This class provides a text editor specialized for editing
Ptlang files.
Ptlang is the preprocessor language used to define Ptolemy stars.
Its editor is invoked automatically when opening any file with a
.pl
extension
in its name.
The EditPtlang class is derived from the
EditCpp class, the C++ editor, and
therefore inherits all of its features.
At the moment, it does little more than color Ptlang keywords.