hi guys, in the typical calculator example that allows statements like: a=2+3 it is fairly easy to parse and interpret code like b=a+1 but what if you could assign '+' to a variable: p=+ now that a variable could be an number or an operator, it's hard to parse eg. how can i parse string "a p b" ? what is the grammar? is it something like this: expr: variable variable variable ? after a bit of thought, i wondered whether i could feedback type information to the lexer so, when i parse 'a=2+3', i tell the lexer that a is a number then with input 'b=a+1", the lexer would produce: VARIABLE '=' VARIABLE NUMBER '+' LITERAL (the token NUMBER indicate's the variable's type) and with input "a p 1", the lexer would produce: VARIABLE NUMBER VARIABLE OPERATOR LITERAL
will lookahead make this scheme unworkable? can i make use of multiple lexer/parsers? any pointer in the right direction appreciated. ta, jack _______________________________________________ help-bison@gnu.org http://lists.gnu.org/mailman/listinfo/help-bison
