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https://github.com/carbon-language/carbon-lang.git
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Geoff RomerandJon Meow
6ac3adfa53
`Pattern` is intended to pilot some changes I would like to apply to all our sum types: - The alternatives are expressed as derived classes rather than members of a `std::variant`. - The alternatives are classes in the [style guide sense](https://google.github.io/styleguide/cppguide.html#Structs_vs._Classes), meaning they can have invariants, but can't have public data members. - Creating an object is expressed using a constructor rather than a factory function. - Accessing an alternative is expressed as a cast (using LLVM's RTTI system) rather than `std::get` or a `Get` method. Co-authored-by: Jon Meow <46229924+jonmeow@users.noreply.github.com>
49 lines
1.3 KiB
C++
49 lines
1.3 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#ifndef EXECUTABLE_SEMANTICS_AST_MEMBER_H_
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#define EXECUTABLE_SEMANTICS_AST_MEMBER_H_
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#include <string>
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#include "common/ostream.h"
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#include "executable_semantics/ast/expression.h"
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#include "executable_semantics/ast/pattern.h"
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#include "llvm/Support/Compiler.h"
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namespace Carbon {
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enum class MemberKind { FieldMember };
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struct FieldMember {
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static constexpr MemberKind Kind = MemberKind::FieldMember;
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// TODO: split this into a non-optional name and a type, initialized by
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// a constructor that takes a BindingPattern and handles errors like a
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// missing name.
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const BindingPattern* binding;
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};
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struct Member {
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static auto MakeFieldMember(int line_num, const BindingPattern* binding)
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-> Member*;
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auto GetFieldMember() const -> const FieldMember&;
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void Print(llvm::raw_ostream& out) const;
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LLVM_DUMP_METHOD void Dump() const { Print(llvm::errs()); }
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inline auto tag() const -> MemberKind {
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return std::visit([](const auto& t) { return t.Kind; }, value);
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}
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int line_num;
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private:
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std::variant<FieldMember> value;
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};
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} // namespace Carbon
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#endif // EXECUTABLE_SEMANTICS_AST_MEMBER_H_
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