:require dependency

[Robert Goldman]

On 6/25/15 Jun 25 -4:20 PM, Didier Verna wrote:
> 
>   Hello,
> 
> can somebody explain to me what is the :require dependency specification,
> and how it compares to just a simple-component-name ?
> 
> Thanks.
> 

According to the manual REQUIRE-SYSTEM is "... a version of
@code{load-system} that skips trying to update systems that are already
loaded."

There is no REQUIRE-OP.

There is a REQUIRE-SYSTEM which is a system whose loading is handled by
REQUIRE instead of native ASDF.

When you make a :REQUIRE dependency, the corresponding system is made
into a REQUIRE-SYSTEM so that when you try to operate on it, the
operations are handled by REQUIRE instead of ASDF proper.

This might be useful, e.g., on ACL, which has many bundled modules which
are loaded by REQUIRE.

I'm not sure there is a common implementation-independent use case,
since people aren't distributing a lot of code to be loaded with
REQUIRE, AFAICT.

Hope that helps.  Sorry for the late answer: we've been grappling with
some knotty bugs on Windows.

Cheers,
r