Re: [Haskell-cafe] A probably-stupid question about a Prelude implementation.

Neil Mitchell wrote:

Hi Michael,

You're wrong :)

...

foldr (||) False (repeat True)

Gives:

...

True

Remember that in Haskell everything is lazy, which means that the || short-circuits as soon as it can.

Thanks

Neil

Specifically it is graph reduced like this: or [F,T,F,F...] foldr (||) F [F,T,F,F...] F || foldr (||) F [T,F,F...] foldr (||) F [T,F,F...] T || foldr (||) F [F,F...] T The last line is because (T || _ = T) and lazyness