Re: Some vc-dispatcher nitpicks

[John Paul Wallington <jpw@pobox.com>]

On 16 May 2008, at 23:08, Eric S. Raymond wrote:

> John Paul Wallington <jpw@pobox.com>:
>> `gensym' is a function rather than a macro and it apparently doesn't
>> have a corresponding compiler macro.  Use or loading of cl at  
>> runtime by
>> packages that are installed in the Emacs sources is verboten.
>
> Hmmm...can anyone explain why that is?  It should be docunted  
> somewhere.

It's policy.  It is documented in the elisp manual; see (elisp) Coding  
Conventions:

    * Please don't require the `cl' package of Common Lisp extensions at
      run time.  Use of this package is optional, and it is not part of
      the standard Emacs namespace.  If your package loads `cl' at run
      time, that could cause name clashes for users who don't use that
      package.

      However, there is no problem with using the `cl' package at
      compile time, with `(eval-when-compile (require 'cl))'.  That's
      sufficient for using the macros in the `cl' package, because the
      compiler expands them before generating the byte-code.

>> Is it okay to install the following patch?
>
> Yes, that looks good.  Thanks.  It might be possible to remove the  
> eval-compile
> of cl, as well, once you've done this; you'd be doing me a favor if  
> you checked.

Checked it.  Doesn't work, though I mistakenly thought it did.  O_o