[flang-commits] [flang] [llvm] [Flang] Introduce *Value classes with unittests (PR #216958)

[Michael Kruse via flang-commits]

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@@ -0,0 +1,250 @@
+//===-- include/flang/Evaluate/character-value.h ----------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FORTRAN_EVALUATE_CHARACTER_VALUE_H_
+#define FORTRAN_EVALUATE_CHARACTER_VALUE_H_
+
+#include "flang/Evaluate/common.h"
+#include "flang/Evaluate/object-sizes.h"
+#include "flang/Evaluate/type.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cstddef>
+#include <iosfwd>
+#include <optional>
+#include <string>
+
+namespace Fortran::evaluate::value {
+class CharacterValueImpl;
+
+/// A character string with dynamic character representation with
+/// std::basic_string-like API.
+///
+/// The character type is dynamic between char, char16_t, and char32_t. As being
+/// able to represent all values, char32_t is used when passing single
+/// characters. It is also kind-aware, i.e. knows which CHARACTER kind it
+/// currently represents.
+///
+/// The implementation is hidden from this header using a pImpl-like idiom.
+class CharacterValue {
+public:
+  // rule-of-five
+  ~CharacterValue();
+  CharacterValue(const CharacterValue &);
+  CharacterValue(CharacterValue &&);
+  CharacterValue &operator=(const CharacterValue &);
+  CharacterValue &operator=(CharacterValue &&);
+
+  // ctors
+
+  /// A default-initialized CharacterValue is in a so-called "monostate"; it
+  /// represents an empty string, but its kind is not yet known. Not all
+  /// operations are supported in this state.
+  CharacterValue();
+
+  explicit CharacterValue(int kind, std::string s);
+  explicit CharacterValue(int kind, std::u16string s);
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Meinersbur wrote:

`Scalar<Type<TypeCategory::Character, 2>>` is `std::u16string`

https://github.com/llvm/llvm-project/pull/216958