It depends how the special characters are supposed to be rendered. For instance, with the pandoc HTML generator, i'm using HTML unicode syntax (which of course works for XML too)
"""
* my address: ville rantanen☺helsinki fi
"""
Someone wiser may answer about the script language parsing itself.
I can recognize that here for example, the script runs, but the contents of the output is not correct
c=StringInput(content="λ")