Catalyst.Optional – catalyst-1 – Vala Binding Reference

Content:

Properties:

public bool is_present { get; }

Whether or not the the optional contains a value.

public T value { get; }

The value held by the optional.

Creation methods:

public Optional.empty ()

Creates an empty instance.

public Optional.of (owned T value)

Creates an optional from a non-null value. It is an assertion failure to provide a null value.

public Optional.of_nullable (owned T value)

Creates an optional from a potentially null value. If the provided value is null, the optional will be empty.

Methods:

public Optional<T> filter (Predicate<T> predicate)

Filters the value based on the given predicate.

public Optional<A> flat_map<A> (MapFunc<Optional<A>,T> map_func)

Applies the given mapping function if the value is present.

public Optional<A> map<A> (MapFunc<A,T> map_func)

Applies the given mapping function if the value is present.

public T or_else (T other)

Returns the value if present, otherwise the other.

public T or_else_get (SupplyFunc<T> supplier)

Returns the value if present, otherwise the value supplied by the supplier function.

public T or_else_throw (SupplyFunc<Error> supplier) throws Error

Returns the value if present, otherwise throws an error.

Inherited Members:

All known members inherited from class GLib.Object

Optional