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//
// lager - library for functional interactive c++ programs
// Copyright (C) 2017 Juan Pedro Bolivar Puente
//
// This file is part of lager.
//
// lager is free software: you can redistribute it and/or modify
// it under the terms of the MIT License, as detailed in the LICENSE
// file located at the root of this source code distribution,
// or here: <https://github.com/arximboldi/lager/blob/master/LICENSE>
//
#include <catch2/catch.hpp>
#include <vector>
#include <zug/compose.hpp>
#include <immer/vector.hpp>
#include <immer/box.hpp>
#include <immer/algorithm.hpp>
#include <zug/util.hpp>
#include <lager/lenses.hpp>
#include <lager/lens.hpp>
#include <lager/lenses/attr.hpp>
#include <lager/lenses/at.hpp>
#include <lager/lenses/optional.hpp>
#include <lager/lenses/unbox.hpp>
using val_pair = std::pair<size_t, size_t>;
struct tree
{
size_t value;
val_pair pair {0, 0};
immer::vector<immer::box<tree>> children {};
};
using namespace lager;
using namespace lager::lenses;
using namespace zug;
TEST_CASE("type erased lenses, attr")
{
using te_lens = lens<tree, size_t>;
te_lens value = attr(&tree::value);
te_lens first = attr(&tree::pair) | attr(&val_pair::first);
auto t1 = tree{42, {256, 1115}};
CHECK(view(value, t1) == 42);
CHECK(view(first, t1) == 256);
auto p2 = set(first, t1, 6);
CHECK(p2.pair.first == 6);
CHECK(view(first, p2) == 6);
auto p3 = over(first, t1, [](auto x) { return --x; });
CHECK(view(first, p3) == 255);
CHECK(p3.pair.first == 255);
}
TEST_CASE("type erased lenses, at")
{
auto children = attr(&tree::children);
auto first_child = children | at(0);
lens<tree, std::optional<immer::box<tree>>> te_first_child = first_child;
lens<tree, std::optional<size_t>> te_first_value =
te_first_child | with_opt(unbox | attr(&tree::value));
auto t1 = tree{42};
CHECK(view(te_first_value, t1) == std::nullopt);
CHECK(view(te_first_value, set(first_child, t1, t1)) == std::nullopt);
CHECK(view(te_first_value, set(te_first_child, t1, t1)) == std::nullopt);
t1 = over(children, t1, [](auto vec) {
return vec.push_back(tree{1});
});
CHECK(view(te_first_value, t1) == 1);
CHECK(view(te_first_value, set(first_child, t1, tree{2})) == 2);
CHECK(view(te_first_value, set(te_first_child, t1, tree{3})) == 3);
CHECK(view(te_first_value, set(te_first_value, t1, 4)) == 4);
}
template <typename Member>
auto attr2(Member member)
{
return getset(
[=](auto&& x) -> decltype(auto) {
return std::forward<decltype(x)>(x).*member;
},
[=](auto x, auto&& v) {
x.*member = std::forward<decltype(v)>(v);
return x;
});
};
TEST_CASE("type erased lenses, attr2")
{
using te_lens = lens<tree, size_t>;
te_lens value = attr2(&tree::value);
te_lens first = attr2(&tree::pair) | attr2(&val_pair::first);
auto t1 = tree{42, {256, 1115}};
CHECK(view(value, t1) == 42);
CHECK(view(first, t1) == 256);
auto p2 = set(first, t1, 6);
CHECK(p2.pair.first == 6);
CHECK(view(first, p2) == 6);
auto p3 = over(first, t1, [](auto x) { return --x; });
CHECK(view(first, p3) == 255);
CHECK(p3.pair.first == 255);
}
using lens_list = std::vector<lens<tree, std::optional<size_t>>>;
lens_list all_values(tree t) {
size_t idx = 0;
lens_list res {attr(&tree::value) | force_opt};
for (auto child : t.children) {
auto child_lens = attr(&tree::children)
| at(idx++)
| map_opt(unbox);
for (auto lens : all_values(child.get())) {
res.push_back(child_lens | bind_opt(lens));
}
}
return res;
}
TEST_CASE("type erased lenses, nesting")
{
auto children = attr(&tree::children);
auto t1 = over(children, tree{1}, [](auto vec) {
return vec.push_back(tree{2})
.push_back(tree{3});
});
auto t2 = t1;
t1 = over(children, t1, [=](auto vec) {
return vec.push_back(t1);
});
auto lenses = all_values(t1);
size_t expected1[] = {1, 2, 3, 1, 2, 3};
for (size_t idx = 0; idx < lenses.size(); ++idx) {
CHECK(view(lenses[idx], t1) == expected1[idx]);
}
std::optional<size_t> expected2[] =
{1, 2, 3, std::nullopt, std::nullopt, std::nullopt};
for (size_t idx = 0; idx < lenses.size(); ++idx) {
CHECK(view(lenses[idx], t2) == expected2[idx]);
}
size_t expected3[] = {4, 6, 48, 3, 5, 16};
for (size_t idx = 0; idx < lenses.size(); ++idx) {
auto lens = lenses[idx];
auto expected = expected3[idx];
CHECK(view(lens, set(lens, t1, expected)) == expected);
}
}
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