How can I unbind all symbol definitions with a certain prefix?

Question

I'm changing up the API of my package pretty frequently, but company-mode pulls every defined symbol (as it should) in its completions. I don't want to accidentally use an unbound name, so how can I unbind all variables and functions that start with, say, my-package-? After this, I'll simply be able to load-file again.

Answer 1

Call unload-feature to undefine all symbols that were defined as part of loading an Elisp source or byte-compiled file. Make sure that your file ends by calling provide at the end. This assumes that you loaded the file with one of the load functions or via require, it won't undefined symbols defined by C-M-x (eval-defun) or similar mechanisms.

If you really want to unbind symbols based on their name rather than based on the package that defined them, you can use mapatoms to iterate over all symbols.

(mapatoms (lambda (symbol)
            (if (string-prefix-p "foo-" (symbol-name symbol))
                (unintern symbol))))

Answer 2

• Use makunbound to remove the use of a symbol as a dynamic variable (i.e., to void its symbol-value).

• Use fmakunbound to remove the use of a symbol as a function (i.e., to void its symbol-function).

• Use mapatoms to iterate over all symbols. Act on each whose symbol-name is matched by the particular prefix you are interested in: call both makunbound and fmakunbound on it.

• You do not need to unintern the symbol, unless you are also using completion against symbols themselves, and not just over their use as variables or functions. But if you do want to completely remove a symbol then use unintern.