iter.go raw

   1  // Copyright 2024 The Go Authors. All rights reserved.
   2  // Use of this source code is governed by a BSD-style
   3  // license that can be found in the LICENSE file.
   4  
   5  //go:build go1.23
   6  
   7  package html
   8  
   9  import "iter"
  10  
  11  // Ancestors returns an iterator over the ancestors of n, starting with n.Parent.
  12  //
  13  // Mutating a Node or its parents while iterating may have unexpected results.
  14  func (n *Node) Ancestors() iter.Seq[*Node] {
  15  	_ = n.Parent // eager nil check
  16  
  17  	return func(yield func(*Node) bool) {
  18  		for p := n.Parent; p != nil && yield(p); p = p.Parent {
  19  		}
  20  	}
  21  }
  22  
  23  // ChildNodes returns an iterator over the immediate children of n,
  24  // starting with n.FirstChild.
  25  //
  26  // Mutating a Node or its children while iterating may have unexpected results.
  27  func (n *Node) ChildNodes() iter.Seq[*Node] {
  28  	_ = n.FirstChild // eager nil check
  29  
  30  	return func(yield func(*Node) bool) {
  31  		for c := n.FirstChild; c != nil && yield(c); c = c.NextSibling {
  32  		}
  33  	}
  34  
  35  }
  36  
  37  // Descendants returns an iterator over all nodes recursively beneath
  38  // n, excluding n itself. Nodes are visited in depth-first preorder.
  39  //
  40  // Mutating a Node or its descendants while iterating may have unexpected results.
  41  func (n *Node) Descendants() iter.Seq[*Node] {
  42  	_ = n.FirstChild // eager nil check
  43  
  44  	return func(yield func(*Node) bool) {
  45  		n.descendants(yield)
  46  	}
  47  }
  48  
  49  func (n *Node) descendants(yield func(*Node) bool) bool {
  50  	for c := range n.ChildNodes() {
  51  		if !yield(c) || !c.descendants(yield) {
  52  			return false
  53  		}
  54  	}
  55  	return true
  56  }
  57