Back-porting pattern synonym type signature syntax for GHC 7.8.4 [Re: ANNOUNCE: GHC 7.8.4 Release Candidate 1]
Simon Peyton Jones
simonpj at microsoft.com
Wed Nov 26 09:49:34 UTC 2014
a) We do not generally make user-visible changes in a patch-level
release, so we would not normally do this in 7.8.2, let alone 7.8.4
b) The 7.8.4 release candidate is out already
c) It would take a little care to back-port the syntax changes to 7.8
without pattern signature (which we definitely don't want). And
there would be a knock on effect in Haddock perhaps?
d) BUT pattern synonyms are a brand new feature in 7.8
and minimising differences between 7.8 and 7.10 would be good.
My instinct is that (a)-(c) overwhelm (d); i.e. let sleeping dogs lie. But what do others think?
| -----Original Message-----
| From: ghc-devs [mailto:ghc-devs-bounces at haskell.org] On Behalf Of Dr.
| ERDI Gergo
| Sent: 26 November 2014 00:59
| To: Austin Seipp
| Cc: ghc-devs at haskell.org
| Subject: Back-porting pattern synonym type signature syntax for GHC
| 7.8.4 [Re: ANNOUNCE: GHC 7.8.4 Release Candidate 1]
| Now that we know what the syntax of pattern synonym type signatures is
| going to be for GHC 7.10, would it make sense / is it not too late to
| backport that same syntax to 7.8.4?
| To recap, 7.8 doesn't support adding type signatures to pattern
| synonyms, but GHCi's ":i" and Haddock both need to produce output
| which has them.
| There's a horrible hacked-together syntax in 7.8 which is very much
| *not* the syntax that will be used in 7.10.
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| `---= gergo at erdi.hu =-------'
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