llvm/llvm/include/llvm/ADT/StringSwitch.h

//===--- StringSwitch.h - Switch-on-literal-string Construct --------------===/
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//===----------------------------------------------------------------------===/
///
/// \file
///  This file implements the StringSwitch template, which mimics a switch()
///  statement whose cases are string literals.
///
//===----------------------------------------------------------------------===/
#ifndef LLVM_ADT_STRINGSWITCH_H
#define LLVM_ADT_STRINGSWITCH_H

#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Compiler.h"
#include <cassert>
#include <cstring>
#include <optional>

namespace llvm {

/// A switch()-like statement whose cases are string literals.
///
/// The StringSwitch class is a simple form of a switch() statement that
/// determines whether the given string matches one of the given string
/// literals. The template type parameter \p T is the type of the value that
/// will be returned from the string-switch expression. For example,
/// the following code switches on the name of a color in \c argv[i]:
///
/// \code
/// Color color = StringSwitch<Color>(argv[i])
///   .Case("red", Red)
///   .Case("orange", Orange)
///   .Case("yellow", Yellow)
///   .Case("green", Green)
///   .Case("blue", Blue)
///   .Case("indigo", Indigo)
///   .Cases("violet", "purple", Violet)
///   .Default(UnknownColor);
/// \endcode
template<typename T, typename R = T>
class StringSwitch { … };

} // end namespace llvm

#endif // LLVM_ADT_STRINGSWITCH_H