Files
carbon-lang/executable_semantics/ast/static_scope.h
T

69 lines
2.3 KiB
C++

// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#ifndef EXECUTABLE_SEMANTICS_AST_STATIC_SCOPE_H_
#define EXECUTABLE_SEMANTICS_AST_STATIC_SCOPE_H_
#include <string>
#include <unordered_map>
#include <variant>
#include <vector>
#include "executable_semantics/ast/ast_node.h"
#include "executable_semantics/ast/source_location.h"
#include "executable_semantics/common/nonnull.h"
namespace Carbon {
class NamedEntity : public virtual AstNode {
public:
~NamedEntity() override = 0;
NamedEntity() = default;
// TODO: This is unused, but is intended for casts after lookup.
auto kind() const -> NamedEntityKind {
return static_cast<NamedEntityKind>(root_kind());
}
};
// Maps the names visible in a given scope to the entities they name.
// A scope may have parent scopes, whose names will also be visible in the
// child scope.
class StaticScope {
public:
// Defines `name` to be `entity` in this scope, or reports a compilation error
// if `name` is already defined in this scope.
void Add(std::string name, Nonnull<const NamedEntity*> entity);
// Make `parent` a parent of this scope.
// REQUIRES: `parent` is not already a parent of this scope.
void AddParent(Nonnull<StaticScope*> parent) {
parent_scopes_.push_back(parent);
}
// Returns the nearest definition of `name` in the ancestor graph of this
// scope, or reports a compilation error at `source_loc` there isn't exactly
// one such definition.
auto Resolve(const std::string& name, SourceLocation source_loc) const
-> Nonnull<const NamedEntity*>;
private:
// Equivalent to Resolve, but returns `nullopt` instead of raising an error
// if no definition can be found. Still raises a compilation error if more
// than one definition is found.
auto TryResolve(const std::string& name, SourceLocation source_loc) const
-> std::optional<Nonnull<const NamedEntity*>>;
// Maps locally declared names to their entities.
std::unordered_map<std::string, Nonnull<const NamedEntity*>> declared_names_;
// A list of scopes used for name lookup within this scope.
std::vector<Nonnull<StaticScope*>> parent_scopes_;
};
} // namespace Carbon
#endif // EXECUTABLE_SEMANTICS_AST_STATIC_SCOPE_H_