I went back and tried to convert the YAHT example to Monad, importing Monad,
commenting out all but the data descriptions and the searchAll function, and
finally replacing success, failure, augment, and combine in the searchAll
function with return, fail, =, and mplus.
*Main let g = Graph
Am Montag 01 Juni 2009 19:02:36 schrieb michael rice:
All good so far, but then tried to convert Failable from Computation to
Monad
instance Monad Failable where
return = Success
fail = Fail
= (Success x) f = f x
= (Fail s) _ = Fail s
mplus (Fail _) y = y
mplus
Got it.
Thanks!
Michael
--- On Mon, 6/1/09, Daniel Fischer daniel.is.fisc...@web.de wrote:
From: Daniel Fischer daniel.is.fisc...@web.de
Subject: Re: [Haskell-cafe] Missing a Deriving?
To: haskell-cafe@haskell.org
Date: Monday, June 1, 2009, 1:51 PM
Am Montag 01 Juni 2009 19:02:36 schrieb
Still stumped. Maybe and [] are in the same MonadPlus monad, but how do I make
monad Failable understand mplus?
I'm now getting this error upon loading:
Prelude :l graph5
[1 of 1] Compiling Main ( graph5.hs, interpreted )
graph5.hs:36:4: `mplus' is not a (visible) method of class
mplus is a method of class MonadPlus, so you need to write it in a
separate instance from the one for Monad, e.g.
instance MonadPlus Failable where
mplus = ...
-Ross
On Jun 1, 2009, at 9:28 PM, michael rice wrote:
Still stumped. Maybe and [] are in the same MonadPlus monad, but how
do
/1/09, Ross Mellgren rmm-hask...@z.odi.ac wrote:
From: Ross Mellgren rmm-hask...@z.odi.ac
Subject: Re: [Haskell-cafe] Missing a Deriving?
To: michael rice nowg...@yahoo.com
Cc: haskell-cafe Cafe haskell-cafe@haskell.org
Date: Monday, June 1, 2009, 9:33 PM
mplus is a method of class MonadPlus, so
it mplus)?
Michael
--- On Mon, 6/1/09, Ross Mellgren rmm-hask...@z.odi.ac wrote:
From: Ross Mellgren rmm-hask...@z.odi.ac
Subject: Re: [Haskell-cafe] Missing a Deriving?
To: michael rice nowg...@yahoo.com
Cc: haskell-cafe Cafe haskell-cafe@haskell.org
Date: Monday, June 1, 2009, 9:33 PM
mplus
searchAll g 3 1 :: Maybe [Int]
Nothing
*Main searchAll g 1 3 :: [[Int]]
[[1,2,3],[1,4,3]]
*Main searchAll g 3 1 :: [[Int]]
[]
*Main
--- On Mon, 6/1/09, Ross Mellgren rmm-hask...@z.odi.ac wrote:
From: Ross Mellgren rmm-hask...@z.odi.ac
Subject: Re: [Haskell-cafe] Missing a Deriving?
To: michael
1 :: [[Int]]
[]
*Main
--- On Mon, 6/1/09, Ross Mellgren rmm-hask...@z.odi.ac wrote:
From: Ross Mellgren rmm-hask...@z.odi.ac
Subject: Re: [Haskell-cafe] Missing a Deriving?
To: michael rice nowg...@yahoo.com
Cc: haskell-cafe Cafe haskell-cafe@haskell.org
Date: Monday, June 1, 2009, 9:43
It's trying to 'Show' the 'c [Int]' type, but doesn't know which 'c'
to use; so it's trying to find a generic instance, which doesn't
exist. You can't fix this with 'deriving' or anything like this;
instead, provide the type annotation like this:
*Main searchAll g 1 3 :: Maybe [Int]
On 31
michael rice nowg...@yahoo.com writes:
The following code is from Section 8.4.2, pgs. 111-112 (PDF paging) of YAHT.
It compiles fine, but upon trying it I get the following error message.
It seems to be trying to 'Show' the Computation class but I'm not sure where
to put the 'Deriving'.
My
there are five
possibilities.
MIchael
--- On Sat, 5/30/09, Miguel Mitrofanov miguelim...@yandex.ru wrote:
From: Miguel Mitrofanov miguelim...@yandex.ru
Subject: Re: [Haskell-cafe] Missing a Deriving?
To: michael rice nowg...@yahoo.com
Cc: haskell-cafe@haskell.org
Date: Saturday, May 30, 2009, 5:36 PM
On Sat, May 30, 2009 at 9:00 PM, michael rice nowg...@yahoo.com wrote:
That works. but it gives just a single solution [1,2,3] when there are
supposed to be two [[1,2,3],[1,4,3]]. Of course the code in YAHT may be in
error.
Works for me.
*Main searchAll g 1 3 :: [[Int]]
[[1,2,3],[1,4,3]]
On Sat, May 30, 2009 at 6:33 PM, David Menendez d...@zednenem.com wrote:
*Main :t searchAll
searchAll :: (Computation c) = Graph t t1 - Int - Int - c [Int]
The way searchAll is written, the choice of which functions to use
depends on the type variable c. That's determined by the calling
Menendez d...@zednenem.com
Subject: Re: [Haskell-cafe] Missing a Deriving?
To: michael rice nowg...@yahoo.com
Cc: Miguel Mitrofanov miguelim...@yandex.ru, haskell-cafe@haskell.org
Date: Saturday, May 30, 2009, 9:33 PM
On Sat, May 30, 2009 at 9:00 PM, michael rice nowg...@yahoo.com wrote
Belay that last question. I just realized that its the const function being
used rather than a constant declaration in const Nothing and const [].
MIchael
--- On Sat, 5/30/09, David Menendez d...@zednenem.com wrote:
From: David Menendez d...@zednenem.com
Subject: Re: [Haskell-cafe] Missing
Hi Ryan,
Is there something missing or mislabeled in your post, because I don't see any
definition of toDynamic.
Michael
--- On Sun, 5/31/09, Ryan Ingram ryani.s...@gmail.com wrote:
From: Ryan Ingram ryani.s...@gmail.com
Subject: Re: [Haskell-cafe] Missing a Deriving?
To: David Menendez d
, because I don't see
any definition of toDynamic.
Michael
--- On Sun, 5/31/09, Ryan Ingram ryani.s...@gmail.com wrote:
From: Ryan Ingram ryani.s...@gmail.com
Subject: Re: [Haskell-cafe] Missing a Deriving?
To: David Menendez d...@zednenem.com
Cc: michael rice nowg...@yahoo.com, haskell
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