import Control.Applicative
data Pair a = a :*: a
instance Functor Pair where
f `fmap` (x :*: y) = f x :*: f y
instance Applicative Pair where
(f :*: g) * (x :*: y) = f x :*: f y
The last f needs to be a g.
pure x = x :*: x
pointfree :: (a - b - c) - Pair a -
And then to
down = mconcat [downPar, downNew, downTrans]
Which is pretty cute considering that the original formulation is equivalent
to and a tiny tweak away from
down p = mconcat [downPar p, downNew p, downTrans p]
Hooray for Monoid!
- Conal
On Mon, Feb 9, 2009 at 6:31 AM, Wouter
On Thu, Feb 12, 2009 at 6:46 PM, Kim-Ee Yeoh a.biurvo...@asuhan.com wrote:
On the same note, does anyone have ideas for the following snippet? Tried the
pointfree package but the output was useless.
pointwise op (x0,y0) (x1,y1) = (x0 `op` x1, y0 `op` y1)
$ pointfree '(\op (a, b) (c, d) - (a
On Mon, 9 Feb 2009, Edsko de Vries wrote:
Hi,
Is there a nice way to write
down :: Focus - [Focus]
down p = concat [downPar p, downNew p, downTrans p]
down = concat . sequence [downPar, downNew, downTrans]
given the Reader like Monad instance of ((-) a).
On the same note, does anyone have ideas for the following snippet? Tried the
pointfree package but the output was useless.
pointwise op (x0,y0) (x1,y1) = (x0 `op` x1, y0 `op` y1)
Edsko de Vries wrote:
Perfect! Beautiful. I was hoping there'd be a simple solution like that.
Thanks!
Hi,
Is there a nice way to write
down :: Focus - [Focus]
down p = concat [downPar p, downNew p, downTrans p]
in point-free style? (In doesn't make much difference what these
functions do; if it helps, their types are downPar, downNew,
downTrans :: Focus - [Focus]).
Ideally, I would like
On Mon, 9 Feb 2009 14:18:18 +
Edsko de Vries devri...@cs.tcd.ie wrote:
Hi,
Is there a nice way to write
down :: Focus - [Focus]
down p = concat [downPar p, downNew p, downTrans p]
in point-free style?
I think this should work:
down = concat . swing map [downPar, downNew,
snip
How about using Data.Monoid:
down = downPar `mappend` downNew `mappend` downTrans
Wouter
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Rewriting it to:
concatMap ($ p)[downPar , downNew , downTrans ]
gives:
($ p) = [downPar, downNew, downTrans]
didn't check though!
=@@i
Edsko de Vries schreef:
Hi,
Is there a nice way to write
down :: Focus - [Focus]
down p = concat [downPar p, downNew p, downTrans p]
in point-free
Perfect! Beautiful. I was hoping there'd be a simple solution like that.
Thanks!
On 9 Feb 2009, at 14:31, Wouter Swierstra wrote:
snip
How about using Data.Monoid:
down = downPar `mappend` downNew `mappend` downTrans
Wouter
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