Re-jig done and committed.
On 2013-07-25 04:06, Simon Peyton-Jones wrote:
Hs-boot files tend to get in the way of optimisation. Moreover,
sometimes they are truly necessary, and if there are un-necessary ones
that can greatly complicate adding necessary ones. There are already
LOTS of data types declared as instances of Typeable at the place that
Typeable class is defined; no harm in one more.
So I'd really prefer the re-jig if that's ok
Simon
| -----Original Message-----
| From: Richard Eisenberg [mailto:e...@cis.upenn.edu]
| Sent: 24 July 2013 22:37
| To: Simon Peyton-Jones
| Cc: ghc-devs@haskell.org
| Subject: Re: [commit: base] master: Implement "TypeLevelReasoning"
proposal
| at wiki:TypeLevelReasoning (365b9d8)
|
| I agree that hs-boot files are a little inelegant, but is there a
bigger problem with
| them? I consider instances to be more tied to a datatype definition
than the class
| definition. It may be possible (I think it is) to avoid the
Proxy.hs-boot and
| Equality.hs-boot files if we scatter their instances across the
modules. But, then
| the "definition" of these types would be spread across a large
surface area. To me,
| that makes the types harder to update and perhaps harder to
understand (though
| haddock does a nice job of collecting all the instance declarations
together).
|
| So, my thought is that the mechanism of hs-boot files may be a
little ugly, but it
| makes the code (that is, the collection of instances) easier to
consider as a whole
| and easier to update. That tradeoff seems worthwhile.
|
| That all said, if you (or others) feel strongly about it, I can
rejigger it.
|
| Richard
|
| On Jul 24, 2013, at 3:14 PM, Simon Peyton-Jones wrote:
|
| > Richard I am deeply suspicious of all these hs-boot files.
| >
| > Instances should preferably go EITHER with the data type
declaration OR with
| the class declaration.
| >
| > In the case of Proxy, for example, why can't the Typeable
instance for Proxy go
| in Data.Typeable.Internals? (And perhaps similarly for other
instances.)
| >
| > Simon
| >
| > | -----Original Message-----
| > | From: ghc-commits [mailto:ghc-commits-boun...@haskell.org] On
Behalf Of
| > | Richard Eisenberg
| > | Sent: 24 July 2013 12:41
| > | To: ghc-comm...@haskell.org
| > | Subject: [commit: base] master: Implement "TypeLevelReasoning"
proposal
| at
| > | wiki:TypeLevelReasoning (365b9d8)
| > |
| > | Repository : http://darcs.haskell.org/ghc.git/
| > |
| > | On branch : master
| > |
| > |
|
http://hackage.haskell.org/trac/ghc/changeset/365b9d86d195dc483610a68836b4
| > | 063656602244
| > |
| > |
>---------------------------------------------------------------
| > |
| > | commit 365b9d86d195dc483610a68836b4063656602244
| > | Author: Richard Eisenberg <e...@cis.upenn.edu>
| > | Date: Wed Jul 24 12:38:50 2013 +0100
| > |
| > | Implement "TypeLevelReasoning" proposal at
wiki:TypeLevelReasoning
| > |
| > | This commit includes a propositional equality (:=:) in
Data.Type.Equality,
| > | a Proxy type in Data.Proxy, and has updates to Typeable.
| > |
| > | There is an unfortunate number of hs-boot files necessary,
but that
| > | seems cleaner than moving Typeable instances around
willy-nilly.
| > |
| > | Data/Data.hs | 2 +-
| > | Data/Proxy.hs | 129
| > | ++++++++++++++++++++++++++++++++++++++++
| > | Data/Proxy.hs-boot | 5 ++
| > | Data/Type/Equality.hs | 99
| > | ++++++++++++++++++++++++++++++
| > | Data/Type/Equality.hs-boot | 6 ++
| > | Data/Typeable.hs | 42 +++++++------
| > | Data/Typeable/Internal.hs | 5 +-
| > | Data/Typeable/Internal.hs-boot | 3 +-
| > | base.cabal | 2 +
| > | 9 files changed, 269 insertions(+), 24 deletions(-)
| > |
| > |
| > | Diff suppressed because of size. To see it, use:
| > |
| > | git show 365b9d86d195dc483610a68836b4063656602244
| > |
| > | _______________________________________________
| > | ghc-commits mailing list
| > | ghc-comm...@haskell.org
| > | http://www.haskell.org/mailman/listinfo/ghc-commits
| >
| >
| >
|
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