> data EShow = forall a. Show a => EShow a
>
> data E t = forall a. E (a->t) a
>
> smallPrint_ t = concatMap (\f-> f t) [show . foo, show . bar, show . baz]
Yeah, I am aware of these solutions, but like Dan says:
> but first-class existentials are still desirable because introducing a new
> type
On Sunday 19 April 2009 9:31:27 pm Derek Elkins wrote:
> > simply because this is essentially a function with type
> >
> > (forall a. F a) -> (exists a. F a)
> >
> > and you can do that by instantiating the argument to any type, and then
> > hiding it in an existential),
>
> You can do this by us
On Sun, 2009-04-19 at 20:46 -0400, Dan Doel wrote:
> On Sunday 19 April 2009 7:11:51 pm wren ng thornton wrote:
> > Yes, however, because consumers (e.g. @f@) demand that their arguments
> > remain polymorphic, anything which reduces the polymorphism of @a@ in
> > @x@ will make it ineligible for be
On Sunday 19 April 2009 7:11:51 pm wren ng thornton wrote:
> Yes, however, because consumers (e.g. @f@) demand that their arguments
> remain polymorphic, anything which reduces the polymorphism of @a@ in
> @x@ will make it ineligible for being passed to consumers. Maybe not
> precise, but it works.
Dan Doel wrote:
On Sunday 19 April 2009 4:56:29 pm wren ng thornton wrote:
> Bulat Ziganshin wrote:
> > Hello R.A.,
> >
> > Sunday, April 19, 2009, 11:46:53 PM, you wrote:
> > > Does anybody know if there are any plans to incorporate some of
> > > these extensions into GHC - specifically the exis
|data Test = Test { foo :: Int, bar :: Char, baz :: Bool }
|smallPrint t = concatMap (\f -> show $ f t) [foo, bar, baz]
|In this code the list [foo, bar, baz] should have the type [exists a. Show a =>
Test -> a].
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE ExistentialQuantification #-}
data EShow
nshin [bulat.zigans...@gmail.com]
Sent: 19 April 2009 22:07
To: Niemeijer, R.A.
Cc: haskell-cafe@haskell.org
Subject: Re[2]: [Haskell-cafe] ANNOUNCE: Utrecht Haskell Compiler (UHC) --
first release
Hello R.A.,
Sunday, April 19, 2009, 11:46:53 PM, you wrote:
> Does anybody know if there are an
On Sunday 19 April 2009 4:56:29 pm wren ng thornton wrote:
> Bulat Ziganshin wrote:
> > Hello R.A.,
> >
> > Sunday, April 19, 2009, 11:46:53 PM, you wrote:
> >> Does anybody know if there are any plans to incorporate some of
> >> these extensions into GHC - specifically the existential typing ?
> >
Bulat Ziganshin wrote:
Hello R.A.,
Sunday, April 19, 2009, 11:46:53 PM, you wrote:
Does anybody know if there are any plans to incorporate some of
these extensions into GHC - specifically the existential typing ?
it is already here, but you should use "forall" keyword instead odf
"exists"
Hello R.A.,
Sunday, April 19, 2009, 11:46:53 PM, you wrote:
> Does anybody know if there are any plans to incorporate some of
> these extensions into GHC - specifically the existential typing ?
it is already here, but you should use "forall" keyword instead odf
"exists"
--
Best regards,
Bula
> * Experimental language extensions, some of which have not been
>implemented before.
Does anybody know if there are any plans to incorporate some of these
extensions into GHC - specifically the existential typing ?
I would love to be able to use existential typing without having to give up
Am Sonntag 19 April 2009 13:09:17 schrieb Thomas Davie:
> >> I don't understand what makes user installs more convenient.
> >> Certainly,
> >> my preference would be for global all the time I expect something
> >> that
> >> says it's going to "install" something to install it onto my
> >> compute
I don't understand what makes user installs more convenient.
Certainly,
my preference would be for global all the time – I expect something
that
says it's going to "install" something to install it onto my
computer,
like any other installation program does. What is it that makes user
ins
tom.davie:
>
> On 19 Apr 2009, at 11:10, Duncan Coutts wrote:
>
>> On Sun, 2009-04-19 at 10:02 +0200, Thomas Davie wrote:
>>
> It really rather makes "cabal install" rather odd – because it
> doesn't actually install anything you can use without providing
> extra
> options!
>
On 19 Apr 2009, at 11:10, Duncan Coutts wrote:
On Sun, 2009-04-19 at 10:02 +0200, Thomas Davie wrote:
It really rather makes "cabal install" rather odd – because it
doesn't actually install anything you can use without providing
extra
options!
It should work fine, you'll need to give mor
On Sun, 2009-04-19 at 10:02 +0200, Thomas Davie wrote:
> >> It really rather makes "cabal install" rather odd – because it
> >> doesn't actually install anything you can use without providing extra
> >> options!
> >
> > It should work fine, you'll need to give more details.
>
> This has been
On 19 Apr 2009, at 09:52, Duncan Coutts wrote:
On Sun, 2009-04-19 at 00:41 +0200, Thomas Davie wrote:
Apparently a "user" install of uuagc and fgl isn't good enough. Fun
to know.
I've found user installs don't work at all on OS X, various people in
#haskell were rather surprised to discove
On Sun, 2009-04-19 at 00:41 +0200, Thomas Davie wrote:
> > Apparently a "user" install of uuagc and fgl isn't good enough. Fun
> > to know.
>
> I've found user installs don't work at all on OS X, various people in
> #haskell were rather surprised to discover this, so apparently it's
> not
Thomas Davie wrote:
I've found user installs don't work at all on OS X, various people in
#haskell were rather surprised to discover this, so apparently it's not
the default behavior on other platforms.
It really rather makes "cabal install" rather odd – because it doesn't
actually install an
I've learnt (the hard way) not to trust user installs at all.
On Sun, Apr 19, 2009 at 12:41 AM, Thomas Davie wrote:
>
> On 19 Apr 2009, at 00:31, Antoine Latter wrote:
>
>> On Sat, Apr 18, 2009 at 4:38 PM, Thomas Davie wrote:
>>>
>>> This looks like the same error I got – see bug report 1 in the
On 19 Apr 2009, at 00:31, Antoine Latter wrote:
On Sat, Apr 18, 2009 at 4:38 PM, Thomas Davie
wrote:
This looks like the same error I got – see bug report 1 in the bug
database
– the configure script reports that you have uuagc even if you
don't – cabal
install it, reconfigure, and you
On Sat, Apr 18, 2009 at 4:38 PM, Thomas Davie wrote:
>
> This looks like the same error I got – see bug report 1 in the bug database
> – the configure script reports that you have uuagc even if you don't – cabal
> install it, reconfigure, and you should be on your way.
>
> Second thing to watch fo
On 18 Apr 2009, at 22:44, Antoine Latter wrote:
On Sat, Apr 18, 2009 at 9:03 AM, wrote:
Utrecht Haskell Compiler -- first release, version 1.0.0
The UHC team is happy to announce the first public release of the
On Sat, Apr 18, 2009 at 9:03 AM, wrote:
> Utrecht Haskell Compiler -- first release, version 1.0.0
>
>
>
> The UHC team is happy to announce the first public release of the
> Utrecht Haskell Compiler (UHC). UHC support
Utrecht Haskell Compiler -- first release, version 1.0.0
The UHC team is happy to announce the first public release of the
Utrecht Haskell Compiler (UHC). UHC supports almost all Haskell98
features plus many experime
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