Returns some if this context is defined, otherwise none.
Returns the value within the context if defined or else the value of default.
Returns true if a value is defined within the context.
Returns true if no value is defined within the context.
Returns true if a value is defined within the context.
Returns this context if defined or else the value of the alternative.
If the value has an a, return it; otherwise it must be
universally quantified.
Returns this context converted to the Maybe context.
Returns this context converted to the Option context.
Wraps a value
selfand provides methods related toOptional