Thanks for the quick reply! Hugs code hepled. (That is weird how they never use bison precedence annotations and just use multiple levels of non-terminals.)
-- Regards, Petr. 2010/3/23 Hans Aberg <haber...@telia.com> > On 23 Mar 2010, at 20:32, Пётр Прохоренков wrote: > > I'm trying to write a grammar file for parsing expressions. The main part >> goes as following: >> >> %left '-' '+'; >> expr: expr '+' expr >> | expr '-' expr >> // Other operators... >> | expr expr >> | const >> | id >> ; >> >> "expr expr" here is function application, former expr is the function and >> latter expression is an argument (as in Haskell). >> > > You check the .y file of Hugs <http://haskell.org/hugs/>. > > > I don't understand what is wrong with %prec as documentation says it >> assigns >> precedence to rule. >> > > If you look into the .output file for the parsing position "." in the state > of the conflicting rules, then it uses the precedences of the two token > immediately before and after that dot (one token from each). If there are > not two such tokens available, because they way the rules have been written, > the method fails. > > Hans > > _______________________________________________ help-bison@gnu.org http://lists.gnu.org/mailman/listinfo/help-bison
