Thanks guys for the clarification, this blowed my mind a bit :P
As far as I understood, is that my initial thought about Sum and Product
was wrong; in fact, they don't even participate to the party!
This is confirmed by the Oleg's paradox about (-).
What really happens is that Endo (which I guess
Hi Cafe,
I was playing with the classic example of a Foldable structure: Trees.
So the code you can find both on Haskell Wiki and LYAH is the following:
data Tree a = Empty | Node (Tree a) a (Tree a) deriving (Show, Eq)
instance Foldable Tree where
foldMap f Empty = mempty
foldMap f
Le 23 oct. 2012 09:54, Alfredo Di Napoli alfredo.dinap...@gmail.com a
écrit :
What this code does is straighforward. I was struck from the following
sentences in LYAH:
Notice that we didn't have to provide the function that takes a value
and returns a monoid value.
We receive that function as
-- Forwarded message --
From: Alfredo Di Napoli alfredo.dinap...@gmail.com
Date: 23 October 2012 10:35
Subject: Re: [Haskell-cafe] A clarification about what happens under the
hood with foldMap
To: Chaddaï Fouché chaddai.fou...@gmail.com
I'm sure I'm missing a point, but the
I was playing with the classic example of a Foldable structure: Trees.
So the code you can find both on Haskell Wiki and LYAH is the following:
data Tree a = Empty | Node (Tree a) a (Tree a) deriving (Show, Eq)
instance Foldable Tree where
foldMap f Empty = mempty
foldMap f (Node
On Tue, Oct 23, 2012 at 10:36 AM, Alfredo Di Napoli
alfredo.dinap...@gmail.com wrote:
I'm sure I'm missing a point, but the minimum definition for a Foldable
instance is given in terms of foldMap, so I get the cake for free, foldr
included, right?
In the example I have defined my treeSum as:
Thanks guys,
I'll work my way through Oleg's paradox as well as what you just said
Chaddai.
I'm very busy right now, but I'll probably come back to you tomorrow
morning, when I'll have an hour to think freely :)
Cheers,
A.
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Haskell-Cafe mailing list
From: Alfredo Di Napoli alfredo.dinap...@gmail.com
Subject: [Haskell-cafe] A clarification about what happens under the
hoodwith foldMap
I'm sure I'm missing a point, but the minimum definition for a Foldable
instance is given in terms of foldMap, so I get the cake for free,
