Rejecting due to reasons pointed out below.

They are the arguments of the function, like in any other program (python def f(xs):). But sometimes it is possible to not write them, like here, if we can write the code in pure terms of functions combinations. It's hard to explain clearly (and I'm far from being comfortable in Haskell) but try to practice on easy katas and look at others solutions, try to reuse them... With Haskell installed on your computer you can run a very handy interpreter that allows to do tiny tests easily.

can someone explain this. Very new to haskell.
I am wondering why "xs" or any form of agruement is being used before the equal sign?

so cool!

Really cool approach. It's these kinds of code that made me learn haskell at first. Doing simple things the simple way

No, siempre hay una forma mas redusida jajaj

A couple more edge cases to test: 0 octets (starts with "0", but valid), plus signs in numbers (parseable Int, but invalid).
It would be nice to make it compatible with GHC 8 too.

Yeah! I was wondering if this could be done without having to destructure the pair... learning so much from everyone here :)

so Good!!!!!