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144 lines
4.4 KiB
C++
144 lines
4.4 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_DECLARATION_H_
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#define EXECUTABLE_SEMANTICS_AST_DECLARATION_H_
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#include <list>
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#include <string>
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#include "common/ostream.h"
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#include "executable_semantics/ast/class_definition.h"
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#include "executable_semantics/ast/function_definition.h"
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#include "executable_semantics/ast/member.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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// Abstract base class of all AST nodes representing patterns.
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//
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// Declaration and its derived classes support LLVM-style RTTI, including
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// llvm::isa, llvm::cast, and llvm::dyn_cast. To support this, every
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// class derived from Declaration must provide a `classof` operation, and
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// every concrete derived class must have a corresponding enumerator
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// in `Kind`; see https://llvm.org/docs/HowToSetUpLLVMStyleRTTI.html for
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// details.
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class Declaration {
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public:
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enum class Kind {
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FunctionDeclaration,
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ClassDeclaration,
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ChoiceDeclaration,
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VariableDeclaration,
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};
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Declaration(const Member&) = delete;
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Declaration& operator=(const Member&) = delete;
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// Returns the enumerator corresponding to the most-derived type of this
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// object.
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auto Tag() const -> Kind { return tag; }
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auto LineNumber() const -> int { return line_num; }
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void Print(llvm::raw_ostream& out) const;
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protected:
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// Constructs a Declaration representing syntax at the given line number.
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// `tag` must be the enumerator corresponding to the most-derived type being
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// constructed.
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Declaration(Kind tag, int line_num) : tag(tag), line_num(line_num) {}
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private:
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const Kind tag;
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int line_num;
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};
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class FunctionDeclaration : public Declaration {
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public:
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FunctionDeclaration(const FunctionDefinition* definition)
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: Declaration(Kind::FunctionDeclaration, definition->line_num),
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definition(definition) {}
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static auto classof(const Declaration* decl) -> bool {
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return decl->Tag() == Kind::FunctionDeclaration;
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}
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auto Definition() const -> const FunctionDefinition& { return *definition; }
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private:
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const FunctionDefinition* definition;
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};
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class ClassDeclaration : public Declaration {
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public:
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ClassDeclaration(int line_num, std::string name, std::list<Member*> members)
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: Declaration(Kind::ClassDeclaration, line_num),
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definition({.line_num = line_num,
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.name = std::move(name),
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.members = std::move(members)}) {}
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static auto classof(const Declaration* decl) -> bool {
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return decl->Tag() == Kind::ClassDeclaration;
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}
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auto Definition() const -> const ClassDefinition& { return definition; }
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private:
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ClassDefinition definition;
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};
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class ChoiceDeclaration : public Declaration {
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public:
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ChoiceDeclaration(
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int line_num, std::string name,
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std::list<std::pair<std::string, const Expression*>> alternatives)
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: Declaration(Kind::ChoiceDeclaration, line_num),
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name(std::move(name)),
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alternatives(std::move(alternatives)) {}
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static auto classof(const Declaration* decl) -> bool {
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return decl->Tag() == Kind::ChoiceDeclaration;
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}
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auto Name() const -> const std::string& { return name; }
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auto Alternatives() const
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-> const std::list<std::pair<std::string, const Expression*>>& {
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return alternatives;
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}
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private:
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std::string name;
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std::list<std::pair<std::string, const Expression*>> alternatives;
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};
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// Global variable definition implements the Declaration concept.
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class VariableDeclaration : public Declaration {
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public:
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VariableDeclaration(int line_num, const BindingPattern* binding,
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const Expression* initializer)
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: Declaration(Kind::VariableDeclaration, line_num),
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binding(binding),
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initializer(initializer) {}
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static auto classof(const Declaration* decl) -> bool {
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return decl->Tag() == Kind::VariableDeclaration;
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}
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auto Binding() const -> const BindingPattern* { return binding; }
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auto Initializer() const -> const Expression* { return initializer; }
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private:
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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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const Expression* initializer;
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};
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} // namespace Carbon
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#endif // EXECUTABLE_SEMANTICS_AST_DECLARATION_H_
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