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 for
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
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 the
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 discover
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 the result, at
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 more
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!
It should work fine, you'll need
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
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
computer,
like any other
* 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
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,
Bulat
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
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 ?
it is
...@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 any plans to incorporate some
|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 =
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 existential
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.
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 being
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 using undefined,
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
On Sat, Apr 18, 2009 at 9:03 AM, a...@cs.uu.nl 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
On 18 Apr 2009, at 22:44, Antoine Latter wrote:
On Sat, Apr 18, 2009 at 9:03 AM, a...@cs.uu.nl wrote:
Utrecht Haskell Compiler -- first release, version 1.0.0
The UHC team is happy to announce the first public
On Sat, Apr 18, 2009 at 4:38 PM, Thomas Davie tom.da...@gmail.com 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
On 19 Apr 2009, at 00:31, Antoine Latter wrote:
On Sat, Apr 18, 2009 at 4:38 PM, Thomas Davie tom.da...@gmail.com
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,
I've learnt (the hard way) not to trust user installs at all.
On Sun, Apr 19, 2009 at 12:41 AM, Thomas Davie tom.da...@gmail.com wrote:
On 19 Apr 2009, at 00:31, Antoine Latter wrote:
On Sat, Apr 18, 2009 at 4:38 PM, Thomas Davie tom.da...@gmail.com wrote:
This looks like the same error I
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