The Hershey Fonts are given in a slightly unusual ascii code, based on the distance from the letter “R” in the alphabet. Our extensions use that code, translated slightly into numeric values, with different codes for move and lift (M, L).
See these two references for more about the original formats:
http://emergent.unpythonic.net/software/hershey
http://www.ghostscript.com/doc/current/Hershey.htm
You can certainly change the range of excluded characters as well, to make it accept any value that you like. If you need to type a character that isn’t in the ascii range, you’ll need to improvise somewhat, as the only input presently available is from the keyboard.
