Perl Programming/Keywords/when
The when keyword
when is a flow-control keyword that is used in the for and given statements.
The form EXPRESSION when EXPRESSION is used in the for statement, the form when EXPRESSION in the given statement that is similar to the C switch statement.
Please consider that given is considered highly experimental!
Syntax
EXPRESSION when EXPRESSION
when EXPRESSION
Examples
use v5.14;
for ($var) {
$abc = 1 when /^abcd/;
$def = 1 when /^efgh/;
$xyz = 1 when /^wxyz/;
default { $nothing = 1 }
}
}}
use v5.10.1;
given ($var) {
when (/^abc/) { $abc = 1 }
when (/^def/) { $def = 1 }
when (/^xyz/) { $xyz = 1 }
default { $nothing = 1 }
}
}}
use v5.14;
given ($var) {
$abc = 1 when /^abc/;
$def = 1 when /^def/;
$xyz = 1 when /^xyz/;
default { $nothing = 1 }
}
}}