Static library to redefine entrypoint

[Duncan Coutts]

On Fri, 2009-04-24 at 12:56 +0200, Philip K.F. Hölzenspies wrote:
> Dear GHCers,
> 
> I am trying to write a wrapper library for lab work to give to students.
> My problem is, that the libraries I use require initialization that I
> really want to hide from our students. The wrapper I'm writing is
> compiled to a static library and installed with cabal, so students can
> just "ghc --make" or "ghci" their sources. Here comes the problem: I
> want to define main and let students just define labMain as an entry
> point to their program.
> 
> How can I have my library use "labMain" without a definition? Keep in
> mind that I want to give them a cabalized library that they can just
> link to, so I can't give them a template file that they fill and compile
> together with my code. Is it at all possible to have "external"
> functions and letting the linker sort stuff out?

When I've set practicals like this I've just provided them with a 3 line
Main module that imports functions exported by the module(s) that the
students write. Eg I have them fill in Draw.lhs but tell them to compile
the thing using ghc --make Main.hs. I never found that this confused any
of them (indeed some were interested in looking at the code).

Duncan