Note: information on this page refers to Ceylon 1.0, not to the current release.

exists operator

The non-associating, unary postfix exists operator is used to test its operand for nullness.

Usage 

void m(Integer? num) {
    Boolean haveNum = num exists;
}

Description

Definition

The meaning of exists is defined as follows:

if (exists lhs) true else false

Polymorphism

The exists operator is not polymorphic.

Type

The result type of the exists operator is Boolean.

Note

Do not to confuse the exists operator described here and which takes postfix form attribute exists with the exists condition used in if, assert and while statements and which takes the prefix form exists attribute.

See also