Re: Conditional binding and testing of `lexical-binding'

[Po Lu]

LdBeth <andpuke@foxmail.com> writes:

> (static-if (assoc 'lexical-binding (buffer-local-variables))
>    (provide 'lexical-binding))
>
> instead of doing `boundp' test.

I think it should be runtime, because transferring compiled code between
Emacs 23 and more recent versions is relatively common IME.

>> Is this the thing to do?  If not, what advice
>> do you have for adapting a library to use
>> lexical binding when available (Emacs 24+) but
>> to also work when it's unavailable (Emacs < 24)?

>> [The doc just tells you how to convert code to
>> use lexical binding.  I see nothing about how
>> to code compatibly for old and new Emacs.]

+1, there should at least be a paragraph or two in the Lisp reference
manual about that.

OTOH, I don't think there's much to be gained by using lexical binding
at all in code that's supposed to be compatible with versions of Emacs
without lexical binding.

It's not that important.