* data/glr.c (yydestroyGLRState): In debugging output, distinguish
between an unresolved state (non-empty chain of semantic options) and
an incomplete one (signaled by an empty chain).
(yyresolveStates): Document the interface. Move all manipulation of an
successfully or unsuccessfully resolved yyGLRState to...
(yyresolveValue): ... here so that yyresolveValue always leaves a
yyGLRState with consistent data and thus is easier to understand.
Remove the yyvalp and yylocp parameters since they are always just
taken from the yys parameter. When reporting a discarded merged value
in debugging output, note that it is incompletely merged. Document the
interface.
(yyresolveAction): If resolving any of the RHS states fails, destroy
them all rather than leaking them. Thus, as long as user actions are
written to clean up the RHS correctly, yyresolveAction always cleans up
the RHS of a semantic option. Document the interface.
influence the parse by changing yychar. To make this easier to fix and
to make glr.c easier to evolve in general, don't maintain yytoken in
parallel with yychar; just compute yytoken when needed.
* tests/glr-regression.at (Incorrect lookahead during deterministic
GLR): Check that setting yychar in a user action has the intended
effect.
* data/glr.c (yyGLRStack): Remove yytokenp member.
(yyclearin): Don't set *yytokenp.
(yyprocessOneStack, yyreportSyntaxError, yyrecoverSyntaxError): Examine
yychar rather than *yytokenp to determine the current lookahead.
Compute yytoken locally when needed.
(yyparse): Likewise. Remove the local yytoken that yytokenp used to
point to.
* doc/bison.texinfo (Bison Options): Remove stray sentence fragment
after `--report' documentation.
yylookaheadNeeds. All uses updated.
(yysplitStack): Rename local yynewLookaheadStatuses to
yynewLookaheadNeeds.
* data/glr-regression.at (Incorrect lookahead during nondeterministic
GLR): In comments, change `lookahead status' to `lookahead need'.
(GLR Semantic Actions): New subsection discussing special
considerations because GLR semantic actions might be deferred.
(Actions): Mention look-ahead usage of yylval.
(Actions and Locations): Mention look-ahead usage of yylloc.
(Special Features for Use in Actions): Add YYEOF entry and mention it
in the yychar entry.
In the yychar entry, remove mention of the local yychar case (pure
parser) since this is irrelevant information when writing semantic
actions and since it's already discussed in `Bison Symbols' where
yychar is otherwise described as an external variable.
In the yychar entry, don't call it the `current' look-ahead since it
isn't when semantic actions are deferred.
In the yychar and yyclearin entries, add note about deferred semantic
actions.
Add yylloc and yylval entries discussing look-ahead usage.
(Look-Ahead Tokens): When discussing yychar, don't call it the
`current' look-ahead, and do mention yylval and yylloc.
(Error Recovery): Cross-reference `Action Features' when mentioning
yyclearin.
(Bison Symbols): In the yychar entry, don't call it the `current'
look-ahead.
In the yylloc and yylval entries, mention look-ahead usage.
use during nondeterministic operation to track which stacks have
actually needed the current lookahead.
(yyinitStateSet, yyfreeStateSet, yyremoveDeletes, yysplitStack):
Allocate, deallocate, resize, and otherwise shuffle space for
yylookaheadStatuses in parallel with yystates member of yyGLRStateSet.
(yysplitStack, yyprocessOneStack, yyparse): Set lookahead status
appropriately during nondeterministic operation.
(yySemanticOption): Add int yyrawchar, YYSTYPE yyval, and YYLTYPE yyloc
members to store the current lookahead to be used by the deferred
user action.
(yyaddDeferredAction): Add size_t yyk parameter specifying the stack
from which the RHS is taken. Set the lookahead members of the new
yySemanticOption according to the lookahead status for stack yyk.
(yyglrShiftDefer, yyglrReduce): Pass yyk parameter on to
yyaddDeferredAction.
(yyresolveAction): Set yychar, yylval, and yylloc to the lookahead
members of yySemanticOption before invoking yyuserAction, and then set
them back to their current values afterward.
(yyparse): Set yychar = YYEMPTY where yytoken = YYEMPTY.
(yyreportAmbiguity): Add /*ARGSUSED*/ to pacify lint.
* tests/glr-regression.at: Remove `.' from the ends of recent test case
titles for consistency.
(Leaked merged semantic value if user action cuts parse): In order to
suppress lint warnings, use arguments in merge function, and assign
char value < 128 in main.
(Incorrect lookahead during deterministic GLR): New test case.
(Incorrect lookahead during nondeterministic GLR): New test case.
!yyvaluep as signal that no semantic value is available to print.
* data/glr.c (yydestroyGLRState): If state is not resolved, don't try
to print a semantic value.
least one user action succeeds but a later one cuts the parse, then
destroy the semantic value before returning rather than leaking it.
(yyresolveStates): If a user action cuts the parse and thus
yyresolveValue fails, ignore the (unset) semantic value rather than
corrupting the yyGLRState, and empty the semantic options list since
the user actions should have called all necessary destructors.
Simplify code with YYCHK.
* tests/glr-regression.at (Corrupted semantic options if user action
cuts parse): New test case.
(Undesirable destructors if user action cuts parse): New test case.
Before applying any of this patch, this test case never actually failed
for me... but only because the corrupted semantic options usually
masked this bug.
(Leaked merged semantic value if user action cuts parse): New test
case.
Joel E. Denny