You can also use a global variable or a function library to achieve the same goal...the best thing to do is think about why you want to be doing this, how often it will be needed, and in how many scripts...that should direct you to the best route.
Oftentimes the quick fixes lead a developer into more trouble...if the parent script is something to be known regularly, create a function library ( or add these functions if your team already has a function library )
setParentScript( in_scriptName )
getParentScript( ) : var
in all your scripts that you need this functionality
include the library like this (assuming the name of the script is teamFunctionLibrary ):
this is clean and easy to read, it also reduces the amount of code you have to write later if you intend on doing this often (and that sort of thing is something that is needed often in many cases )
That's ONE way...as well as the others above...review the reasons for this task and then select according to your best judgement.