mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-25 10:20:12 +01:00
Jon Meow
47325be112
This also eliminates the ctad wrapper for Stack: I think the leaning is to remove it. It felt worth keeping the constructor because constructing with a single element is a common use-case. Adds a single-argument constructor for Scope because the `std::list<std::string>()` is common, and eliding it is consistent with what we've done for things like tuples. I was considering a vector constructor due to the double-Push on line 1139, but thought the Push() semantics may mean that it's better not to provide.
75 lines
2.0 KiB
C++
75 lines
2.0 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_INTERPRETER_STACK_H_
|
|
#define EXECUTABLE_SEMANTICS_INTERPRETER_STACK_H_
|
|
|
|
#include <cstddef>
|
|
#include <iterator>
|
|
#include <vector>
|
|
|
|
#include "common/check.h"
|
|
|
|
namespace Carbon {
|
|
|
|
// A stack data structure.
|
|
template <class T>
|
|
struct Stack {
|
|
using const_iterator = typename std::vector<T>::const_reverse_iterator;
|
|
|
|
// Creates an empty instance.
|
|
Stack() = default;
|
|
|
|
// Creates an instance containing just `x`.
|
|
explicit Stack(T x) : Stack() { Push(std::move(x)); }
|
|
|
|
// Pushes `x` onto the top of the stack.
|
|
void Push(T x) { elements.push_back(std::move(x)); }
|
|
|
|
// Removes and returns the top element of the stack.
|
|
//
|
|
// - Requires: !this->IsEmpty()
|
|
auto Pop() -> T {
|
|
CHECK(!IsEmpty()) << "Can't pop from empty stack.";
|
|
auto r = std::move(elements.back());
|
|
elements.pop_back();
|
|
return r;
|
|
}
|
|
|
|
// Removes the top `n` elements of the stack.
|
|
//
|
|
// - Requires: n >= 0 && n <= Count()
|
|
void Pop(int n) {
|
|
CHECK(n >= 0) << "Negative pop count disallowed.";
|
|
CHECK(static_cast<size_t>(n) <= elements.size())
|
|
<< "Can only pop as many elements as stack has.";
|
|
elements.erase(elements.end() - n, elements.end());
|
|
}
|
|
|
|
// Returns the top element of the stack.
|
|
//
|
|
// - Requires: !this->IsEmpty()
|
|
auto Top() const -> T {
|
|
CHECK(!IsEmpty()) << "Empty stack has no Top().";
|
|
return elements.back();
|
|
}
|
|
|
|
// Returns `true` iff `Count() > 0`.
|
|
auto IsEmpty() const -> bool { return elements.empty(); }
|
|
|
|
// Returns the number of elements in `*this`.
|
|
auto Count() const -> int { return elements.size(); }
|
|
|
|
// Iterates over the Stack from top to bottom.
|
|
const_iterator begin() const { return elements.crbegin(); }
|
|
const_iterator end() const { return elements.crend(); }
|
|
|
|
private:
|
|
std::vector<T> elements;
|
|
};
|
|
|
|
} // namespace Carbon
|
|
|
|
#endif // EXECUTABLE_SEMANTICS_INTERPRETER_CONS_LIST_H_
|