Re: [PATCH] Proposal: implement feature-dependent-op

Richard M Kreuter <[email protected]> writes:

> Christophe Rhodes <[email protected]> writes:
>
>> It's probably undocumented, but you can actually do this at the
>> moment:
>>   :in-order-to ((load-op (feature :ppc) (feature :darwin))
>>                 (compile-op (feature :ppc) (feature :darwin)))
>> in a component's dependencies.
>
> The functionality I propose makes the traverse prune components
> depending on features.  

OK, but is this something that should be encouraged?  I mean, I can
see why you wouldn't want to compile-op something that you don't have
the feature for, but you probably still want to tarball-op it.

> The ":in-order-to ((... (feature ...)))"
> notation expresses a different modality: the absence of the feature
> makes TRAVERSE signal an error.
>
> CL-USER> (find :f1 *features*)
> NIL
> CL-USER> (defsystem my-sys-2
> 	   :pathname "."
> 	   :components ((:file "file1"
> 			       :in-order-to ((compile-op (feature :f1))))))
> #<SYSTEM "my-sys-2" {507C8891}>
> CL-USER> (asdf:oos 'asdf:compile-op 'my-sys-2)
> component :F1 not found, required by #<CL-SOURCE-FILE "file1" {50CCBE61}>
>    [Condition of type MISSING-DEPENDENCY]

Right, though there are the probably also-undocumented features
:if-component-dep-fails :ignore/:try-next which let you write
conditionally-compiled code while still considering the component part
of the system.

> The interface to the desired functionality could be provided by adding
> syntax to :in-order-to, I guess.

I suppose I'm asking why you desire this functionality, then.

Cheers,

Christophe

-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys - and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV