# transform(updating:body:) Tracks the location of the selection throughout the mutation closure, updating the selection so it represents the same effective locations after the mutation. ``` mutating func transform(updating selection: inout AttributedTextSelection, body: (inout AttributedString) throws(E) -> Void) throws(E) where E : Error ``` ## Parameters `selection` The selection to track throughout the `body` closure. `body` A mutating operation, or set of operations, to perform on the value of `self`. The value of `self` is provided to the closure as an `inout AttributedString` that the closure should mutate directly. Do not capture the value of `self` in the provided closure - the closure should mutate the provided `inout` copy. ## Discussion> Note: If the mutation performed does not allow for tracking to succeed > (such as replacing the provided inout variable with an entirely > different `AttributedString`), the selection is reset to the fallback > location at the end of the text. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)