> You'll find that while maps are in theory lists of vector pair They aren't. Wh...

Anderkent · on July 31, 2014

    user=> (pr-str (seq {:a 1 :b 2}))
    "([:a 1] [:b 2])"
    user=> (vector? (first (seq {:a 1 :b 2})))
    true

It looks like a vector, it quacks like a vector...

eddieplan9 · on July 31, 2014

    user=> (doc vector?)
    -------------------------
    clojure.core/vector?
    ([x])
      Return true if x implements IPersistentVector
    nil

So `MapEntry` implements `IPersistentVector`, but is not a vector. It does not make sense to have an empty `MapEntry`, so IMHO the behavior implemented is valid.

Anderkent · on July 31, 2014

'Hey, if I peek under the abstraction, it all makes sense'. Obviously. The code does what it's written to do. That doesn't make such leaky abstractions okay. `vector?` is, AFAIK, the way to check if something is a vector, and if empty doesn't work on some `vector?`s, then i can't trust it.

empty mapentry returning nil is meh. If it returned an empty vector it'd be what you want 99% of the time.