Re: Lisp Api and backward compatibility

[Eli Zaretskii]

> From: Sameer Rahmani <address@hidden>
> Date: Fri, 12 Apr 2019 21:09:54 +0100
> 
> What should i consider before changing the signature of a function which 
> is part of the public api of a library ? should I add the new argument 
> as the last argument ? what do we usually do for backward compatibility ?

It is best not to make incompatible changes, if that's reasonably
possible.  E.g., if there is a manifest variable that controls the
behavior, it is better to introduce an additional value of that
variable than completely change the API.

If it isn't reasonable to keep backward compatibility, then some kind
of optional behavior that defaults to the previous one is the next
best choice.

For more specific responses, please tell more about the API you think
is in need of change, and why.

Thanks.