Undo/Redo (with snapshots + one-way commands) #1900
Draft
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
…to execute() so that delta text insertions can execute the delta and then later adjust the composing region and have the whole thing considered to be a single transaction.
|
@matthew-carroll sorry for bothering with an update comment but have been waiting for undo/redo since a long time and just wanted to know whether it's being worked on or if there is a blocker |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Undo/Redo (with snapshots + one-way commands)
This is an undo/redo concept that's intended to avoid some of the complexities of the reversible command undo/redo version (#1881) by using
Editablestate snapshots, combined with a history of one-wayEditCommands.With this approach, when the user wants to undo a change, the
Editables are completely reverted to their most recent "snapshot" and then all historicalEditCommands are replayed, except the most recentEditCommand, thus achieving undo.This approach requires that
Editables be capable of providing some kind of immutable snapshot. It might be a Dart data structure, it might be JSON, etc. The format doesn't matter. EachEditableneeds to be able to provide some kind of snapshot, and then restore itself with that snapshot. This approach also re-runs a number of commands when undo'ing the previous command. This extra compute cost allows us to avoid the complexity of implementing reversible commands.