An example script would help. but just by naked eye scan, I can see you are not using double =. In fact you should really use eq instead since you are doing character comparison. Secondly,this does not work to my knowledge(without the use of eval as noted above). You should get a scalar found where operator expected error. What are you trying to accomplish? Methods like this often indicate the need to rethink your design.

Let us know what you're trying to accomplish, post what you've tried... and then maybe we can help.