Adding System.FilePath

Bulat Ziganshin bulat.ziganshin at
Sun Mar 18 12:09:15 EDT 2007

Hello Jeffrey,

Sunday, March 18, 2007, 6:38:11 PM, you wrote:

>> try to compile base of ghc 6.6 using 6.4 compiler and vice versa. 6.8
>> is not yet finished, so i guess that differences between base 2.0 and
>> base 3.0 will be much larger that now

> That's inconvenient but not a fundamental problem. Say ghc-6.8 gets up
> to base-3.2 by the time 6.10 is released depending on base-4.0. Then
> someone wants to add System.ZOMGio to base. They add it to both
> base-3.3 and base-4.1. Someone who wants to use it needs to specify
> that they depend on base ">=3.3&&<4.0 || >=4.1", and can probably
> assume that >>=5.0 will also include it.

of course, this *can* be done. the problem is that it is hard to do, so
it is not done. and changes between base versions also include changed
interfaces, for example MArray class was changed in 6.6

>> > So, to solve the immediate problem you're complaining about, it might
>> > be more practical to pull the "bottom" (GHC/Prim*.hs) out of base into
>> > something like ghc-prim for ghc-6.8 rather than to prevent new modules
>> > from being added to the top. Then base can be refactored at a more
>> > leisurely pace.
>> look at :)

> You're depending on the existing base package from these files.

yes, but i tried to do it in that way that omitting Base dependency
will be easy. ghc.Prim, btw, is pseudo-module, whose "contents" are
generated by compiler automatically from primops.txt.pp

Core library is a first try to split GHC.* modules into ghc-specific
part (which is not limited to GHC.Prim) and the rest. Ultimately, Core
library should include compiler-specific code for several compilers
(ghc, nhc, hugs...) and additional code that simulates features
omitted in some compilers (arrays, for example). Core library should
export API which is the same for all compilers and compiler versions
and then Base should import Core and therefore become
compiler-independent. so, it just the same plan as your own

Best regards,
 Bulat                            mailto:Bulat.Ziganshin at

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