[Agda] Lightweight dependency management using make

[Alan Jeffrey]

Hi everyone,

I just created a new repository at:

   https://github.com/agda/agda-makefile

This is a bash at dependency management for Agda projects, since I'm 
starting to build projects with common libraries.

The dependency management systems I'm familiar with are cabal and maven, 
both of which are quite tightly integrated with particular languages 
(Haskell and Java respectively). I could try hacking away at cabal to 
make it Agda-aware, but this sounds like hard work to me! (AFAIK the 
state of play on Agdaizing cabal is still as discussed here: 
http://thread.gmane.org/gmane.comp.lang.agda/1055 but it could be that 
more has happened since, although the program notes for AIMXII 
http://wiki.portal.chalmers.se/agda/pmwiki.php?n=AIMXII.Notes suggest 
not :-)

So I hacked out a quick-and-dirty (or "lightweight" if you prefer) 
makefile that uses curl to download dependencies. The core of it is to 
allow makefiles to declare dependencies, for example:

   dependencies = bar baz

and declare the tarball URIs for those dependencies:

   bar = http://example.com/bar.tgz
   baz = http://example.com/bar.tgz

from which a target "install-dependencies" downloads, unpacks, and 
installs the dependencies. There's also some standard targets to 
typecheck or generate HTML, for example:

   install-agda: $(agdadir)/Foo.agdai
   install-html: $(htmldir)/Foo.html
   install: install-dependencies install-agda install-html

You can see it in action in the project 
https://github.com/agda/agda-text-xml which depends on 
https://github.com/agda/agda-web-uri (currently these are skeleton 
projects, but will be filled in real soon now).

Thoughts?

Alan.