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carbon-lang/executable_semantics/interpreter/frame.h
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Jon Meow 56dc4ae375 Rename Ptr<T> to Nonnull<T*> (#832)
Note that ptr.h also includes an enable_if change, to help avoid https://bugs.llvm.org/show_bug.cgi?id=51881
2021-09-16 19:22:57 -07:00

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// 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_INTERPRETER_FRAME_H_
#define EXECUTABLE_SEMANTICS_INTERPRETER_FRAME_H_
#include <string>
#include <vector>
#include "common/ostream.h"
#include "executable_semantics/interpreter/action.h"
#include "executable_semantics/interpreter/address.h"
#include "executable_semantics/interpreter/dictionary.h"
#include "executable_semantics/interpreter/stack.h"
#include "llvm/Support/Compiler.h"
namespace Carbon {
using Env = Dictionary<std::string, Address>;
struct Scope {
explicit Scope(Env values) : Scope(values, std::vector<std::string>()) {}
Scope(Env values, std::vector<std::string> l)
: values(values), locals(std::move(l)) {}
Env values;
std::vector<std::string> locals;
};
// A frame represents either a function call or a delimited continuation.
struct Frame {
Frame(const Frame&) = delete;
Frame& operator=(const Frame&) = delete;
Frame(std::string n, Stack<Nonnull<Scope*>> s, Stack<Nonnull<Action*>> c)
: name(std::move(std::move(n))), scopes(s), todo(c), continuation() {}
void Print(llvm::raw_ostream& out) const;
LLVM_DUMP_METHOD void Dump() const { Print(llvm::errs()); }
// The name of the function.
std::string name;
// If the frame represents a function call, the bottom scope
// contains the parameter-argument bindings for this function
// call. The rest of the scopes contain local variables defined by
// blocks within the function. The scope at the top of the stack is
// the current scope and its environment is the one used for looking
// up the value associated with a variable.
Stack<Nonnull<Scope*>> scopes;
// The actions that need to be executed in the future of the
// current function call. The top of the stack is the action
// that is executed first.
Stack<Nonnull<Action*>> todo;
// If this frame is the bottom frame of a continuation, then it stores
// the address of the continuation.
std::optional<Address> continuation;
};
} // namespace Carbon
#endif // EXECUTABLE_SEMANTICS_INTERPRETER_FRAME_H_