testing whether the value of a variable is an array

[Ben Rubinstein]

Is there a clean way to test this?  Currently I'm using a pragmatic test:

    function isArray @v
      if v <> empty then return false
      return (the keys of v <> empty)
    end isArray

Is this reasonable?  Is there a more 'official' way?
 
  Ben Rubinstein               |  Email: benr_mc at cogapp.com
  Cognitive Applications Ltd   |  Phone: +44 (0)1273-821600
  http://www.cogapp.com        |  Fax  : +44 (0)1273-728866