Understanding eval-when-compile

[sergeyklay]

Hello,

I'd like to suggest cover eval-when-compile subject in terms of package development. Some topics are bellow:

• When a developer should use eval-when-compile despite the fact that at first glance everything works w/o eval-when-compile. I.e. some guidance and best practices
• eval-when-compile and tests. How it affects and helps. When this may leads to unexpected behavior. Please provide some examples
• Is the presence in a package defsubst, defmacro define-inline the reason to use eval-when-compile? Describe why.
• Provide please some anti-patterns or bad practices. When a developer shouldn't use eval-when-compile even this works
• eval-when-compile, autoloading, package building and distributing. How is this related?
• eval-and-compile, eval-when-compile, with-eval-after-load

Thank you

[alphapapa]

That's quite a list. How much of my final grade is this paper worth? :)

This topic is at the edge of my understanding. See https://lists.gnu.org/archive/html/emacs-devel/2020-04/msg00425.html. As I mentioned there, I think the Elisp manual's coverage of this topic should be improved, so I'd suggest filing an official bug report about that.

Beyond that, if you are willing to do the research, I'll be glad to publish your findings here. I publish information here as I come to understand it through my work on other projects.