Page 4 shows a naming convention for procedure parameters:
and so on.
There is no notation convention for characters and strings. It feels a bit funny that the document uses this notation and then x, x_1, x_2 are used for reals, but then uses "char_1" and "char_2" for characters.
WG1 decided to just add the existing names to the master list.
Added a few more and alphabetized.