= Missing Constant

If a constant is missing it is because it was not found
in either the demos scope, the applique or the toplevel.

  begin
    UnknownConstant
  rescue => err
    # no colon means toplevel
    /[^:]UnknownConstant/ =~ err.message
  end

A constant defined in the applique is visible.

  APPLIQUE_CONSTANT.assert = true