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https://github.com/carbon-language/carbon-lang.git
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Jon Ross-Perkins
d96ede7144
A quick check suggests this isn't necessary -- probably because the implicit enum cast is used for comparisons. I think this adds a lot to the boilerplate feel of these types, so if we can remove it there's a lot less sharing to do.
83 lines
3.0 KiB
C++
83 lines
3.0 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 CARBON_TOOLCHAIN_PARSER_PARSE_NODE_KIND_H_
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#define CARBON_TOOLCHAIN_PARSER_PARSE_NODE_KIND_H_
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#include <cstdint>
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#include <iterator>
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#include "common/ostream.h"
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#include "llvm/ADT/StringRef.h"
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namespace Carbon {
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// A class wrapping an enumeration of the different kinds of nodes in the parse
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// tree.
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//
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// Rather than using a raw enumerator for each distinct kind of node produced by
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// the parser, we wrap the enumerator in a class to expose a more rich API
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// including bidirectional mappings to string spellings of the different kinds
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// and any relevant classification.
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//
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// Instances of this type should always be created using the `constexpr` static
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// member functions. These instances are designed specifically to be usable in
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// `case` labels of `switch` statements just like an enumerator would.
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class ParseNodeKind {
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// Note that this must be declared earlier in the class so that its type can
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// be used, for example in the conversion operator.
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enum class KindEnum : uint8_t {
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#define CARBON_PARSE_NODE_KIND(Name) Name,
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#include "toolchain/parser/parse_node_kind.def"
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};
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public:
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// `clang-format` has a bug with spacing around `->` returns in macros. See
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// https://bugs.llvm.org/show_bug.cgi?id=48320 for details.
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#define CARBON_PARSE_NODE_KIND(Name) \
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static constexpr auto Name()->ParseNodeKind { \
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return ParseNodeKind(KindEnum::Name); \
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}
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#include "toolchain/parser/parse_node_kind.def"
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// The default constructor is deleted because objects of this type should
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// always be constructed using the above factory functions for each unique
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// kind.
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ParseNodeKind() = delete;
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// Gets a friendly name for the token for logging or debugging.
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[[nodiscard]] auto name() const -> llvm::StringRef;
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// Enable conversion to our private enum, including in a `constexpr` context,
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// to enable usage in `switch` and `case`. The enum remains private and
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// nothing else should be using this function.
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// NOLINTNEXTLINE(google-explicit-constructor)
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constexpr operator KindEnum() const { return kind_; }
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void Print(llvm::raw_ostream& out) const { out << name(); }
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// Returns true if the node is bracketed; otherwise, child_count is used.
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auto has_bracket() const -> bool;
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// Returns the bracketing node kind for the current node kind. Requires that
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// has_bracket is true.
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auto bracket() const -> ParseNodeKind;
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// Returns the number of children that the node must have, often 0. Requires
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// that has_bracket is false.
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auto child_count() const -> int32_t;
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private:
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constexpr explicit ParseNodeKind(KindEnum k) : kind_(k) {}
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KindEnum kind_;
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};
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// We expect the parse node kind to fit compactly into 8 bits.
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static_assert(sizeof(ParseNodeKind) == 1, "Kind objects include padding!");
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} // namespace Carbon
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#endif // CARBON_TOOLCHAIN_PARSER_PARSE_NODE_KIND_H_
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