parameter annotations (type, contract, etc.) in sweet.js

annotate.js

macro def {
  case $name:ident ( $($params:ident : $type:ident) (,) ...) $body => {
    // just throwing away the type annotation. The semantics of type
    // annotations left as an exercise to the reader :)
    function $name ($params (,) ...) $body
  }
}

def add (a : Number, b : Number) {
  return a + b;
}

add(1,2)

It'd be nice if this could be used to write pretty asm.