Colon

Colon 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

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, Named Parameters, Scope Resolution Operator ::