Option
Deprecated type (since 2021.1.23, to be removed in 2023.3.0)
The Option type will no longer be supported. Please use Optional instead.
Type
NPL does not have null, but in practice it is not always possible to assign meaningful values to everything
immediately. For such cases there is Option<T>.
Options are instantiated using optionOf.
Accessing the value of an Option<> is accomplished through getOrFail() or getOrElse(), whereas inspecting whether
it contains a value is accomplished through isPresent() (see Methods section below).
Note that it is considered best practice to always initialize variables with meaningful values when possible.
Methods
computeIfAbsent
computeIfAbsentDeprecated: Use Optional
<function> Returns the value of an option if present, or returns a computed result if empty. The computation is not invoked if the option is not empty, making this is a lazy alternative to Option<T>.getOrElse.
Receiver
Option<T>
Type Arguments
T - the option's payload
Arguments
default - () -> T - function or closure that returns the value in case the option is empty
Returns
T - the option's value if present, or the computed result if empty
Usage
// If the Option is empty, the value lazily
// computed by the provided function is returned.
optionOf<Number>().computeIfAbsent(function() -> 42) == 42
// If the Option is *not* empty,
// the Option's payload is returned.
optionOf(21).computeIfAbsent(function() -> 42) == 21
getOrElse
getOrElseDeprecated: Use Optional
<function>
Returns the value inside the option if present, or the default value otherwise.
Receiver
Option<T>
Type Arguments
T
Arguments
default - T - value to return if option contains no value
Returns
T - the value inside the option if present, otherwise default
Usage
optionOf<Number>(42).getOrElse(1) == 42
optionOf<Number>().getOrElse(1) == 1
getOrFail
getOrFailDeprecated: Use Optional
<function>
Returns the value inside the option if present, or causes runtime error 27 -- Empty option otherwise.
Receiver
Option<T>
Type Arguments
T
Returns
T
Usage
optionOf<Number>().getOrFail() // Throws a run-time exception
isPresent
isPresentDeprecated: Use Optional
<function>
Returns true if a value is present in the option, and false otherwise.
Receiver
Option<T>
Type Arguments
T
Returns
Boolean - true if a value is present in the option, otherwise false
Usage
optionOf<Number>(42).isPresent() == true
optionOf<Number>().isPresent() == false
Inherited methods
toText
<function>
Obtain the Text representation of this.
Receiver
T
Type Arguments
T
Returns
Text - the Text representation of this
Usage
Converts an Option<T> to Text.