gistfile1.rb

foo = routine
  lookup = routine
    # All lookups after foo are put into @
    # so 'foo bar baz' would give you @ = (bar baz)
    out = @0
    # The default implementation does a reduce() with dereferencing, something like this
    @.prepend(this)
      reduce(@0)
        @2(@0[@1])
          out(@0)
  
  foo bar baz # will call our lookup with `foo