If fa
has an a
, return it; otherwise it must be universally
quantified.
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 true
if a value is defined within the context. This is an alias for isDefined
.
Returns given context if it is defined or else the value of the alternative
.
Returns this context converted to the Maybe
context.
Returns this context converted to the Option
context.
Abstraction over a container/context which may or may not provide a value.
the container/context type
syntax.OptionalOps