travis

A little Clojure challenge inspired by Let over Lambda.

Write a macro (you can try a function, but it's impossible) that accepts four arguments:

1. an expression that returns a number
2. something to return if that number's negative
3. something to return if that number's zero
4. something to return if that number's positive

Here's the signature: (defmacro nif [expr neg zero pos] ...)