In Harlequin Dylan 1.2 and 2.0 beta 2 the 'print-message' generic
function exported from the format library is sealed. In Gwydion Dylan
it is open. Some of the Gwydion Dylan code (parsergen for example)
adds methods to print-message and will not work in HD as a result.

Reading the help for print-message under HD doesn't say whether it
should be sealed or not but it does say:

  "This function exists to define the behavior of the %S format
  directive and to allow users the ability to extend the %S
  directive."

This gives the impression that it should be open. Generics like
print-object are open as expected.

Should print-message be open or sealed?

Chris.