[plt-scheme] How to replace a Unicode string in the definitions with the result of evaluating it?

Hi folks,

In DrScheme I would to be able to type:

"\u266C"

in the definitions window, and with the cursor here:

"\u266C"|

execute some code that would replace the entire string with the result
of evaluating it in the repl (but without the double quotes):

♬

I am not sure of the best way to go about evaluating the string. I am
going to start by investigating namespaces. What is the best way to do
this?

I figured that I can find the editor manipulation in the DrScheme
source to do the replacement itself.