[gobolinux-users] Haskell Cabal build type?

[Isaac Dupree]

New versions of Happy and Alex require Cabal (The Haskell Cabal: Common 
Architecture for Building Applications and Libraries, 
<http://haskell.org/cabal/>) instead of 'configure'-type build. (and I 
need those new versions in order to develop GHC HEAD)  More applications 
written in Haskell are likely to use this in the future.  That's not so 
bad if we can just make a new recipe type.

Common Haskell libraries are being split up into separate pieces and 
less offered installed with newer releases of the GHC compiler.  We 
don't want to flood the /Programs namespace with all different little 
Haskell libraries; and each Cabal-based program-or-library declares 
which packages/modules/libraries it depends on, in a standard .cabal 
file.  We shouldn't try to manually keep intra-Haskell dependency 
listings in sync with these, either, as they are likely to change 
frequently.  Given how GHC normally works, it puts these in a system 
shared directory named by the GHC version (since e.g. GHC 6.6 and GHC 
6.6.1 -generated binaries are incompatible with each other).  So if an 
installed /Programs/GHC/6.6.1/ is used, should the libraries be 
installed somewhere inside /Programs/GHC/6.6.1/ perhaps?  I'm thinking 
Perl modules may be a similar existing issue; are they handled well, and 
if so, how? (I'm afraid it may be that they are handled poorly, from 
what I am hearing recently with Pidgin Unmanaged files, HAL failing to 
Compile... but I don't know.  Any information is better than none.)

Implementing something for Cabal might be easier once 'cabal-install' 
tool is released (it's a development version now).  Then again, if it 
will be used, I could try use that development version anyway.

I'm ignoring that Cabal also easily works with non-GHC compilers for 
now- that could make it even more complicated! (well, just that to 
install something Haskell, a compiler to install with/for would have to 
be chosen somehow. Already true for different versions of GHC.  Maybe a 
"preferred Haskell compiler for Compile" could be set somehow, by 
commandline, Settings/Compile/Compile.conf, a symlink... but it will be 
a while until other compilers than GHC are really usable. Which is 
partly why I'm ignoring it.)

What to do?

Isaac