Re: [Caml-list] Conditional BuildDepends in OASIS

[Anil Madhavapeddy <anil@recoil.org>]

On 26 Oct 2012, at 10:56, Dario Teixeira <darioteixeira@yahoo.com> wrote:
> 
> That would be a satisfactory solution.  I did run into a different problem, though.
> I told OASIS that "pgocaml.batteries" and "pgocaml.extlib" should have "pgocaml"
> as their findlib parent (fragment below).  Unfortunately, OASIS complains that
> library "pgocaml" does not exist.  How would I tell OASIS that "pgocaml" is a
> dummy library?
> 
> Flag "batteries"
>   Description: Use Batteries
>   Default: true
> 
> Library "pgocaml_batteries"
>   Build$:               flag(batteries)
>   Install$:             flag(batteries)
>   Path:                 src
>   Modules:              PGOCaml
>   BuildDepends:         calendar, batteries
>   ByteOpt+:             -ppopt -DUSE_BATTERIES
>   NativeOpt+:           -ppopt -DUSE_BATTERIES
>   FindlibParent:        pgocaml
>   Findlibname:          batteries

You could just put a dummy library in place (which shouldn't be used by anything
since you don't have to mark a dependency of a findlib child on the parent
library, as far as I understand it.

However, is there a common subset of your code that is portable without either
Batteries or Extlib?  Factoring that out into a core library that both of the
other ones depend on would make future ports (e.g., to Core or Lwt) easier.

Of course, this is easier said than done when dealing with replacement standard
libraries which redefine very common library functions!  It's a lot easier when
factoring over I/O libraries like Lwt vs Async where a straightforward functor
abstraction exists.

-anil