Am 03/25/2015 um 07:00 PM schrieb divyanshu ranjan:

Hi martin,

Check dlist (https://hackage.haskell.org/package/dlist-0.7.1.1).

I cannot see how I can create a dlist via a list comprehension, other than running fromList. But I assume this already has o(n) complexity. It may pay after several appends, though. What I am looking for is, if I have: veryLongList = [x | x <- ...] how can I use list a comprehension and end up with a dlist?

On Wed, Mar 25, 2015 at 11:21 PM, martin mailto:martin.drautzburg@web.de> wrote:

Hello all,

when I write my own recursions, I often end up with something like

a : b : c : (f x)

where f x returns a list. I assume this avoids the costly (++) function, right?

But when I use list comprehensions I always get a complete list and it is costly to append something to it. How can I use the power of list comprehensions, but return an [a]->[a] instead of an [a]?

Is this a good idea at all, or will I pile up thunks?

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