Use an append-only log to store "commands" #35
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Motivation
I never got
redoworking because the previous method was hard to test and reason about. This seems like a reasonable size refactor. See if it can help me to getredoout 🙂#34
Context
Currently, I am trying to implement
undoandredousing two mutable stacks. One stack keeps track of all the applied "commands", the other is used as a temp buffer.When an user action is committed, we would "push" it to the first stack. When the user undoes, we would "pop" the first stack (history stack), re-apply what is now on the first stack, and push the popped "command" onto the temp stack (redo stack).
For redo, we simply pop the redo stack, then apply the command and push it back to the history stack.
In my opinion, Mutating two logs is hard to reason about than just keeping track of the offsets of an append-only log.
What this PR does
This PR attempts to get rid of the two mutable stacks, and just use a single append-only log to store "commands" instead. We will use "offsets" of the log to implement the undo/redo logic.