On Fri, Aug 23, 2013 at 10:12:27AM +0200, Erik Hesselink wrote:
> Note that the 'normal' hoogle indexes all (?) of hackage. But by
> default it only searches the haskell platform. You can add a package
> with '+' to search in that package. E.g. "PublicKey +crypto-api".
If the idea behind this, th
Hi Tom,
> See [1] for an explanation of free monads in general. For IO in particular,
> define a functor
>
> data IOF a = GetChar (Char -> a) | PutChar Char a | ...
>
> with constructors for all elementary IO operations.
But how should this work if the user adds an IO operation, e.g by wr
Hi John,
> Alan - I do NOT want to generate Haskell code. I want only to generate AST
> and compile it.
> The question about generating the code was only to have a "debugging tool"
> - to see if the generated AST is good - I wanted to generate the Haskell
> code only to check if its correct, but
Hi Adrian,
> What's an exception? I thought Haskell used Maybe.
Haskell also has exceptions:
dan@machine ~> ghci
Prelude> head []
*** Exception: Prelude.head: empty list
I also consider them as quite problematic, especially if they're used in
libraries, but sometimes we're all a bit lazy and
Hi Mateusz,
> I don't think my post was out of order at all and I don't understand
> why it sparked such an... energetic response - that wasn't my intent
> at all.
A friendly response might contain the things you told John, but it could
also be a bit more empathic, otherwise its easy to perceive
Hi Nathan,
> DataAlt c | Right tag <- genDataConTag c -> return $ Cond tag
Are you sure, that genDataConTag always returns a 'Right'?
If it returns a 'Left', than the pattern won't match.
Greetings,
Daniel
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Hi Jan,
On Tue, Apr 09, 2013 at 01:32:33PM +0200, Jan Stolarek wrote:
> Thanks for pointing me to earlier discussions on this subject - they are
> enlightening :) One
> particular argument "against" seems to be very convincing to me:
>
> "From a language design point of view, it should be note
Hi Roman,
> In fact, lots of Haskell newcomers are surprised that
>
> f 10 = 42
>
> is not the same as
>
> n = 10
> f n = 42
Well, yes, at the beginning I've been also surprised about this.
But allowing this seems to be even more error prone, because now you
could "bind" function argum
Hi Roman,
> One issue with it in Haskell is that it'd lead to inconsistent
> semantics:
>
> myEq x x = True
>
> is not the same as
>
> myEq x y =
> case y of
> x -> True
I don't think that it's inconsistent, because the 'case' defines a new name
scope, like the function does for
Hi Steffen,
most of the time I'm just using these cpp macros:
#define __POS__(__FILE__ ++ ":" ++ show __LINE__)
#define ERROR error $ __POS__ ++ " -> " ++
Instead of writing 'error "blub"' you would write 'ERROR "blub"'
and additionally get the file name and the line.
There's a brac
Hi Corentin,
On Wed, Mar 27, 2013 at 09:13:41PM +0100, Corentin Dupont wrote:
> I have a function that looks like this:
> call :: SomeFunction -> String -> SomeState
>
> The string is actually the representation of the function passed in
> parameter. It is stored in the state for documentation.
Hi Michael,
On Sun, Mar 24, 2013 at 05:13:35PM -0500, Michael Better wrote:
> Isn't this similar to the problem Cloud Haskell had to solve to send code
> to another process to run?
As much as I know, the sendable code of 'Cloud Haskell' is limited, you
can't just send any kind of function.
http
Hi Corentin,
> I have a DSL like this:
> data Exp where
> OnEvent :: EventName -> (Int -> Exp) -> Exp
> (...)
>
> The "OnEvent" element carries a function (the handler to be called when the
> event happens), and that makes my DSL non showable/serializable.
> How could I fix that? This i
Hi Peter,
> -- smart constructor with serialNumber
> date serialNumber
> | serialNumber > 0 = Date serialNumber
> | otherwise = error ("invalid serialNumber " ++ show serialNumber)
Instead of raising an error it's more secure to return a Maybe value.
date :: Int -> Maybe Date
Hi Michael,
On Mon, Feb 25, 2013 at 02:41:19PM +0200, Michael Snoyman wrote:
> At that point, we've now made two changes to REWRITE rules:
>
> 1. They can takes a new ALWAYS parameters.
> 2. There's a new, special identifier currentLocation available.
>
> What would be the advantage is of that
On Tue, Feb 19, 2013 at 02:15:33PM +0100, Vo Minh Thu wrote:
> Screenshots obviously ;)
Hurray!
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Hi Henk-Jan,
> It seems to me that there is something missing from this e-mail.
What are you missing?
Greetings,
Daniel
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Hi all,
also if there's not that much to see and only a few minutes of gameplay,
but after spending quite a few hours writing it, getting a feeling for
Haskell and it's usage, perhaps it's in some way useful for someone,
even if just for a few minutes of distraction.
https://github.com/dan-t/lay
Hi Alex,
On Fri, Jan 18, 2013 at 08:26:10PM +0100, Alexander Bernauer wrote:
> I thought it would make sense to use these names for ease of
> reference. Given this, would you still prefer them being grouped in
> separate modules?
Yes, I still think that having separate modules can be beneficial,
Hi Alexander,
On Thu, Jan 17, 2013 at 10:17:33PM +0100, Alexander Bernauer wrote:
> I am happy to announce the second release of hgdbmi, a Haskell
> implementation of the GDB Machine Interface.
Nice project! :)
> PS: This is my first serious Haskell package. If you see something
> that you cons
Hi Christopher,
On Fri, Dec 21, 2012 at 04:36:04AM -0900, Christopher Howard wrote:
> Using a simple type I gave earlier from my monadic type question...
>
> code:
>
> data Socket3 a b c = Socket3 a b c
> deriving (Show)
>
>
> Is it possible somehow to layer on record syntax
On Thu, Dec 13, 2012 at 08:40:09PM +0200, Michael Snoyman wrote:
> If you have a commercial use for cpphs, and feel the terms of the (L)GPL
> are too onerous, you have the option of distributing unmodified binaries
> (only, not sources) under the terms of a different licence (see
> LICENCE-commerc
Greetings,
Daniel
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Hi Joachim,
On Sun, Nov 11, 2012 at 02:10:34PM +0100, Joachim Breitner wrote:
> dear package authors. If you define a useful class, please think twice
> before you do not export the methods, otherwise something like this will
> happen:
I like the way 'Common Lisp' deals with this issue. Exported
Hi all,
I'm currently struggling in the search for a nice abstraction for the
input handling of a game (it's a simple platformer with rectangular platforms).
One good example is the level editor of the game. When pressing the left
mouse button the creation of a new platform is started. As long a
Hi Jon
On Wed, Oct 24, 2012 at 11:08:29AM +0100, Jon Fairbairn wrote:
> for each field, which is tedious (and O(n)). Obviously Templates
> would help, but is there an alternative I’ve missed?
perhaps something like:
data Type = Ta | Tb | Tc ...
data E= Ea A | Eb B | Ec C | ...
type D=
On Thu, Aug 16, 2012 at 11:33:17PM -0400, wren ng thornton wrote:
> However, there are certainly cases where we have hard upper
> bounds[1][2][3], and ignoring those is not fine. Circumventing hard
> upper bounds should require altering the .cabal file, given as
> getting things to compile will re
On Wed, Aug 15, 2012 at 03:54:04PM -0700, Michael Sloan wrote:
> Upper bounds are a bit of a catch-22 when it comes to library authors evolving
> their APIs:
>
> 1) If library clients aren't encouraged to specify which version of the
>exported API they target, then changing APIs can lead to o
Hi Oleg,
On Sat, Aug 11, 2012 at 08:14:47AM -, o...@okmij.org wrote:
> I'd like to point out that the only operation we can do on the first
> argument of MkFoo is to show to it. This is all we can ever do:
> we have no idea of its type but we know we can show it and get a
> String. Why not to
Hi Joey,
On Tue, Aug 07, 2012 at 02:13:09PM -0400, Joey Adams wrote:
> Are you looking for existential quantification [1]?
>
> data SomeFoo = forall a. Foo a => a
>
> [1]:
> http://www.haskell.org/ghc/docs/latest/html/users_guide/data-type-extensions.html#existential-quantification
Thank
Hi all,
it should be possible a call a function on all elements of the data
structure, to add and remove elements.
What I currently have:
the type class:
class Foo a where
hasId :: a -> Int -> Maybe a
a few instances:
data A = A deriving Show
instance Foo A where
hasId a 1 = Just a
Hi Ivan,
thanks, but l have been able to build it by myself.
I just want to get the package updated and if the maintainer can't be
reached, than ask for maintainership.
Greetings,
Daniel
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Hi,
Marko Lauronens email address from the package is invalid, so I'm trying
to reach him this way.
pngload doesn't compile with ghc >= 7.2 because of it's dependency to base and
haskell98.
Greetings,
Daniel
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