2 replies to this topic

[abderrahim]

Hi everybody!
i'm a new Haskell guy!! and my question is simple: i don't know why the first definition works as the second doesn't??

delete a (x:xs) = if (x==a) then (delete a xs) else (x: (delete a xs))

delete a [] = []

delete a r   

                 |r==[] = []

		 |otherwise = if (a==(head r)) then (delete a (tail r)) else ((head a) :(delete a (tail r)))

[Sysop_fb]

((head a) :(delete a (tail r)))

Look carefully at how you're treating a in (head a) and what haskell is inferring the type of a to be based on how you've used it thus far.

[abderrahim]

aaaaa, thank you, it should be (tail r) not (tail a),
Thank you!