Passing function as argument

[Gideon Kay]

I am trying to pass a function name as an argument and am getting an error
regarding "global function".

The function is for example:

(defun is-also-true (m)
(every #'its-true (produce-result-column #'m *three*)))

where m is a function name.

Any ideas?

Thanks

Gideon
gideo...@virgin.net

[Pierre R. Mai]

"Gideon Kay" <g...@virgin.net> writes:

> I am trying to pass a function name as an argument and am getting an error
> regarding "global function".
>
> The function is for example:
>
> (defun is-also-true (m)
> (every #'its-true (produce-result-column #'m *three*)))
>
> where m is a function name.

You are confused as to the use of #' or (function x). It is used to
"convert" a name that is lexically or globally apparent into the
function value of that name.

You are just passing on the value of m (which might be the name of a
global function, or a (possibly lexical) function itself) that is
passed into your function. So there is no need to "convert" again:

(defun is-also-true (m)
(every #'its-true (produce-result-column m *three*)))

Then you can call is-also-true with either a symbol that denotes a
global function, or with a proper function, as usual:

(defun use-it ()
(flet ((mypred (x) (> x 10)))
(is-also-true 'evenp)
(is-also-true #'evenp)
(is-also-tue #'mypred)))

Regs, Pierre.

--
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"One smaller motivation which, in part, stems from altruism is Microsoft-
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