Packages with C code, and the packaging system

[lgautier]

Hi,

The package contains C code for a library (stored in deps/, as the documentation seems to suggest this directory to be the right location), and is in a Git repository (mirrorred on GitHub). In order to compile the C part, I was kinldly sent a nifty snippet of Julia code in a pull request (thanks Tom). That code is checking is the .so library file is around and if not call 'make' (I have a Makefile).

Beside the need to also add ".dll" to ".so" in order to accommodate Windows users (and this might challenge the view that users can become contributors to packages right away - getting a development environment with Windows is for the brave, as far as my experience with Python and R on that is concerned), I already added a comparison on mtime to assess whether a compilation is needed for the main C file but I am just aping what "make" is already doing (and quite not as well as "make" does it). That particular point is making me think that the current (Git) repository-only approach has one shortcoming: startup speed (and Julia does not need that).

Packages with C libraries shipped with the package could obviously call "make" each time the package is required/loaded, but this is looking like a rather heavy-weight requirement as a general solution as larger libraries with many C files might mean performance issues (even more if several packages are required by a Julia program - I am thinking of non-interactive usage, such as a webserver spawning a Julia for a given calculation, or distributed remote computing).

I understand that the packaging system is WIP. I am chiming so this point is not forgotten.

Best,

Laurent

[John Myles White]

We definitely need to start coming up with a strategy here. I believe that R's solution here is to pre-compile per-platform binaries on a special server and then ship those.

On a related note, I suspect that RMath should be moved into the Distributions package and out of Julia's deps directory at some point.

-- John

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[Avik Sengupta]

I was hoping the packaging system would provide a "after install" hook. That could be used to compile the native code. I've also wanted it to be able to show a message to the user, maybe informing them about optional dependencies. 

Regards

-

Avik

[Patrick O'Leary]

 You might take a look at refactoring the else branch of _resolve() to provide for that in base/pkg.jl. I think this is work just waiting for someone to do it.