Re: Re: [cclan-list] Order of *CENTRAL-REGISTRY* traversal

On Wed, 7 Dec 2005, Max-Gerd Retzlaff wrote:

>   | (push #p"lispdir:systems;" asdf:*central-registry*)
>   | (push #p"sbcldir:systems;" asdf:*central-registry*)
>   | (push #p"coding:systems;" asdf:*central-registry*)

Are you intentionally overriding the SBCL-provided directories
in *central-registry*?

In any case it seems to me that changing the way *central-registry*
works is a bad idea and a good way to increase the amount of pain
in the world.

So, I revise my position completely (always good for a laugh):

  1) Keep *central-registry* and *module-provider-functions* traversal
     as is.

  2) Make ASDF add its provider function the _end_ of *m-p-f*, so that ASDF
     modules will not accidentally override contribs. (Not all contribs
     have .asd files.)

  3) Add sysdef-contrib-search-function to the head of
     *system-definition-search-functions* that looks in
     (MERGE-PATHNAMES "systems/" (TRUENAME (POSIX-GETENV "SBCL_HOME")))
     -- and remove the corresponding entry from *central-registry*.
     This is also needed with 2) for consistency between (OOS 'LOAD-OP X)
     and (REQUIRE X).

  4) Document all of this properly.

End result: current overriding behaviour for user-space components, but 
overriding a contrib takes extra work: you need to add new functions to 
*m-p-f* and *s-d-s-f* to do that, instead of just pushing on 
*central-registry*.

How does that sound?

Cheers,

  -- Nikodemus              Schemer: "Buddha is small, clean, and serious."
                   Lispnik: "Buddha is big, has hairy armpits, and laughs."


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