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