How does one tell when a command is executed from the minibuffer?

[Alan Mackenzie]

Hello, Emacs.

How does one tell when a command is executed from the minibuffer, e.g.

    M-: (foo)

, as contrasted with executing it from a file, e.g. by loading that
file, or with C-M-x or C-x C-e?

Something like (current-buffer) ought to do it, but `current-buffer'
"lies" when the current buffer is actually the minibuffer.

-- 
Alan Mackenzie (Nuremberg, Germany).