* examples/d/calc/calc.y (start, end): Replace by this...
(location): new member variable in the Lexer class.
Use it.
* tests/calc.at: Use the defined location variable.
This avoids heap allocation and gives minimal costs for the
creation and destruction of the YYParser.Symbol struct if
the location tracking is active.
Suggested by H. S. Teoh.
* data/skeletons/lalr1.d: Here.
* doc/bison.texi: Document it.
* examples/d/calc/calc.y: Adjust.
* tests/calc.at: Test it.
The complete symbol approach was deemed to be the right approach for Dlang.
Now, the user can return from yylex() an instance of YYParser.Symbol structure,
which binds together the TokenKind, the semantic value and the location. Before,
the last two were reported separately to the parser.
Only the user API is changed, Bisons's internal structure is kept the same.
* data/skeletons/d.m4 (struct YYParser.Symbol): New.
* data/skeletons/lalr1.d: Change the return value.
* doc/bison.texi: Document it.
* examples/d/calc/calc.y, examples/d/simple/calc.y: Demonstrate it.
* tests/calc.at, tests/scanner.at: Test it.
Parser.Context class returns a const YYLocation, so Lexer's method
yyerror() needs to receive the location as a const parameter.
Internal error reporting flow is changed to be similar to that of
the other skeletons. Before, case YYERRLAB was calling yyerror()
with the result of yysyntax_error() as the string parameter. As the
custom error message lets the user decide if they want to use
yyerror() or not, this flow needed to be changed. Now, case YYERRLAB
calls yyreportSyntaxError(), that builds the error message using
yysyntaxErrorArguments(). Then yyreportSyntaxError() passes the
error message to the user defined syntax_error() in case of a custom
message, or to yyerror() otherwise.
In the tests in tests/calc.at, the order of the tokens needs to be
changed in order of precedence, so that the D program outputs the
expected tokens in the same order as the other parsers.
* data/skeletons/lalr1.d: Add the custom error message feature.
* doc/bison.texi: Document it.
* examples/d/calc/calc.y: Adjust.
* tests/calc.at, tests/local.at: Test it.
In D's case, yyerrok() is a private method of the Parser class.
It can be called directly as `yyerrok()` from the grammar rules section.
* data/skeletons/lalr1.d: Add yyerrok().
* examples/d/calc/calc.y, examples/d/simple/calc.y: Demonstrate yyerrok().
* tests/calc.at: Update D tests to use yyerrok().
* data/skeletons/lalr1.d: Change the return value.
* examples/d/calc/calc.y, examples/d/simple/calc.y: Adjust.
* tests/scanner.at: Adjust.
* tests/calc.at (_AT_DATA_CALC_Y(d)): New, extracted from...
(_AT_DATA_CALC_Y(c)): here.
The two grammars have been sufficiently different to be separated.
Still trying to be them together results in a maintenance burden. For
the same reason, instead of specifying the results for D and for the
rest, compute the expected results with D from the regular case.
