Polymorphic return values are really useful. Often, we just want to know if something worked or not. Other times, we'd like to know what the error text was. Still others, we may want to know what the error code was, and what the error properties were. We don't want to handle objects or data structures for every single return value, but we do want to check error conditions in our code because that's what good programmers do.
When functions are successful they may return true, or perhaps some useful data. In the quest to provide consistent return values, this gets confusing between complex, informational errors and successful return values.
This module provides these features with a simple API that should get you what you're looking for in each contex a return value is used in.