deprecating

[Simon Peyton-Jones]

| I thought the point of these extension flags was to be cross-compiler?
| So it seems a bit odd to make a change for the benefit of one compiler.
| 
| Here's my interpretation: Rank2Types is not a synonym for RankNTypes.
| It's a specific requirement the source file has. When GHC comes to
| compile it, it can satisfy that requirement by switching on its
| RankNTypes. Another compiler might support Rank2Types but not
| RankNTypes, and it would also be able to compile the file.

The trouble is that it's painful to check that a program uses rank-2 *only*, which is what you might naively think of the flag.  So rather than fiddle about with distinctions that no one really cares about, the idea is to abolish the distinction.

But if the will of the masses is to silently and forever make Rank2Types=RankNtypes (documented of course), that's ok with me.  It just seems odd.  I thought that's what deprecation was *for*.  

Simon
| 
| -- Ashley
| 
| On 19/10/12 09:53, Simon Peyton-Jones wrote:
| > See my response on
| > http://hackage.haskell.org/trac/ghc/ticket/6032#comment:6
| > Not sure what the best path is here
| >
| > S
| >
| > | -----Original Message-----
| > | From: Johan Tibell [mailto:johan.tibell at gmail.com]
| > | Sent: 19 October 2012 17:39
| > | To: Simon Peyton-Jones
| > | Cc: Don Stewart; Duncan Coutts; Roman Leshchinskiy;
| > | ashley at semantic.org; cabal-devel at haskell.org; Ben Lippmeier; Manuel
| > | M T Chakravarty; cvs-ghc at haskell.org
| > | Subject: Re: deprecating
| > |
| > | Hi Simon,
| > |
| > | On Fri, Oct 19, 2012 at 4:49 AM, Simon Peyton-Jones
| > | <simonpj at microsoft.com> wrote:
| > | > As discussed in Trac #6032 I am deprecating
| > | >
| > | >           Rank2Types
| > | >
| > | >           PolymorphicComponents
| > | >
| > | > in favour of the single flag
| > | >
| > | >           RankNTypes
| > |
| > | I'm fine with making the changes to cabal, but before I do, I want
| > | to make sure that we really want to do this. I did a quick
| > | investigation of how many modules need to be updated on Hackage.
| It's about 775.
| > | That will require quite a lot of work by quite a lot of people.
| > | Could we instead have Rank2Types be an alias for RankNTypes?
| > |
| > | Cheers,
| > | Johan
| >
| >
|