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cex: reformat the s/r and r/r reports

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In Bison we refer to "shift/reduce" conflicts, not "shift-reduce" (in
Bison 3.6.3 186 occurrences vs 15).  Enforce consistency on this.

Instead of "spending" a second line for each conflict to report the
lookaheads, put that on the same line as the type of conflict.  Also,
prefer "token" to "symbol".  Maybe we should even prefer "lookahead".
While at it, enable internationalization, with plurals where
appropriate.

As a consequence, instead of

    Shift-Reduce Conflict:
    6:    3 b: . %empty
    6:    6 d: c . A
    On Symbol: A

display

    Shift/reduce conflict on token A:
    6:    3 b: . %empty
    6:    6 d: c . A

* NEWS, doc/bison.texi, src/conflicts.c: Spell it "shift/reduce", not
"shift-reduce".
* src/counterexample.c (counterexample_report_shift_reduce)
(counterexample_report_reduce_reduce): Reformat and internationalize
output.
* tests/counterexample.at: Adjust expectations.
This commit is contained in:
Akim Demaille
2020-06-07 07:32:59 +02:00
parent 421662ec88
commit 1ccb4be02b
6 changed files with 61 additions and 81 deletions
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12
doc/bison.texi
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@@ -5618,13 +5618,13 @@ Specify the grammar's start symbol (@pxref{Start Decl}).
@end deffn
@deffn {Directive} %expect
Declare the expected number of shift-reduce conflicts, either overall or
Declare the expected number of shift/reduce conflicts, either overall or
for a given rule
(@pxref{Expect Decl}).
@end deffn
@deffn {Directive} %expect-rr
Declare the expected number of reduce-reduce conflicts, either overall or
Declare the expected number of reduce/reduce conflicts, either overall or
for a given rule
(@pxref{Expect Decl}).
@end deffn
@@ -9172,7 +9172,7 @@ Ambiguous grammars, since they have strings with more than one possible
sequence of reductions cannot have deterministic parsers in this sense.
The same is true of languages that require more than one symbol of
lookahead, since the parser lacks the information necessary to make a
decision at the point it must be made in a shift-reduce parser.
decision at the point it must be made in a shift/reduce parser.
Finally, as previously mentioned (@pxref{Mysterious Conflicts}),
there are languages where Bison's default choice of how to
summarize the input seen so far loses necessary information.
@@ -9182,9 +9182,9 @@ Bison generates a parser that uses a different algorithm, called
Generalized LR (or GLR). A Bison GLR
parser uses the same basic
algorithm for parsing as an ordinary Bison parser, but behaves
differently in cases where there is a shift-reduce conflict that has not
differently in cases where there is a shift/reduce conflict that has not
been resolved by precedence rules (@pxref{Precedence}) or a
reduce-reduce conflict. When a GLR parser encounters such a
reduce/reduce conflict. When a GLR parser encounters such a
situation, it
effectively @emph{splits} into a several parsers, one for each possible
shift or reduction. These parsers then proceed as usual, consuming
@@ -13885,7 +13885,7 @@ associated with any of the symbols in the current rule).
There was also the command @samp{%expect @var{n}} which said not to mention the
conflicts if there are @var{n} shift/reduce conflicts and no reduce/reduce
conflicts. In more recent versions of Bison, @code{%expect} and its
@code{%expect-rr} variant for reduce-reduce conflicts can be applied to
@code{%expect-rr} variant for reduce/reduce conflicts can be applied to
individual rules.
Later versions of Bison added many more new features.