// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.Diagnostics;
using System.Linq;
using ICSharpCode.AvalonEdit.Document;
namespace ICSharpCode.AvalonEdit.Xml
{
static class ExtensionMethods
{
// Copied from ICSharpCode.SharpDevelop.Dom.ExtensionMethods
/// <summary>
/// Converts a recursive data structure into a flat list.
/// </summary>
/// <param name="input">The root elements of the recursive data structure.</param>
/// <param name="recursion">The function that gets the children of an element.</param>
/// <returns>Iterator that enumerates the tree structure in preorder.</returns>
public static IEnumerable<T> Flatten<T>(this IEnumerable<T> input, Func<T, IEnumerable<T>> recursion)
{
Stack<IEnumerator<T>> stack = new Stack<IEnumerator<T>>();
try {
stack.Push(input.GetEnumerator());
while (stack.Count > 0) {
while (stack.Peek().MoveNext()) {
T element = stack.Peek().Current;
yield return element;
IEnumerable<T> children = recursion(element);
if (children != null) {
stack.Push(children.GetEnumerator());
}
}
stack.Pop().Dispose();
}
} finally {
while (stack.Count > 0) {
stack.Pop().Dispose();
}
}
}
}
}
