I'm quite pleased to see that the tricky case of glr.c was already
prepared by the changes to support syntax_error exceptions. Better
yet, it is actually syntax_error that becomes a special case of the
general pattern: make yytoken be YYERRCODE.
* data/skeletons/glr.c (YYFAULTYTOK): Remove the now useless (Basil)
Faulty token.
Instead, use the error token.
* data/skeletons/lalr1.d, data/skeletons/lalr1.java: When computing
the action, first check the case of the error token.
* tests/calc.at: Check cases for the error token symbols before and
after it.
* data/skeletons/yacc.c (yyparse): When the scanner returns YYERRCODE,
go directly to error recovery (yyerrlab1).
However, don't keep the error token as lookahead, that token is too
special.
* data/skeletons/lalr1.cc: Likewise.
* examples/c/bistromathic/parse.y (yylex): Use that feature to report
nicely invalid characters.
* examples/c/bistromathic/bistromathic.test: Check that.
* examples/test: Neutralize gratuitous differences such as rule
position.
* tests/calc.at: Check that case in C only.
The other case seem to be working, but that's an illusion that the
next commit will address (in fact, they can enter endless loops, and
report the error several times anyway).
On macOS, wc -l always prepends the result with a tab, even when fed
by stdin. But anyway, we should have used `grep -c -v`, which appears
to be portable according to Autoconf's "Limitations of Usual Tools"
section.
Reported by Denis Excoffier.
https://lists.gnu.org/r/bug-bison/2020-04/msg00009.html
* tests/calc.at (_AT_CHECK_CALC): Use grep's -c instead.
* data/skeletons/lalr1.cc: added support here
* tests/calc.at: added test cases
* tests/local.at: added yyreport_syntax_error implementation
for C++ test cases
This revealed a number of things I had not realized:
- the Java location tracking was aliasing the same pair of positions
for all the symbols (see previous commit).
- in impure parsers, it's quite easy to use incorrect locations for
diagnostics, since yyerror uses yylloc, which is the location of the
lookahead, not that of the current lhs. So we need something like
{
YYLTYPE old_yylloc = yylloc;
yylloc = @$;
yyerror (]AT_PARAM_IF([result, count, nerrs, ])[buf);
yylloc = old_yylloc;
}
Maybe we should do that little yylloc dance in the skeleton instead
of leaving it to the user? It might be costly... But that's only
for users of the impure parsers, which are asking for trouble
anyway.
- in glr.cc invoking yyerror is somewhat cumbersome: the C++ interface
is not available as we are in yyparse (which in C), and yyerror is
used by glr.cc itself to bind it to the user's parser::error. If we
call yyerror, we need:
yyerror (]AT_LOCATION_IF([[&@$, ]])[yyparser, ]AT_PARAM_IF([result, count, nerrs, ])[msg);
However calling yy::parser::error is easier, once we know that the
current parser object is available as 'yyparser'. Which also saves
us from having to pass the parse-params ourselves:
yyparser.error (]AT_LOCATION_IF([[@$, ]])[msg);
* tests/calc.at: Invoke yyerror by hand, instead of using fprintf etc.
Adjust expectations.
In Java there is no need for N_ and yytranslate_. So instead of
hard-coding the use of N_ in the table of the symbol names, rely on
b4_symbol_translate.
* src/output.c (prepare_symbol_names): Use b4_symbol_translate instead
of N_.
* data/skeletons/c.m4 (b4_symbol_translate): New.
* data/skeletons/lalr1.java (yysymbolName): New.
Use it.
* examples/java/calc/Calc.y: Use parse.error=detailed.
* tests/calc.at: Check parse.error=detailed.
Unfortunately in the Java skeleton the user cannot override the way
locations are displayed, and locations don't know the structure of the
positions. So they cannot implement the tricks used in the C/C++
skeletons to display "1.1" instead of "1.1-1.2".
* tests/local.at (Java): Add support for column tracking in the
locations, as we did in examples/java/calc.
* tests/calc.at: Use AT_CALC_YYLEX.
The C, C++ and D skeletons used to show the stack right after popping
the stack during the reduction. Now that the stack is printed after
reaching a new state, that has become useless:
Entering state 1
Stack now 0 1
Reducing stack by rule 5 (line 83):
$1 = token "number" (1)
-> $$ = nterm exp (1)
Stack now 0
Entering state 8
Stack now 0 8
Remove the "Stack now 0" line.
* data/skeletons/lalr1.cc, data/skeletons/lalr1.d,
* data/skeletons/lalr1.java, data/skeletons/yacc.c:
Here.
Currently, if we have long rules and series of shift, we stack states
without showing stack. Let's be more incremental, and do how the Java
skeleton does.
* data/skeletons/lalr1.cc, data/skeletons/lalr1.d,
* data/skeletons/yacc.c:
Here.
Adjust test cases.
* tests/torture.at (AT_DATA_STACK_TORTURE): Disable stack traces: this
test produces a very large stack, and showing the stack each time we
shift a token goes quadatric.
The Java skeleton displays
Reading a token:
Next token is token "number" (1)
while the other display
Reading a token: Next token is token "number" (1)
When generating logs in the scanner, the first part is separated from
the second, and the end of the scanner logs have the second part
pasted in. So let's propagate the Java way, but with the colon.
* data/skeletons/glr.c, data/skeletons/lalr1.cc, data/skeletons/lalr1.d,
* data/skeletons/lalr1.java, data/skeletons/yacc.c: Do it.
Adjust test cases and doc.
* tests/local.at (AT_LANG_MATCH): New.
(AT_YYERROR_DECLARE(java), AT_YYERROR_DECLARE_EXTERN(java)): New.
* tests/calc.at: The grammar file for Java is quite different for the
others, and continuing to assemble it from pieces makes the grammar
file hard to understand. Let's also dispatch on the language to
assemble it, and isolate Java from the others.
Most of this comes from java.at.
When building the test cases, emitting code in the epilogue is very
constraining. Let's make it simpler thanks to %code epilogue.
However, I don't want to document this: it is bad style to use it (we
should avoid having too many ways to write the same thing,
TI!MTOWTDI), just put your code in the true epilogue section.
* data/skeletons/glr.c, data/skeletons/lalr1.d, data/skeletons/lalr1.java,
* data/skeletons/yacc.c: Implement support for %code epilogue.
Remove useless comments.
* tests/calc.at, tests/java.at: Simplify.
Some users would like to avoid having to "parse" the *.y file to find
the strings to translate. Let's issue the translatable tokens with N_
to allow "parsing" the generated parsers instead.
See
https://lists.gnu.org/archive/html/bison-patches/2019-01/msg00015.html
* src/output.c (prepare_symbol_names): Issue symbol_names with N_()
markup.
"detailed" error messages are almost like "verbose", except that we
don't double escape them, they don't get inner quotes, we don't use
yytnamerr, and we hide the table.
"custom" is exposed with the "detailed" tokens, not the "verbose"
ones: they are not double-quoted.
Because there's a risk that some people use yytname even without
"verbose", let's keep yytname (instead of yys_name) in "simple"
parse.error.
* src/output.c (prepare_symbol_names): Be ready to output symbol names
unquoted.
(prepare_symbol_names): Output both the old tname table, and the new
symbol_names one.
* data/skeletons/bison.m4: Accept 'detailed'.
* data/skeletons/yacc.c: When parse.error is 'detailed', don't emit
yytname and yytnamerr, just yysymbol_name with the table inside.
* tests/calc.at: Adjust.
Enhance the calculator tests: show that passing arguments to yyerror
works.
* tests/calc.at: Add a new parse-param, nerrs, which counts the number
of syntax errors in a run.
* tests/local.at: Adjust to handle the new 'nerrs' argument, when
present.
The custom error reporting function show sees the user's additional
arguments. Let's experiment with passing them as arguments to
yyreport_syntax_error, but maybe storing them in the context would be
a bettter alternative.
* data/skeletons/yacc.c (yyreport_syntax_error): Handle the
parse-params.
* tests/calc.at, tests/local.at: Adjust.
Currently the parse-params are tested in calc.at by checking that the
global variable and the parse-params have the same value. But it does
not check that value, that could remain being 0 just as well.
* tests/calc.at: Don't define the params when they are not used.
Check the final value of result and count.
Also, do count the number of line of logs.
We use a different format to check parse.error custom. Compute the
"verbose" one from it instead of forcing the test author to provide
the various formats of expected error messages.
* tests/calc.at (_AT_CHECK_CALC_ERROR): Handle this transformation
when needed.
Simplify callers.
* tests/local.at (AT_ERROR_CUSTOM_IF, AT_ERROR_VERBOSE_IF)
(AT_ERROR_SIMPLE_IF): New.
(AT_YYERROR_DEFINE(c)): Generate yyreport_syntax_error.
* tests/calc.at (_AT_CHECK_CALC_ERROR): Accept custom error messages
as additional test case.
Use it.
Add a new test case for %define parse.error custom.
Let's make a difference between places where Perl is required for the
test (AT_PERL_REQUIRE), and the places where it's used to run the
test, but it's not not to run the test (AT_PERL_CHECK).
* tests/local.at (AT_REQUIRE): New.
(AT_PERL_CHECK, AT_PERL_REQUIRE): New.
Use them where appropriate.
* tests/local.mk ($(TESTSUITE)): Beware not to start the line with
'-pi' if Perl is empty, as Make understands this as "it's ok to fail".
Which it is not.
My previous tests (with ./configure PERL=false) have been fooled by
configure, that managed to find perl anyway. This time, I ran this on
a Fedora in Docker, without Perl.
* tests/calc.at, tests/diagnostics.at, tests/headers.at,
* tests/input.at, tests/local.at, tests/named-refs.at,
* tests/output.at, tests/regression.at, tests/skeletons.at,
* tests/synclines.at, tests/torture.at: Don't require Perl.
* configure.ac (DCFLAGS): Pass -g.
* data/skeletons/d.m4 (b4_locations_if): Remove, let bison.m4's one do
its job.
* data/skeletons/lalr1.d (position): Leave filename empty by default.
(position::toString): Don't print empty file names.
(location::this): New ctor.
(location::toString): Match the implementations of C/C++.
(yy_semantic_null): Leave undefined, the previous implementation does
not compile.
* tests/calc.at: Improve the implementation for D.
Enable more checks, in particular using locations.
* tests/local.at (AT_YYERROR_DEFINE(d)): Fix its implementation.
* data/skeletons/lalr1.java: Use more conventional function names for
Java.
Prefer < and <= to => and >.
Use the same approach for m4 quotation as in the other skeletons.
Fix indentation issues.
* tests/calc.at, tests/java.at, tests/javapush.at: Fix quotation style.
(main): Use 'args', not 'argv', the former seems more conventional and
is used elsewhere in Bison.
Prefer character literals to integers to denote characters.
* examples/java/Calc.y: Likewise.
Reported by Balázs Scheidler.
* data/skeletons/c.m4 (b4_location_type_define): Use api.location.type
if defined.
* doc/bison.texi: Document it.
* tests/local.at (AT_C_IF, AT_LANG_CASE): New.
Support Span in C.
* tests/calc.at (Span): Convert it to be usable in C and C++.
Check api.location.type with yacc.c and glr.c.
