/// <summary>Returns new tree with added or updated value for specified key.</summary> /// <param name="key">Key</param> <param name="value">Value</param> /// <param name="updateValue">(optional) Delegate to calculate new value from and old and a new value.</param> /// <returns>New tree.</returns> public ImMap <TValue> AddOrUpdate(int key, TValue value, ImUpdateDelegate <TValue> updateValue) => AddOrUpdateImpl(key, value, false, updateValue);
private ImMap <TValue> AddOrUpdateImpl(int key, TValue value, bool updateOnly, ImUpdateDelegate <TValue> update)
{
return(Height == 0 ? // tree is empty
(updateOnly ? this : new ImMap <TValue>(key, value))
: (key == Key ? // actual update
new ImMap <TValue>(key, update == null ? value : update(Value, value), Left, Right)
: (key < Key // try update on left or right sub-tree
? new ImMap <TValue>(Key, Value, Left.AddOrUpdateImpl(key, value, updateOnly, update), Right)
: new ImMap <TValue>(Key, Value, Left, Right.AddOrUpdateImpl(key, value, updateOnly, update)))
.KeepBalance()));
}
