[cffi-devel] proposed patch for clisp

[Daniel Herring]

On Fri, 2 Jan 2009, Luís Oliveira wrote:

> On Fri, Jan 2, 2009 at 5:26 AM, Daniel Herring <dherring at tentpost.com> wrote:
>> FFI is an optional clisp feature.  Thus I propose adding it to CFFI's list
>> of dependencies.
> [...]
>> +  :depends-on (alexandria trivial-features babel #+clisp ffi)
> [...]
>
> How about a #-ffi (error "CFFI requires a version of CLISP compiled
> with the FFI module.") in src/cffi-clisp.lisp? Or something like that
> in cffi.asd. What'd be the advantage of putting that in the ASD file?

I'm trying to write a tool to load a collection of ASDF packages, skipping 
those which won't work on a given implementation/platform.  With ffi in 
the ASD defsystem, I can query asdf:component-depends-on before loading or 
handle ASDF:MISSING-DEPENDENCY at load time.

An ad-hoc error requires me to know in advance not to load CFFI, but it 
does provide a custom error message.

- Daniel

P.S.  I think its an ASDF defect that there is no mechanism for separately 
specifying dependencies on other packages, *features*, and arbitrary 
predicate functions.  With optional documentation for each.