expression_type.hpp

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// Copyright (c) Sleipnir contributors
 
#pragma once
 
#include <stdint.h>
 
#include <fmt/base.h>
 
#include "sleipnir/util/unreachable.hpp"
 
namespace slp {
 
/// Expression type.
///
/// Used for autodiff caching.
enum class ExpressionType : uint8_t {
  /// There is no expression.
  NONE,
  /// The expression is a constant.
  CONSTANT,
  /// The expression is composed of linear and lower-order operators.
  LINEAR,
  /// The expression is composed of quadratic and lower-order operators.
  QUADRATIC,
  /// The expression is composed of nonlinear and lower-order operators.
  NONLINEAR
};
 
}  // namespace slp
 
/// Formatter for ExpressionType.
template <>
struct fmt::formatter<slp::ExpressionType> {
  /// Parse format string.
  ///
  /// @param ctx Format parse context.
  /// @return Format parse context iterator.
  constexpr auto parse(fmt::format_parse_context& ctx) {
    return m_underlying.parse(ctx);
  }
 
  /// Format ExpressionType.
  ///
  /// @tparam FmtContext Format context type.
  /// @param type Expression type.
  /// @param ctx Format context.
  /// @return Format context iterator.
  template <typename FmtContext>
  auto format(const slp::ExpressionType& type, FmtContext& ctx) const {
    using enum slp::ExpressionType;
 
    switch (type) {
      case NONE:
        return m_underlying.format("none", ctx);
      case CONSTANT:
        return m_underlying.format("constant", ctx);
      case LINEAR:
        return m_underlying.format("linear", ctx);
      case QUADRATIC:
        return m_underlying.format("quadratic", ctx);
      case NONLINEAR:
        return m_underlying.format("nonlinear", ctx);
      default:
        slp::unreachable();
    }
  }
 
 private:
  fmt::formatter<const char*> m_underlying;
};