Fetch the value of a substitution variable from a groovy rule

Summary

Attempting to get the value of a flag (which is a substitution variable) from a groovy rule

Content

Let me start by saying that my groovy knowledge is limited; I'm learning as needed.  I'm attempting to get the value of a substitution variable (flag 1 or 0) from a groovy rule.  If the flag is on/1 then execute a smart push.  I was told to set up a variable in calc manager and set the Default Value to the substitution variable (&VarName).  I cannot get the rule to validate.  I keep getting the following error.  'Error:The Groovy script failed to compile with internal error: Compile Error: