javascript - Adding functions to bison/jison calculator language -

javascript - Adding functions to bison/jison calculator language -

i'm trying expand jison calculator example simple functions. i'm rather new parsing , bison/jison, bit of have far:

/* lexical grammar */ %lex %{ var funcs = { pow: function(a, b) { homecoming math.pow(a, b); }, test: function(a) { homecoming a*2; } } %} %% \s+ /* skip whitespace */ [0-9]+("."[0-9]+)?\b homecoming 'number' [a-za-z]+ homecoming 'name' "," homecoming ',' "*" homecoming '*' "(" homecoming '(' ")" homecoming ')' <<eof>> homecoming 'eof' . homecoming 'invalid' /lex %start expressions %% /* language grammar */ expressions : e eof { homecoming $1; } ; expression_list : expression_list ',' e | e ; e : e '*' e {$$ = $1*$3;} | '(' e ')' {$$ = $2;} | number {$$ = number(yytext);} | name '(' expression_list ')' {$$ = funcs[$name]($expression_list);} ;

the problem functions getting 1 argument passed them. example:

test(2) -> 4 pow(2,3) -> null

in fact, if console.log arguments of pow, appears b isn't defined. why isn't parsing whole look list before sending function?

you need action in first production expression_list. default action copies $1 $$, means appended value discarded.

javascript parsing bison jison