cpp-remap/include/remap/remap.hpp

//
//  remap.hpp
//  remap
//
//  Created by Sam Jaffe on 9/16/18.
//
#pragma once

#include <map>
#include <unordered_map>

/*
 * A remap referres to a "value re-mapping object". This is used to allow us to
 * rename
 */
template <typename T, typename Impl> class remap_base {
public:
  using value_type = typename Impl::value_type;
  using key_type = typename Impl::key_type;
  using mapped_type = typename Impl::mapped_type;

private:
  Impl impl_;

public:
  remap_base(std::initializer_list<value_type> mappings) : impl_(mappings) {}

  mapped_type const & operator[](T const & value) const {
    auto it = impl_.find(value);
    return (it != impl_.end()) ? it->second : value;
  }
};

template <typename T, typename Compare = std::less<T>,
          typename Alloc = std::allocator<std::pair<T const, T>>>
using remap = remap_base<T, std::map<T, T, Compare, Alloc>>;
template <typename T, typename Hash = std::hash<T>,
          typename Equal = std::equal_to<T>,
          typename Alloc = std::allocator<std::pair<T const, T>>>
using unordered_remap =
    remap_base<T, std::unordered_map<T, T, Hash, Equal, Alloc>>;