| Andrew Scull | 5e1ddfa | 2018-08-14 10:06:54 +0100 | [diff] [blame] | 1 | //===-- None.h - Simple null value for implicit construction ------*- C++ -*-=// |
| 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | // |
| 10 | // This file provides None, an enumerator for use in implicit constructors |
| 11 | // of various (usually templated) types to make such construction more |
| 12 | // terse. |
| 13 | // |
| 14 | //===----------------------------------------------------------------------===// |
| 15 | |
| 16 | #ifndef LLVM_ADT_NONE_H |
| 17 | #define LLVM_ADT_NONE_H |
| 18 | |
| 19 | namespace llvm { |
| Andrew Scull | cdfcccc | 2018-10-05 20:58:37 +0100 | [diff] [blame^] | 20 | /// A simple null object to allow implicit construction of Optional<T> |
| Andrew Scull | 5e1ddfa | 2018-08-14 10:06:54 +0100 | [diff] [blame] | 21 | /// and similar types without having to spell out the specialization's name. |
| 22 | // (constant value 1 in an attempt to workaround MSVC build issue... ) |
| 23 | enum class NoneType { None = 1 }; |
| 24 | const NoneType None = NoneType::None; |
| 25 | } |
| 26 | |
| 27 | #endif |