add_function
$$ = add_function(symbolrename($1, $3), $2);
$$ = add_function(symbolrename($1, $3), $2);
$$ = add_function(symbolrename($1, $3), $2);
$$ = add_function(symbolrename($1, $3), $2);
$$ = add_function(symbolrename(name, $2), $1);
$$ = add_function(symbolrename($1, $3), $2);
sym_t *add_function(sym_t *, parameter_list);