expression.hpp

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// Copyright (c) 2024 Simons Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0.txt
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Authors: Thomas Hahn
 
#pragma once
 
#include "./utils.hpp"
 
#include <tuple>
#include <utility>
 
namespace nda::clef {
 
  namespace tags {
 
    struct function {};
 
    struct subscript {};
 
    struct terminal {};
 
    struct if_else {};
 
    struct unary_op {};
 
    struct binary_op {};
 
  } // namespace tags
 
  template <typename Tag, typename... Ts>
  struct expr {
    using childs_t = std::tuple<Ts...>;
 
    childs_t childs;
 
    expr(expr const &) = default;
 
    expr(expr &&ex) noexcept : childs(std::move(ex.childs)) {}
 
    expr &operator=(expr const &) = delete;
 
    expr &operator=(expr &&) = default;
 
    template <typename... Us>
    expr(Tag, Us &&...us) : childs(std::forward<Us>(us)...) {}
 
    template <typename... Args>
    auto operator[](Args &&...args) const {
      return expr<tags::subscript, expr, expr_storage_t<Args>...>{tags::subscript(), *this, std::forward<Args>(args)...};
    }
 
    template <typename... Args>
    auto operator()(Args &&...args) const {
      return expr<tags::function, expr, expr_storage_t<Args>...>{tags::function(), *this, std::forward<Args>(args)...};
    }
  };
 
  namespace detail {
 
    // Specialization of ph_set for nda::clef::expr types.
    template <typename Tag, typename... Ts>
    struct ph_set<expr<Tag, Ts...>> : ph_set<Ts...> {};
 
    // Specialization of is_lazy_impl for nda::clef::expr types (always true).
    template <typename Tag, typename... Ts>
    constexpr bool is_lazy_impl<expr<Tag, Ts...>> = true;
 
    // Specialization of force_copy_in_expr_impl for nda::clef::expr types (always true).
    template <typename Tag, typename... Ts>
    constexpr bool force_copy_in_expr_impl<expr<Tag, Ts...>> = true;
 
  } // namespace detail
 
} // namespace nda::clef