From: http://www.haskell.org/haskellwiki/Blow_your_mind#Polynomials
-- splitting in two (alternating)
-- 1234567 - (1357, 246)
-- the lazy match with ~ is necessary for efficiency, especially enabling
processing of infinite lists
foldr (\a ~(x,y) - (a:y,x)) ([],[])
This works but can't
michael rice wrote:
From: http://www.haskell.org/haskellwiki/Blow_your_mind#Polynomials
-- splitting in two (alternating)
-- 1234567 - (1357, 246)
-- the lazy match with ~ is necessary for efficiency, especially enabling
processing of infinite lists
foldr (\a ~(x,y) - (a:y,x))
On Nov 30, 2009, at 12:47 , michael rice wrote:
From: http://www.haskell.org/haskellwiki/Blow_your_mind#Polynomials
-- splitting in two (alternating)
-- 1234567 - (1357, 246)
-- the lazy match with ~ is necessary for efficiency, especially
enabling processing of infinite lists
foldr
So, ALL patterns are strict, unless one precedes them with ~?
Michael
--- On Mon, 11/30/09, Brandon S. Allbery KF8NH allb...@ece.cmu.edu wrote:
From: Brandon S. Allbery KF8NH allb...@ece.cmu.edu
Subject: Re: [Haskell-cafe] Mystery operator?
To: michael rice nowg...@yahoo.com
Cc: Brandon S
On Nov 30, 2009, at 13:26 , michael rice wrote:
So, ALL patterns are strict, unless one precedes them with ~?
case patterns are strict (this includes pattern matching in function
arguments).
let patterns are lazy.
--
brandon s. allbery [solaris,freebsd,perl,pugs,haskell]
Am Montag 30 November 2009 19:26:13 schrieb michael rice:
So, ALL patterns are strict, unless one precedes them with ~?
Or they appear in a let-binding:
Prelude let f xs = let (x:y:zs) = xs in True
Prelude f []
True
Michael
___
Haskell-Cafe
Am Montag 30 November 2009 19:32:01 schrieb Brandon S. Allbery KF8NH:
On Nov 30, 2009, at 13:26 , michael rice wrote:
So, ALL patterns are strict, unless one precedes them with ~?
case patterns are strict (this includes pattern matching in function
arguments).
let patterns are lazy.
And of
that would dictate choosing one
over the other.
Thanks,
Michael
--- On Mon, 11/30/09, Daniel Fischer daniel.is.fisc...@web.de wrote:
From: Daniel Fischer daniel.is.fisc...@web.de
Subject: Re: [Haskell-cafe] Mystery operator?
To: haskell-cafe@haskell.org
Date: Monday, November 30, 2009, 1:35 PM
On Mon, Nov 30, 2009 at 2:01 PM, michael rice nowg...@yahoo.com wrote:
Hi all,
A lot of things posted here I wasn't aware of. My original example involved
~(x,y), so,
returning to that context, how would these two simple cases vary:
add2 :: (Int,Int) - Int
add2 (x,y) = x+y
add2 ::
Consider these two functions:
z = ([], [])
alt1 = foldr f z where
f a (x,y) = (a:y, x)
alt2 = foldr g z where
g a ~(x,y) = (a:y, x)
alt1 (1:2:3:undefined)
= foldr f z (1:2:3:undefined)
= f 1 (foldr f z (2:3:undefined))
-- Now f 1 needs to evaluate its second argument for the pattern
Am Montag 30 November 2009 20:01:04 schrieb michael rice:
Hi all,
A lot of things posted here I wasn't aware of. My original example involved
~(x,y), so, returning to that context, how would these two simple cases
vary:
add2 :: (Int,Int) - Int
add2 (x,y) = x+y
add2 :: (Int,Int) - Int
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