Identifiers (variable names, subroutine names, etc.) have 31 significant letters in PCC. Identifiers can contain the 26 Latin letters, digits, underscores `_', the decimal point `.' and the dollar sign `$'; they must start with a letter. Upper and lower case is not distinguished.
To avoid that your global identifier names (shared variables, subroutines, hooks, keymaps) clash with someone else's, use a prefix. For example, use your initials or the script name, like
Sub Check.Warn
in the `check.q' script. Identifiers starting with `CC$' are reserved for internal use in PCC.
Never ever use the shared variables A to Y in a script. Those are to be used by users in search queries, object labels, etc. When PCC computes the object labels, their values might get lost! If you wish to use them, explicitly declare them static or local using `Dim'.