ghc-pkg, recompilation check

[Simon Marlow]

On 06 June 2005 15:42, Serge D. Mechveliani wrote:

> And in  6.4,   make dm
> reports
> ...
> " Reading package info from stdin... done.
>   ghc-pkg: invalid package identifier:
> "

The syntax of package descriptions has changed.  Documentation for the
new format is here: 

http://www.haskell.org/ghc/docs/latest/html/users_guide/packages.html#in
stalled-pkg-info

> Packages always were difficult. And in 6.4 they are changed again ...

I'd urge you to look at using Cabal for your library, I think it'll
simplify things for you a lot.  In particular, you won't have to deal
with ghc-pkg and you won't have to write any Makefiles.  Cabal is
specifically designed to make life easier for people like you!

I know changes are painful, but in this case they weren't gratuitous.
All the changes were to support Cabal, and we believe this is the right
direction to go.  If it all pans out, we won't need to make any big
changes again in the future.

> Question 2: recompilation
> -------------------------
> 
> Why does it recompile both modules when after the first  make dm
> we remove the  .a  library and repeat                    make dm
> ?
> This recompilation bites when there are many modules.

Unfortunately your use of -ddump-hi-diffs has forced recompilation.
This is a bug: we changed it so that all -ddump-* flags forced
recompilation because  in most cases some intermediate output has been
requested.  However, -ddump-hi-diffs should be an exception.  Thanks for
the report - just turn off -ddump-hi-diffs.

Cheers,
	Simon