I don't really see how recursing into some other inits function would help. The same laziness requirement should hold everywhere: take (n+1) $ inits ([1 .. n] ++ undefined) = inits [1 .. n] Maybe I don't understand what you mean properly. On Sat, Jul 19, 2014 at 4:29 AM, Henning Thielemann < schlepptop@henning-thielemann.de> wrote:
Am 19.07.2014 10:25, schrieb David Feuer:
I'm not sure about the theory of it, but if I load the module in GHCi
and run head $ last $ initsR [0..100000::Int] I get a response *immediately*. If I run head $ last $ initsDL [0..100000::Int] I wrote this email while waiting for that to complete, and gave up on it. There may be an asymptotic performance bug here.
Sorry, I got the implementation of initsDL wrong (recursed into the wrong inits-function).