My use case is to use the script name to construct the test data path of excel sheet. For ex: I create a test script as such TC01_CreateOrder then I will use the test script as CreateOrder to construct the excel file name. C:\Project\TestData\<testscripname.xls>
I'm not super familiar with VBScript but I don't think this is something that you can do.
If you're associating a known excel sheet with a known function / sub though, why do you need this? Just store the you need excel path in your function / sub. Unless I am missing something from your explanation.