Package manager - interacting with the compiler

[jdrewsen]

On Saturday, 10 December 2011 at 08:55:57 UTC, Jacob Carlborg 
wrote:
> I think I've come so far in my development of a package manager 
> that it's time to think how it should interact with the 
> compiler.
>
> Currently I see two use cases:
>
> 1. When the package manager installs (and builds) a package
>
> 2. When a user (developer) builds a project and want's to use 
> installed packages
>
> In the best of worlds the user wouldn't have to do anything and 
> it just works. The package manger needs to somehow pass import 
> paths to the compiler and libraries to link with.
>
> I'm not entirely sure what the best method to do this would be. 
> But I'm thinking that if the compiler could accept compiler 
> flags passed via environment variables use case 1 would be easy 
> to implement.
>
> For use case 2 it would be a bit more problematic. In this use 
> case the user would need to somehow tell the package manager 
> that I want to use these packages, something like:
>
> // project.obspec
> orb "foo"
> orb "bar"
>
> $ orb use project.obspec
>
> or for single packages
>
> $ orb use foobar
> $ dmd project.d
>
> If environment variables are used in this case, then the 
> package manager would need a shell script wrapper, the same way 
> as DVM does it, to be able to set environment variables for the 
> parent (the shell). The reason for this is that a child process 
> (the package manager) can't set environment variables for the 
> parent process (the shell). This complicates the implementation 
> and installation of the package manager and requires different 
> implementations for Posix and Windows.
>
> Another idea would be to manipulate the dmd.conf/sc.ini file 
> but that seems to be quite complicated and messy. On the other 
> hand, this wouldn't require any changes to the compiler.
>
> Any other ideas?
>
> https://github.com/jacob-carlborg/orbit/wiki/Orbit-Package-Manager-for-D
> https://github.com/jacob-carlborg/orbit

For use case 1 the package manager could just as well call dmd 
directly with the correct flags ie. no need for using environment 
variables. Use case 2 does not belong to a package manager in my 
opinion. It is the job of a build tool to configure packages for 
a project. What would be nice to have support for using packages 
without a build tool. Maybe something like what pkg-config 
provides:

dmd -ofhello `orb -lib foo` hello.d   where "org -lib foo" 
returns the flags to use the foo package.

/Jonas