Advance notice that I'd like to make Cabal depend on parsec

[Simon Peyton-Jones]

Yes I think that'd be a great plan.  It's bizarre that GHC depends on *all* of Cabal, but only uses a tiny part of it (more or less the Package data type I think).

Simon

|  -----Original Message-----
|  From: cabal-devel-bounces at haskell.org [mailto:cabal-devel-bounces at haskell.org]
|  On Behalf Of Administrator
|  Sent: 14 March 2013 15:23
|  To: Duncan Coutts
|  Cc: Lentczner; cabal-devel; Haskell Libraries; ghc-devs at haskell.org
|  Subject: Re: Advance notice that I'd like to make Cabal depend on parsec
|  
|  This GHC dependency on Cabal is putting a rather troubling constraint
|  in Cabal's evolution, which in my opinion is a serious problem. When I
|  first took a look at the dependencies between GHC and Cabal I found it
|  a bit strange that GHC would depend on Cabal as I would expect GHC to
|  be as low in the dependency tree as possible to avoid exactly these
|  kinds of problems.
|  
|  These GHC dependencies on Cabal are in fact small (see
|  http://hackage.haskell.org/trac/ghc/attachment/ticket/7740/ghc-2.png
|  for a summary) and with a little bit of refactoring it would be
|  possible to split these dependencies into a very small shared package
|  with minimal or no further dependencies. This would liberate Cabal to
|  make the necessary refactoring.
|  
|  IMHO, the addition of these new dependencies to Cabal should go
|  together with splitting the GHC-Cabal shared dependencies into a
|  separate package so that there would be no additional coordination
|  needed from then on between these two development efforts (except when
|  dealing with this new package).
|  
|  
|  On Thu, Mar 14, 2013 at 12:12 PM, Duncan Coutts
|  <duncan.coutts at googlemail.com> wrote:
|  > On Thu, 2013-03-14 at 16:06 +0100, Gregory Collins wrote:
|  >> On Thu, Mar 14, 2013 at 3:53 PM, Duncan Coutts
|  <duncan.coutts at googlemail.com
|  >> > wrote:
|  >>
|  >> > Hi folks,
|  >> >
|  >> > I want to give you advance notice that I would like to make Cabal depend
|  >> > on parsec. The implication is that GHC would therefore depend on parsec
|  >> > and thus it would become a core package, rather than just a HP package.
|  >> > So this would affect both GHC and the HP, though I hope not too much.
|  >>
|  >>
|  >> +1 from me, although the amount of potential knock-on work might be
|  >> discouraging. The current cabal-install bootstrap process (which is
|  >> currently pretty easy and is necessary at times) will get a bunch more deps
|  >> as a result of this change, no?
|  >
|  > Yes it will, but given that we do have a script it's not too bad I
|  > think. And overall I think its worth it to have the better error
|  > messages, performance and memory use. Do you have any idea how slow it
|  > is to parse all the .cabal files on hackage, and how much memory that
|  > takes? You'd be horrified :-)
|  >
|  > Duncan
|  >
|  >
|  > _______________________________________________
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