[wyager]

Huh? No, anyone who writes it in Haskell would not use those lambda abstractions. You would just use "filter isValid (map Person names)".

[Scriptor]

I'm assuming Person is a record constructor, is isValid here a field in that record or another function?

[prodigal_erik]

Haskell doesn't distinguish the two. If you define Person with named fields including isValid, you automatically get a function named isValid that returns that field, or you can write your own isValid function that examines the whole Person.