Field Types for Event and Command Parameters
Parameters for each type of event or command use one of the following field types:
Characters (letters, numerals, _ (underscore), and special characters used in macro-expansion)
Macro expansion can be used in fields of character type, as described in Using Macro Expansion for Character Fields. You can use the macros described in Macros for Parameter Values.
Boolean (allowable values are True and False)
Numeric (numerals 0 through 9)