Subject: Re: filter funcation usage

> 
> Hi!
> Could you give me a example of FILTER function, I type predule source but I
> don't know how to describe p in FILTER p (x:xs).
> Thanks.
> 

See the text book!

filter even [1,2,3,4,5,6]  => [2,4,6]

I.e. filter takes a predicate (a function from
some type a to Bool, a->Bool), and a list
of elements of type a as argument, and returns
those elements from the list that satisfy
the predicate.

even returns True for 2, 4, & 6, and hence,
filter even [1,2,3,4,5,6]  returns those
elements in a list.

/CC