Bryan O'Sullivan
Pete Kazmier wrote:
I understand the intent of this code, but I am having a hard time understanding the implementation, specifically the combination of 'fix', 'flip', and 'interate'. I looked up 'fix' and I'm unsure how one can call 'flip' on a function that takes one argument.
As to why it's okay to call "flip" on "fix" at all, look at the types involved.
fix :: (a -> a) -> a flip :: (a -> b -> c) -> b -> a -> c
By substitution:
flip fix :: a -> ((a -> b) -> a -> b) -> b
Sadly, I'm still confused. I understand how 'flip' works in the case where its argument is a function that takes two arguments. I've started to use this in my own code lately. But my brain refuses to understand how 'flip' is applied to 'fix', a function that takes one argument only, which happens to be a function itself. What is 'flip' flipping when the function passed to it only takes one argument? Thanks, Pete