Re: locate-library, the NOSUFFIX arg and a [PATCH]

[Stefan Monnier]

>>> It would be really great to ask with:
>>> (locate-library "libary" t '("/home/mon/fnd-lib") t)
>> 
>>> and get:
>>> => "/home/mon/fnd-lib/library.el.gz"
>> 
>> I don't follow you.  If you want that, then why do you specify a non-nil
>> value for NOSUFFIX??

> Look closely. The fourth arg of the second example is using the proposed
> SHOW-COMPRESSED.

That was definitely too subtle for me: Emacs-CVS's locate-library
already has a 4th argument, used for a completely different purpose.

> Which says, "Show me the file name sans extension unless library name
> is a compressed file in which case let me know by showing me
> the extension.

This said, I'm really lost as to why/when you'd want this kind of behavior.

> How exactly should one specify a library name for the LIBRARY arg to
> locate-library if this is not the same object(s) as a file name?

The argument provided to locate-library is the library name, so the
difference is pretty clear: "subr" is a library name and "/bar/subr.el"
is a file name.

>>> I asked to kill a library,
>> No, you didn't.  Check the docstring of locate-library:
>> "Show the precise file name of Emacs library LIBRARY."
>> I.e. it returns a file name, so you asked to "kill" a file name.
> Hrmmm. Precisely what is, "the precise file name of an Emacs library"?

You lost me here.

>> I have no idea what kind of "specification" you'd expect other than the
>> one you currently get from locate-library's docstring.
> Agreed. Hence the conundrum.

Even more lost.

>> although I'm not 100% positive it's the case because I don't really
>> know what it is you want (kill-new (locate-library "subr")) to do.

> This was provided as an example where I found the expected
> behavior surprising.

Unless you explain what other behavior you expect, that doesn't help us.

> A better example use-case for the proposed patch might be where one would
> like to generate a list from which one could inform/extend/override
> `emacs-lisp-file-regexp', `byte-compile-dest-file', `declare-function',
> `check-declare-directory', `byte-compiler-base-file-name', etc. to
> select/operate on a library per case based conditionals of the list elements.

I have no idea how you suggested change would help do any of this.

>> Depending on this question, we may be able to determine things like
>> whether you'd like (your-locate-library "foo.el" t) to return "/bar/foo"
>> or "/bar/foo.el".
> Exactly.

Now that was helpful.  I'm just wasting my time here.


        Stefan