vim 1.14 source code undo.c [closed]

Question

Closed. This question is opinion-based. It is not currently accepting answers.

---

Want to improve this question? Update the question so it can be answered with facts and citations by editing this post.

Closed 8 years ago.

Improve this question

I am reading the code of vim 1.14 and I have some questions about undo.c.

I don't understand the implementation of the undo/redo operation, especially in the function u_undoredo().

I want to know why it uses the link list u_entry?

Answer 1

If you checkout the latest version of vim there is an explanation of vim's undo/redo implementation at the top of the undo.c file.

You can read it here.

Each u_entry list contains the information for one undo or redo.

A linked list would make sense for an undo/redo implementation to use since each entry only needs to reference the next or previous entry and can easily be added to efficiently. This is also why vim's undo history creates multiple branches of undo history. Beyond that, I'm not sure what your question is.