Address compiler warnings such as
warning: declaration of 'yyla' shadows a member of 'yy::parser::context' [-Wshadow]
* data/skeletons/lalr1.cc (context): Don't use the same names for
variables and members.
Use foo_ for private members, as in parser.
Also, use the + trick in array accesses to please ICC and provide it
with an int.
Since Bison 2.7, output was indented four spaces for explanatory
statements. For example:
input.y:2.7-13: error: %type redeclaration for exp
input.y:1.7-11: previous declaration
Since the introduction of caret-diagnostics, it became less clear.
Remove the indentation and display submessages as in GCC:
input.y:2.7-13: error: %type redeclaration for exp
2 | %type <float> exp
| ^~~~~~~
input.y:1.7-11: note: previous declaration
1 | %type <int> exp
| ^~~~~
* src/complain.h (SUB_INDENT): Remove.
(warnings): Add "note" to the enum.
* src/complain.h, src/complain.c (complain_indent): Replace by...
(subcomplain): this.
Adjust all dependencies.
* tests/actions.at, tests/diagnostics.at, tests/glr-regression.at,
* tests/input.at, tests/named-refs.at, tests/regression.at:
Adjust expectations.
The error format should be translated, but contrary to the case of
C/C++, we cannot just depend on macros to adapt on the
presence/absence of '_'. Let's consider that the message format is to
be translated iff there are some internationalized tokens.
* src/output.c (prepare_symbol_names): Define b4_has_translations.
* data/skeletons/java.m4 (b4_trans): New.
* data/skeletons/lalr1.java: Use it to emit translatable or not the
format string.
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.
We used to display the unexpected token first:
$ bison foo.y
foo.y:1.8-13: error: syntax error, unexpected %token, expecting character literal or identifier or <tag>
1 | %token %token
| ^~~~~~
GCC uses a different format:
$ gcc-mp-9 foo.c
foo.c:1:5: error: expected identifier or '(' before ')' token
1 | int()()()
| ^
and so does Clang:
$ clang-mp-9.0 foo.c
foo.c:1:5: error: expected identifier or '('
int()()()
^
1 error generated.
They display the unexpected token last (or not at all). Also, they
don't waste width with "syntax error". Let's try that. It gives, for
the same example as above:
$ bison foo.y
foo.y:1.8-13: error: expected character literal or identifier or <tag> before %token
1 | %token %token
| ^~~~~~
* src/complain.h, src/complain.c (syntax_error): New.
* src/parse-gram.y (yyreport_syntax_error): Use it.
As a test case, support translations in Bison itself.
* src/parse-gram.y: Mark the translatable tokens.
While at it, use clearer names.
* tests/input.at: Adjust expectations.
Don't force callers of location_caret to have to deal with flags that
disable it.
* src/location.h, src/location.c (location_caret)
(location_caret_suggestion): Early return if disabled.
* src/complain.c: 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.
In addition to
%token NUM "number"
accept
%token NUM _("number")
in which case the token will be translated in error messages.
Do not use _() in the output if there are no translatable tokens.
* src/symtab.h, src/symtab.c (symbol): Add a 'translatable' member.
* src/parse-gram.y (TSTRING): New token.
(string_as_id.opt): Replace with...
(alias): this.
Use it.
* src/scan-gram.l (SC_ESCAPED_TSTRING): New start conditions, to match
TSTRINGs.
* src/output.c (prepare_symbols): Define b4_translatable if there are
translatable strings.
* data/skeletons/glr.c, data/skeletons/lalr1.cc,
* data/skeletons/yacc.c (yytnamerr): Receive b4_translatable, and use it.
* src/output.c (escape_trigraphs, xescape_trigraphs): New.
(prepare_symbol_names): Use it.
* tests/regression.at: Check the handling of trigraphs with
parse.error = detailed.
"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.
Only parse.error verbose and simple will get the original yytname: the
other options will rely on a different table. So let's move on top of
the yysymbol_name function.
* data/skeletons/c.m4 (yy_symbol_print): Use yysymbol_name.
* data/skeletons/glr.c (yytokenName): Rename as...
(yysymbol_name): this.
The change of naming scheme is unfortunate, but it's definitely glr.c
which is "wrong".
String literals, which allow for better error messages, are (too)
liberally accepted by Bison, which might result in silent errors. For
instance
%type <exVal> cond "condition"
does not define “condition” as a string alias to 'cond' (nonterminal
symbols do not have string aliases). It is rather equivalent to
%nterm <exVal> cond
%token <exVal> "condition"
i.e., it gives the type 'exVal' to the "condition" token, which was
clearly not the intention.
Introduce -Wdangling-alias to catch this.
* src/complain.h, src/complain.c: Add support for -Wdangling-alias.
(argmatch_warning_args): Sort.
* src/symtab.c (symbol_check_defined): Complain about dangling
aliases.
* doc/bison.texi: Document it.
* tests/input.at (Dangling aliases): New test.
On
%token TOKEN1
%type <ival> TOKEN1 TOKEN2 't'
%token TOKEN2
%%
expr:
bison -Wyacc gives
input.y:2.15-20: warning: POSIX yacc reserves %type to nonterminals [-Wyacc]
2 | %type <ival> TOKEN1 TOKEN2 't'
| ^~~~~~
input.y:2.29-31: warning: POSIX yacc reserves %type to nonterminals [-Wyacc]
2 | %type <ival> TOKEN1 TOKEN2 't'
| ^~~
input.y:2.22-27: warning: POSIX yacc reserves %type to nonterminals [-Wyacc]
2 | %type <ival> TOKEN1 TOKEN2 't'
| ^~~~~~
The messages appear to be out of order, but they are emitted when the
error is found.
* src/symtab.h (symbol_class): Add pct_type_sym, used to denote
symbols appearing in %type.
* src/symtab.c (complain_pct_type_on_token): New.
(symbol_class_set): Check that %type is not applied to tokens.
(symbol_check_defined): pct_type_sym also means undefined.
* src/parse-gram.y (symbol_decl.1): Set the class to pct_type_sym.
* src/reader.c (grammar_current_rule_begin): pct_type_sym also means
undefined.
* tests/input.at (Yacc's %type): New.
* src/gram.c (grammar_dump): Print terminals likewise non terminals.
* tests/sets.at (Reduced Grammar): Update test case to catch up the
change and add a test case where prec and assoc are used.
We have too many global variables, adding structure would help. For a
start, let's hide some of the variables closer to their usage.
* src/getargs.c, src/files.h (current_file): Move to...
* src/scan-gram.c: here.
* src/scan-gram.h (gram_in, gram__flex_debug): Remove, make them
private to the scanner.
* src/reader.h, src/reader.c (reader): Take a grammar file as argument.
Move the handling of scanner variables to...
* src/scan-gram.l (gram_scanner_open, gram_scanner_close): here.
(gram_scanner_initialize): Remove, replaced by gram_scanner_open.
* src/main.c: Adjust.
* src/parse-gram (%initial-action): here.
(handle_skeleton): Don't depend on the current file name to look for
"local" skeletons (subject to changes coming from "#lines"): depend
only on the initial file name, the one given on the command line.
Currently there are two globals denoting the input file: grammar_file
is the one from the command line, and current_file which might change
because of #line. Use only the former.
* src/complain.c (error_message): here.
* tests/diagnostics.at: Adjust.
