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67 lines
2.2 KiB
C++
67 lines
2.2 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_INTERPRETER_FIELD_PATH_H_
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#define EXECUTABLE_SEMANTICS_INTERPRETER_FIELD_PATH_H_
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#include <string>
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#include <vector>
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#include "common/ostream.h"
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#include "llvm/Support/Compiler.h"
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namespace Carbon {
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// Given some initial Value, a FieldPath identifies a sub-Value within it,
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// in much the same way that a file path identifies a file within some
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// directory. FieldPaths are relative rather than absolute: the initial
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// Value is specified by the context in which the FieldPath is used, not
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// by the FieldPath itself.
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//
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// A FieldPath consists of a series of steps, which specify how to
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// incrementally navigate from a Value to one of its fields. Currently
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// there is only one kind of step, a string specifying a child field by name,
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// but that may change as Carbon develops. Note that an empty FieldPath
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// refers to the initial Value itself.
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class FieldPath {
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public:
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// Constructs an empty FieldPath.
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FieldPath() = default;
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// Constructs a FieldPath consisting of a single step.
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explicit FieldPath(std::string name) : components_({std::move(name)}) {}
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FieldPath(const FieldPath&) = default;
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FieldPath(FieldPath&&) = default;
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auto operator=(const FieldPath&) -> FieldPath& = default;
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auto operator=(FieldPath&&) -> FieldPath& = default;
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// Returns whether *this is empty.
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auto IsEmpty() const -> bool { return components_.empty(); }
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// Appends `name` to the end of *this.
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auto Append(std::string name) -> void {
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components_.push_back(std::move(name));
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}
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void Print(llvm::raw_ostream& out) const {
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for (const std::string& component : components_) {
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out << "." << component;
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}
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}
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LLVM_DUMP_METHOD void Dump() const { Print(llvm::errs()); }
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private:
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// The representation of FieldPath describes how to locate a Value within
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// another Value, so its implementation details are tied to the implementation
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// details of Value.
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friend class Value;
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std::vector<std::string> components_;
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};
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} // namespace Carbon
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#endif // EXECUTABLE_SEMANTICS_INTERPRETER_FIELD_PATH_H_
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