Question

Suppose I have a function (foo) defined as (defun foo () (read-from-minibuffer "What? ")). I cannot change the definition, but I’d like to wrap it around a macro, or another function, so to avoid having to manually give any value.

Unfortunately the following solutions don’t work, as (exit-minibuffer) is only called after leaving the minibuffer, so I was wondering if you know of something.

(defmacro return-an-empty-string (&rest code) `(progn ,@code (exit-minibuffer)))
(defun return-an-empty-string (function) (funcall function) (exit-minibuffer))

Thanks!

Answer 1

You can temporarily make read-from-minibuffer into a do-nothing function:

(require 'cl)
(defmacro preempt-minibuffer (&rest body)
  `(flet ((read-from-minibuffer (&rest ignore)))
     ,@body))