Re: map, for-each

[Paul Emsley <paul.emsley@bioch.ox.ac.uk>]

On 26/08/10 12:17, Eric J. Van der Velden wrote:
> Hello,
>
> I don't understand what the manual says about when there are more then 
> two arguments to map or for-each.
>
> With two arguments, the last one must be a list, so OK is
>
> (for-each display '(1 3))
>
> But the following are ERR,
>
> (for-each display 1 3)
>
> (for-each display '(1 3) '(1 3))

The function, in this case `display', needs to be able to take 2 args, 
for display it's the variable and the port:

(for-each display '(1 3) (list (current-output-port) (current-output-port)))

also consider

(map + '(1 3) '(1 3))

Paul.