mirror of
https://github.com/dart-lang/sdk
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7a540d2f85
Change-Id: Ic12edd3e76ba1f8b9fb096c96e310e7253cc6ac6 Reviewed-on: https://dart-review.googlesource.com/14722 Commit-Queue: Bob Nystrom <rnystrom@google.com> Reviewed-by: Régis Crelier <regis@google.com>
103 lines
3.1 KiB
Dart
103 lines
3.1 KiB
Dart
// Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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/// Dart test verifying that the parser can handle type parameterization of
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/// function declarations and function invocations. Variant of code from
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/// DEP #22, adjusted to use generic top level functions.
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library generic_functions_test;
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import "package:expect/expect.dart";
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class BinaryTreeNode<K extends Comparable<K>, V> {
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final K _key;
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final V _value;
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final BinaryTreeNode<K, V> _left;
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final BinaryTreeNode<K, V> _right;
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BinaryTreeNode(this._key, this._value,
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{BinaryTreeNode<K, V> left: null, BinaryTreeNode<K, V> right: null})
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: _left = left,
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_right = right;
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BinaryTreeNode<K, V> insert(K key, V value) {
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int c = key.compareTo(_key);
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if (c == 0) return this;
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var _insert = (BinaryTreeNode<K, V> t, K key, V value) =>
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insertOpt<K, V>(t, key, value);
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BinaryTreeNode<K, V> left = _left;
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BinaryTreeNode<K, V> right = _right;
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if (c < 0) {
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left = _insert(_left, key, value);
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} else {
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right = _insert(_right, key, value);
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}
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return new BinaryTreeNode<K, V>(_key, _value, left: left, right: right);
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}
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BinaryTreeNode<K, U> map<U>(U f(V x)) {
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var _map = (BinaryTreeNode<K, V> t, U f(V x)) => mapOpt<K, V, U>(t, f);
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return new BinaryTreeNode<K, U>(_key, f(_value),
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left: _map(_left, f), right: _map(_right, f));
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}
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S foldPre<S>(S init, S f(V t, S s)) {
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var _fold = (BinaryTreeNode<K, V> t, S s, S f(V t, S s)) =>
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foldPreOpt<K, V, S>(t, s, f);
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S s = init;
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s = f(_value, s);
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s = _fold(_left, s, f);
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s = _fold(_right, s, f);
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return s;
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}
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}
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BinaryTreeNode<K2, V2> insertOpt<K2 extends Comparable<K2>, V2>(
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BinaryTreeNode<K2, V2> t, K2 key, V2 value) {
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return (t == null) ? new BinaryTreeNode(key, value) : t.insert(key, value);
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}
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BinaryTreeNode<K, U> mapOpt<K extends Comparable<K>, V, U>(
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BinaryTreeNode<K, V> t, U f(V x)) {
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return (t == null) ? null : t.map<U>(f);
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}
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S foldPreOpt<K2 extends Comparable<K2>, V, S>(
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BinaryTreeNode<K2, V> t, S init, S f(V t, S s)) {
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return (t == null) ? init : t.foldPre<S>(init, f);
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}
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class BinaryTree<K extends Comparable<K>, V> {
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final BinaryTreeNode<K, V> _root;
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BinaryTree._internal(this._root);
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BinaryTree.empty() : this._internal(null);
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BinaryTree<K, V> insert(K key, V value) {
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BinaryTreeNode<K, V> root = insertOpt<K, V>(_root, key, value);
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return new BinaryTree<K, V>._internal(root);
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}
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BinaryTree<K, U> map<U>(U f(V x)) {
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BinaryTreeNode<K, U> root = mapOpt<K, V, U>(_root, f);
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return new BinaryTree<K, U>._internal(root);
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}
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S foldPre<S>(S init, S f(V t, S s)) {
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return foldPreOpt<K, V, S>(_root, init, f);
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}
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}
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main() {
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BinaryTree<num, String> sT = new BinaryTree<num, String>.empty();
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sT = sT.insert(0, "");
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sT = sT.insert(1, " ");
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sT = sT.insert(2, " ");
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sT = sT.insert(3, " ");
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BinaryTree<num, num> iT = sT.map<num>((String s) => s.length);
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Expect.equals(iT.foldPre<num>(0, (num i, num s) => i + s), 6);
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}
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