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41 lines
895 B
C++
41 lines
895 B
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_CONS_LIST_H_
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#define EXECUTABLE_SEMANTICS_INTERPRETER_CONS_LIST_H_
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namespace Carbon {
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template <class T>
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struct Stack;
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template <class T>
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struct Cons {
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friend struct Stack<T>;
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private:
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Cons(T e, Cons* n) : curr(e), next(n) {}
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const T curr;
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Cons* const next;
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// Cons cells are part of a "persistent data structure" and are thus
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// immutable.
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Cons& operator=(const Cons&) = delete;
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Cons& operator=(Cons&&) = delete;
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};
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template <class T>
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auto Length(Cons<T>* ls) -> unsigned int {
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if (ls) {
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return 1 + Length(ls->next);
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} else {
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return 0;
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}
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}
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} // namespace Carbon
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#endif // EXECUTABLE_SEMANTICS_INTERPRETER_CONS_LIST_H_
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