Re: Proper use of function form

[Tim Johnson <tim@akwebsoft.com>]

On 4/26/20 4:05 PM, Michael Heerdegen wrote:
> Tim Johnson <tim@akwebsoft.com> writes:
>
>> Would it be better to change (nth (+ ndx 1) mylist) to
>> (function (nth > (+ ndx 1) mylist)) ?
> No:
>
> "Like `quote', but preferred for objects which are functions.
> In byte compilation, `function' causes its argument to be handled by
> the byte compiler.  `quote' cannot do that."
>
> "(nth > (+ ndx 1) mylist)" is not a function - it is an
> expression that will evaluate to a function.  Since `function' acts like
> `quote', using this special form would prevent that evaluation, so it
> won't work.
>
> The underlying problem is that your expression is evaluated at
> run-time.  Useful for the compiler would only be a function name known
> at compile time.  If you know the function name at compile time, you
> don't want to eval it at run time, so you want to `quote' anyway.
>
> So what can you do?  Since we don't have a multiple-define-key function,
> you can just stay with your loop as is - there is nothing wrong with
> that, but you'll not get compiler warnings like "unknown function".  You
> can also use a macro that would expand to a sequence of `define-key'
> calls at compile time.  Or construct the whole keymap at compile time,
> using list functions (or `backquote').  But that's rather uncommon.
> Most people just write the key definition calls out or just don't care -
> even in the Emacs sources.

Thanks Michael. I will leave will enough alone.

cheers

-- 
Tim
tj49.com