Le 30 sept. 2013 à 11:01, Markus Elfring <markus.elfr...@web.de> a écrit :
> Hello, > > I try to develop a small grammar. Unfortunately, I stumble on error messages > like the following during the build process on my openSUSE system. Hi! > ... > Building parser with bison 3.0 > parser.ypp:68.18-20: warning: type clash on default action: <char> != <> > [-Wother] > value_character: '0' > ^^^ > parser.ypp:69.21-23: warning: type clash on default action: <char> != <> > [-Wother] > | '1' > ^^^ The warning is telling you that value_character is typed, expecting $$ to have a value, but '0' and '1' have no value associated. You should provide them with a value. > ... > > > I guess that this happens because of this setting for better C++ support. > %define api.value.type variant > http://www.gnu.org/software/bison/manual/bison.html#C_002b_002b-Variants No, this is unrelated. > I have found the following comment in a source file. > http://git.savannah.gnu.org/cgit/bison.git/tree/data/lalr1.cc?id=cc8962bdde81b04aa728aef21e53b4a08a0debfe#n818 > /* Variants are always initialized to an empty instance of the > correct type. The default $$=$1 action is NOT applied when using > variants. */ > Now I am interested in further solutions. > - Can the used variant template class be extended? You are not expected to extent it, just used it. See the corresponding section. > - Is a conversion possible without the specification of a specific data type > in > a directive like "%token"? I'm not sure to understand what you mean. If '0' is expected to have a value, then you should declare it %token <character> '0' '1' > - The character list can become long in my use case here. That's weird. Maybe should have a single token type 'character', and store the character value in its semantic value. > I would like to avoid > the repetition of similar actions behind them. It would be more "convenient" > to > choose a different default action for selected rules, wouldn't it? One usually does not need that, as this kind of job is typically left to the scanner/lexer, not to the parser. _______________________________________________ help-bison@gnu.org https://lists.gnu.org/mailman/listinfo/help-bison
