lazy Printing question

[David Roundy]

On Mon, Jul 21, 2003 at 05:41:32PM +0530, AJ wrote:
> Hi everyone,

Hi!

> I have written the following program to find "magic numbers"
> i.e. integers 'n' such that both (n+1) and (n/2+1) are perfect squares.
> 
> Import IO
> 
> main :: IO ()
> main =
> 	do
> 	print (filter magicP sqs)

> Now my question is - How do I reproduce such "lazy printing" behaviour in
> GHC?

My guess would be to try running 

main = putStr $ unlines $ map show $ filter magicP sqs

It may be that print is doing something like checking the length of the
list which would of course not allow for lazy printing.
-- 
David Roundy
http://www.abridgegame.org