How can I refactor C++ source code using emacs?
I'm interested mostly in C++ and method/class name/signature automatic changes.
In recent Emacs versions (24), Semantic is able to this.
- Possibly activate semantic mode M-x semantic-mode RET.
- Bring up the Symref buffer with C-c , g.
- Press C-c C-e to open all references.
- Rename with R.
If you can program in elisp, you can look to combination of cedet + srecode from CEDET libraries - it provide all instruments for this task - find callers of functions, get signature, etc. But you need to create refactory tool yourself, using these instruments
I do this a lot, so I'm axiously awaiting other replies too.
The only tricks I know are really basic. Here are my best friends in Emacs when refactoring code:
M-x query-replace
This allows you to do a global search and replace. You'll be doing this a ton when you move methods and commonly-accessed data to other classes or namespaces.
C-x 3
This gives you a display with two buffers side-by side. You can then proceed to load different files in them, and move your cursor from one to the other with C-x o. This is pretty basic stuff, but I mention it because of how powerful it makes the next one...
C-x (
(type any amount of stuff and/or emacs commands here)
C-x )
This is how you define a macro in emacs. Any time you find yourself needing to do the same thing over and over to a bunch of code (and it is too complex for query-replace), this is a lifesaver. If you mess up, you can hit C-g to stop the macro definition, and then undo (C-_) until you are back to where you started. The keys to invoke the macro are C-x e. If you want to do it a bunch of times, you can hit Esc and type in a number first. Eg: Esc 100 C-x e will try to invoke your macro 100 times.
(Note: On Windows you can get "Meta" by hitting the Esc key, or holding down Alt).
For somewhere in between refactoring tools and simple regex, since Emacs 22 you can embed arbitrary elisp expressions in your replacement text, which allows you to do incredibly powerful text manipulation. Steve Yegge wrote a good article on this a while ago.
The current (2022) state of the art is, I would say, using emacs lsp-mode with a suitable language server.
With the clangd or ccls, which provide the "language server protocol" (lsp) and connect to lsp-mode, you can refactor names with:
M-x lsp-rename
To simplify this setup, I'd recommend using Spacemacs with c-c++ and lsp layers (and using clangd).