Function llama_grammar_init

llama.cpp:8066–8104

//

struct llama_grammar * llama_grammar_init(
            const llama_grammar_element ** rules,
                                 size_t    n_rules,
                                 size_t    start_rule_index) {
    const llama_grammar_element * pos;

    // copy rule definitions into vectors
    std::vector<std::vector<llama_grammar_element>> vec_rules(n_rules);
    for (size_t i = 0; i < n_rules; i++) {
        for (pos = rules[i]; pos->type != LLAMA_GRETYPE_END; pos++) {
            vec_rules[i].push_back(*pos);
        }
        vec_rules[i].push_back({LLAMA_GRETYPE_END, 0});
    }

    // loop over alternates of start rule to build initial stacks
    std::vector<std::vector<const llama_grammar_element *>> stacks;
    pos = rules[start_rule_index];
    do {
        std::vector<const llama_grammar_element *> stack;
        if (!llama_grammar_is_end_of_sequence(pos)) {
            // if alternate is nonempty, add to stack
            stack.push_back(pos);
        }
        llama_grammar_advance_stack(vec_rules, stack, stacks);
        while (!llama_grammar_is_end_of_sequence(pos)) {
            // scan to end of alternate def
            pos++;
        }
        if (pos->type == LLAMA_GRETYPE_ALT) {
            // there's another alternate def of this rule to process
            pos++;
        } else {
            break;
        }
    } while (true);

    return new llama_grammar{ std::move(vec_rules), std::move(stacks), {} };
}

void llama_grammar_free(struct llama_grammar * grammar) {
    delete grammar;