skeleton_if_node.hpp

// Copyright Take Vos 2020.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include "skeleton_node.hpp"
 
namespace tt {
 
struct skeleton_if_node final: skeleton_node {
    std::vector<statement_vector> children_groups;
    std::vector<std::unique_ptr<formula_node>> expressions;
    std::vector<parse_location> formula_locations;
 
    skeleton_if_node(parse_location location, std::unique_ptr<formula_node> expression) noexcept :
        skeleton_node(location)
    {
        expressions.push_back(std::move(expression));
        formula_locations.push_back(location);
        children_groups.emplace_back();
    }
 
    bool found_elif(parse_location _location, std::unique_ptr<formula_node> expression) noexcept override {
        if (children_groups.size() != expressions.size()) {
            return false;
        }
 
        expressions.push_back(std::move(expression));
        formula_locations.push_back(std::move(_location));
        children_groups.emplace_back();
        return true;
    }
 
    bool found_else(parse_location _location) noexcept override {
        if (children_groups.size() != expressions.size()) {
            return false;
        }
 
        children_groups.emplace_back();
        return true;
    }
 
    bool append(std::unique_ptr<skeleton_node> x) noexcept override {
        append_child(children_groups.back(), std::move(x));
        return true;
    }
 
    void post_process(formula_post_process_context &context) override {
        tt_assert(std::ssize(expressions) == std::ssize(formula_locations));
        for (ssize_t i = 0; i != std::ssize(expressions); ++i) {
            post_process_expression(context, *expressions[i], formula_locations[i]);
        }
 
        for (ttlet &children: children_groups) {
            if (std::ssize(children) > 0) {
                children.back()->left_align();
            }
 
            for (ttlet &child: children) {
                child->post_process(context);
            }
        }
    }
 
    datum evaluate(formula_evaluation_context &context) override {
        tt_axiom(std::ssize(expressions) == std::ssize(formula_locations));
        for (ssize_t i = 0; i != std::ssize(expressions); ++i) {
            if (evaluate_formula_without_output(context, *expressions[i], formula_locations[i])) {
                return evaluate_children(context, children_groups[i]);
            }
        }
        if (std::ssize(children_groups) > std::ssize(expressions)) {
            return evaluate_children(context, children_groups[std::ssize(expressions)]);
        }
        return {};
    }
 
    std::string string() const noexcept override {
        tt_assert(expressions.size() > 0);
        std::string s = "<if ";
        s += to_string(*expressions[0]);
        s += join(transform<std::vector<std::string>>(children_groups[0], [](auto &x) { return to_string(*x); }));
 
        for (size_t i = 1; i != expressions.size(); ++i) {
            s += "elif ";
            s += to_string(*expressions[i]);
            s += join(transform<std::vector<std::string>>(children_groups[i], [](auto &x) { return to_string(*x); }));
        }
 
        if (children_groups.size() != expressions.size()) {
            s += "else ";
            s += join(transform<std::vector<std::string>>(children_groups.back(), [](auto &x) { return to_string(*x); }));
        }
 
        s += ">";
        return s;
    }
};
 
}