public ImmutableNode <TKey, TValue> AddChild(ImmutableNode <TKey, TValue> newChild)
{
// copy the existing children to a new array, and append the new one.
ImmutableNode <TKey, TValue>[] newChildNodes = new ImmutableNode <TKey, TValue> [this.childNodes.Length + 1];
Array.Copy(this.childNodes, newChildNodes, this.childNodes.Length);
newChildNodes[this.childNodes.Length] = newChild;
// create new node with new child node.
return(this.CreateClone(newChildNodes));
}
public ImmutableNode <TKey, TValue> ReplaceChild(ImmutableNode <TKey, TValue> childToReplace, ImmutableNode <TKey, TValue> newChild)
{
if (object.ReferenceEquals(childToReplace, newChild))
{
return(this); // nothing to do
}
if (!childToReplace.TryGetKey(out var childToReplaceKey))
{
throw new ArgumentException("child node must have a key", nameof(childToReplace));
}
if (!newChild.TryGetKey(out var newChildKey))
{
throw new ArgumentException("child node must have a key", nameof(newChild));
}
if (!EqualityComparer <TKey> .Default.Equals(childToReplaceKey, newChildKey))
{
throw new InvalidOperationException($"Key of child to replace (key='{childToReplaceKey}') and new child (key='{newChildKey}') must be equal");
}
var newNodesChildren = new ImmutableNode <TKey, TValue> [this.childNodes.Length];
bool hasReplaced = false;
for (int i = 0; i < this.childNodes.Length; i++)
{
if (this.childNodes[i].Equals(childToReplace))
{
newNodesChildren[i] = newChild;
hasReplaced = true;
}
else
{
newNodesChildren[i] = this.childNodes[i];
}
}
if (hasReplaced)
{
return(this.CreateClone(newNodesChildren));
}
throw new InvalidOperationException($"The node (id={newChildKey}) doesn't substutite any of the existing child nodes");
}
public ImmutableNode <TKey, TValue> RemoveChild(ImmutableNode <TKey, TValue> child)
{
return(this.CreateClone(this.ChildNodes.Except(new[] { child }).ToArray()));
}
