Component Writer's Guide :: Enumerated Properties
There is no equivalent in PHP to Pascal enumerated types, so we have used a convention on the RPCL code but it's not enforced you use the same convention on your components.
To define several values for the BorderStyle property, we use defines:
// BorderStyles define('bsNone', 'bsNone'); define('bsSingle', 'bsSingle');
That way, if we use bsNone in your code, it gets translated to the string "bsNone", so an enumerated property is a string property and we can check their value against the constant we have defined.