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Re: check argument count in defcustom :safe?
From: |
Stefan Monnier |
Subject: |
Re: check argument count in defcustom :safe? |
Date: |
Sat, 11 Apr 2015 23:48:13 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) |
> :safe 'functionp)
FWIW, I think it makes absolutely no sense for :safe to be `functionp'.
This is just a gaping security hole. And checking the number of
arguments would make no difference in this respect.
> but I don't see any way to access the argument count from lisp. Am I
> missing something?
The number of arguments passed to a function is something that can be
easily checked by the function, but checking the number of arguments
accepted by a function is generally impossible (think of a function like
(lambda (&rest args)
(if (> (length args) (if (halting-p (car args)) 2 3))
(signal 'wrong-number-of-arguments 'foo (length args)))
...)
-- Stefan