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int disambiguator(struct state *old, struct state *new) {
// printf("Old tree: ");
// print_parse_tree2(old);
// printf("New tree: ");
// print_parse_tree2(new);
if (old->start_idx != new->start_idx) {
// printf("\t\tIGNORING "); print_parse_tree2(old);
// printf("\t\tVS: "); print_parse_tree2(new);
return 2;
}
// Prefer the earlier parsings in the grammar when two entirely different
// productions are taken.
if (old->production_id != new->production_id)
return old->production_id < new->production_id
? 0 : 1;
// If they're the same production ...
prod_id_t prod = old->production_id;
if (PRODUCTION_ID_TO_SYMBOL[prod] == SYMBOL_EXPR) {
if (PRODUCTION_ID_TO_PRODUCTION[prod][1] == SYMBOL_OP) {
struct token *old_tok = find_token(old, 1),
*new_tok = find_token(new, 1);
char *old_s = old_tok->string, *new_s = new_tok->string;
const char *precedence[] = {".", "->", "*", "/", "%", "+", "-",
"<<", ">>", "<", "<=", ">", ">=", "==", "!=", "&", "|", "&&",
"||", "=", "+=", "-=", "*=", "/=", "%=", "<<=", ">>=", "&=",
"^=", "|=", ",", 0};
if (strcmp(old_s, new_s)) {
for (const char **p = precedence; *p; p++) {
if (!strcmp(old_s, *p)) {
return 1;
} else if (!strcmp(new_s, *p)) {
return 0;
}
}
// BAD!
return 2;
} else {
// Associate RIGHT
if (old_tok < new_tok) return 1;
else if (old_tok > new_tok) return 0;
}
}
}
printf("TOTALLY UNKNOWN!\n");
return 2;
}
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