Re: eval-when-compile help?

[Dmitry Gutov <dgutov@yandex.ru>]

On 05.10.2021 18:05, Stefan Monnier wrote:
>> So I suppose this is the final form:
>>
>> (eval-and-compile
>>    (when (version< emacs-version "28")
>>      (require 'eieio)
>>
>>      (with-no-warnings
>>        (defclass xref-location () ()
>>          :documentation "(Obsolete) location represents a position in a file
>>         or buffer."))))
> 
> Better use `with-suppressed-warnings` than `with-no-warnings` (or at
> least add a comment explaining what warning you're silencing).

with-suppressed-warnings was added in 27, and xref.el is still targeting 
26+. A comment sounds fine.

> BTW, maybe a better option is to use a macro like:
> 
>      (defmacro if-when-compile (test then else)
>        (if (eval test t) then else))
> 
> and then do
> 
>      (if-when-compile (version< emacs-version "28")
>          (progn
>            (require 'eieio)
>            
>            (defclass xref-location () ()
>              :documentation
>              "(Obsolete) location represents a position in a file or buffer.")))

That gives me

   Wrong number of arguments: (3 . 3), 2

What would I put in the 'else' branch anyway?