In one of my packages, I use a loop with completing-read to query the user for a list of words. Inside the prompt, I'd like to bind DEL to a different command.
How can I achieve that?
The solution also needs to work with ido-completing-read (possibly with small modifications of course).
There are of course keymaps you can bind stuff to. For example you could temporarily merge minibuffer-local-filename-completion-map with your extra keys. From the documentation:
Local keymap for minibuffer input with completion for filenames.
Gets combined either with `minibuffer-local-completion-map' or
with `minibuffer-local-must-match-map'.
Just have your command bind the key you want in the appropriate minibuffer keymap, and then unbind it there when the command is done.
[You do not need to merge keymaps. You just need to bind the key in a map that is already being used (whether it was merged or not).]
The minibuffer keymaps that involve completion (depending on your Emacs version):
minibuffer-local-completion-map
minibuffer-local-filename-completion-map
minibuffer-local-filename-must-match-map
minibuffer-local-must-match-filename-map
minibuffer-local-must-match-map
