Colon

Colons are used in a variety of situations :

• With named parameters, to separate the name from the value

• With labels, for goto

• With ternary operator, separated or not from the question mark

The double colon is a distinct operator.

<?php

goto there;
there:

foo(a: 3); //

$b = $a ? 'a' : 'b';
$c = $c ?: 'a';

?>

Related : Goto, Ternary Operator, Coalesce Operator, Coalesce Operator, Named Parameters, Scope Resolution Operator ::