w.r.t. x::xs vs. head::tail One of the nice conceptual things about pattern matching is the pattern on the left hand side describes which bits of the structure

w.r.t. x::xs vs. head::tail One of the nice conceptual things about pattern matching is the pattern on the left hand side describes which bits of the structure you're interested in, while the stuff on the right hand side describes how to manipulate that data. When you're looking at the rhs it shouldn't care about where data came from, it should just care about what the data is. I've got some arbitrary thing `x` and a list of arbitrary things `xs`. I've got some `person` and a list of `people`. Using `head` and `tail` makes the rhs concerned with the structure of the incoming data. This becomes more of a problem if you have more complicated data structures on the lhs. One of the key elements of readable code is how easy it is to map your conceptual model onto source code onto executable code. Using head::tail wouldn't help new people grok the separation of structure on the lhs and manipulation on the rhs. All that said, it's such a minor point as to probably not really have any impact in this case. Just a bit of silly purist hand-waving.