property _ArgvUserError : 10000 -- error code used to indicate the shell script's user supplied invalid command line options (errors due to bugs in invalid option/argument definitions supplied by shell script author use standard AS error codes); need to decide what's a sensible code to use and document it in SDEF (unfortunately, `on error number ...` blocks only accept literal integer (for pattern matching) or identifier (for assignment) and don't allow a command as parameter, so there's no way to supply library-defined error numbers as 'named constants' via library-defined commands, e.g. `on error number (command line user error)`, that return the appropriate number)