| PackageDescription | The 'ReturnValue' class provides a very simple wrapper around a value so
you can tell if it's a success or failure without taking pains to examine
the particular value. Instead of using exceptions, you inspect the class of
the object you get back. Errors and successes flow through the same path.
This isn't particularly interesting for success values, but can be helpful
with multiple ways to describe an error.
* success
Create a success object
* error
Create an error object
* value
The value that you'd normally return. This class doesn't care what it is.
It can be a number, string, or reference. It's up to your application to
figure out how you want to do that.
* description
A long description of the return values,
* tag
A short tag suitable for switching on in a 'given', or something similar.
* success_type
Returns the class for success objects
* error_type
Returns the class for error objects
* is_success
Returns true is the result represents a success
* is_error
Returns true is the result represents an error |