Syntax and gui scripting can you do it

Ok I have a question I have been wondering. You can use [] freely in variables because the variable is evaluated as a string and the brackets get removed. Like the example code

%strpart = "left";
%strleftdirection = "blah whatever you want here";
echo(%str[%strpart]direction);

the echo would print the contents of the variable %strleftdirection I am wondering if you can piece names toghter like this for other things like names of guictrls or is it just limited to variables.