Re: Removing unloaded functions from auto-mode-alist.

[David Kastrup <dak@gnu.org>]

Lute Kamstra <Lute.Kamstra.lists@xs4all.nl> writes:

> David Kastrup <dak@gnu.org> writes:
>
>> The function that _clearly_ should trigger/use the recorded
>> information, however, is "require".
>
> Agreed.
>
>> I don't think we need to make (load "filename") (unload-feature
>>'filename) do anything sensible (and indeed it is legal to load the
>>same file several times in succession), but it seems desirable to
>>have (require 'filename) (unload-feature 'filename) form a proper
>>pair.
>
> I'm not sure if it's the best solution not to let (load "filename")
> record autoloads.

Well, the idea explored a bit later later was that "load" will record
autoloads, but not do anything with them by itself, instead letting
"provide" handle it.

> But letting only (require 'filename) record autoloads would be a big
> improvement.  My guess is that the vast majority of files get loaded
> by do_autoload and Frequire.  Furthermore, it seems quite easy to
> implement the recording of autoloads in Frequire.  I'll give it a
> try and experiment with it for a while...
>
>> Unfortunately, this does not work well with the site-lisp.el
>> construct
>> (mapc 'load-file (directory-files "site-start.d" t ".el\\'"))
>>
>> So a better expedient would be to have
>> (provide 'xxx)
>>
>> turn on the necessary action at the end of the current load file in
>> case that the feature is provided the first time.
>>
>> This should be a pretty reliable way to do the recordings for files
>> that are connected with a "feature".
>
> I'm not familiar with this.  Could you elaborate?

Many Emacs installations have a site-lisp/site-start.d directory.  If
you want some code executed automatically (usually a bunch of
autoloads), then you'll drop the .el file in that directory.

> When is this used?  Does it load files that define functions that
> replace autoloads?

I guess the most common case would be loading files that _place_
autoloads and add stuff to hook functions.

And it usually is a bunch of stuff that the system administrator
thought good for you.  For example, if you install a prepackaged
foobar package from your favorite distribution, then this will drop
foobar.el into site-lisp/site-start.d/ and foobar.el will then setup
the package foobar with autoloads and similar.

If the wisdom of the system provider did not match your personal
tastes, being able to (unload-feature 'foobar) would be definitely
nice.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum