default namespace = "http://www.idiominc.com/opentopic/vars"

vars =
  ## Static string variables
  element vars {
    variable*
  }
param =
  ## Parameter reference
  element param {
    ## Parameter name
    attribute ref-name { text }
  }
variable =
  # Static string variable
  element variable {
    ## Variable name
    attribute id { text },
    mixed { (variable-ref | param)* }
  }
variable-ref =
  ## Variable reference
  element variable {
    ## Variable reference name
    attribute id { text }
  }
start = vars