Incorrect pattern matches in "macro" macro

Created by: andreypopp

Hello,

First — Sweet.js is super awesome, thanks!

I'm trying to write a simple macro which will produce an object literal from a list of k-v pairs but passes everything else as-is:

attributes(id) // id
attributes({}) // {}
attributes(k: v, a: 1) // {k: v, a: 1}

Currently my macro looks like this:

macro attributes {
  case {_()} => {
    return #{null}
  }
  case {_($($name:ident : $val:expr) (,) ...)} => {
    return [makeDelim('{}', #{$($name: $val) (,) ...})]
  }
  case {_($any:expr)} => {
    return #{$any}
  }
}

But somehow attributes(id) matches the second case which is, I believe, wrong.

P.S. this macro is part of the bigger story, which is why I have a special case producing null for empty arg list.