SQL*Plus Worksheet DEFINE command

Question

**I hope this is the correct place to put this, I don't see a forum for SQL*Plus Worksheet.**
I am having some trouble with SQL*Plus Worksheet. The following call to a package works fine,
EXECUTE package_name.procedure_name ('string_name');where it is required that my argument passed to the procedure needs the quotes as part of the string. However, when I try to use a variable instead of hardcoding the 'string_name' value, ie
DEFINE string_name = 'string_name';
EXECUTE package_name.procedure_name (&string_name);I get an error message saying that my variable needs to be defined (the call was made passing the string w/o the quotes). How can I pass the entire string, quotes and all, to the package call? I've tried concatenating them to the variable in the DEFINE and EXECUTE commands but I can't seem to come up with the correct syntax.
Does anybody know how to do this?

Answer 1

Here is the current SQL*Plus Worksheet command, and output (works):
EXECUTE amanda.role_executor.drop_role ('read_only');
PL/SQL procedure successfully completed.So, now I try to pass the argument as a variable, instead of hardcoding the value to the call:
DEFINE role_name = 'read_only';
EXECUTE amanda.role_executor.drop_role (&read_only);
BEGIN amanda.role_executor.drop_role (read_only); END;
ERROR at line 1:
ORA-06550: line 1, column 39:
PLS-00201: identifier 'READ_ONLY' must be declared
ORA-06550: line 1, column 7:
PL/SQL: Statement ignoredAs you can see when I try to pass the string as a variable the single quotes get lost. How can I concatenate the single quotes to the string? I've tried everything I can think of but apparently Worksheet doesn't like the || symbols.