[Haskell-cafe] Combine list of sorted lists
dmhouse at gmail.com
Fri Dec 29 14:47:05 EST 2006
Sorry to Neil for multiple copies.
On 29/12/06, Neil Mitchell <ndmitchell at gmail.com> wrote:
> > I am not sure how to express f1 with map? how do I say
> > (lambda (ls)
> > (map (lambda (x) (list x))
> > ls))
> > in Haskell? map () ?
> map (:), : takes a single element and puts it into a list. Some
> people refer to this as "box"
You can pretty much directly translate your Lisp:
\ls -> map (\x -> [x]) ls
Which eta-reduces to:
map (\x -> [x])
Now the inner lambda can be written as:
\x -> x : 
That's a section on the ':' operator. So the whole thing becomes:
Hope that helps.
-David House, dmhouse at gmail.com
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