[Haskell-cafe] a minor bug (memory leak) in ListLike package

[Ivan Lazar Miljenovic]

On 24 August 2011 11:10, bob zhang <bobzhang1988 at gmail.com> wrote:
> Hi, John, there is a space leak problem in ListLike typeclass,
> in the method genericLength
> calclen !accum cl =
> calclen accum cl =

I _think_ this may cause problems with some data types (e.g.
http://hackage.haskell.org/packages/archive/numbers/2009.8.9/doc/html/Data-Number-Natural.html
) that require the extra laziness (that is, you can do things like ` 3
< genericLength [1..] ' and have it return True).

> --- thank you for your nice library
> btw, is there any way to derive ListLike interface automatically?
> for such type :
> newtype List a = List {[a]}

GeneralizedNewtypeDeriving can do that.

-- 
Ivan Lazar Miljenovic
Ivan.Miljenovic at gmail.com
IvanMiljenovic.wordpress.com