#when EXPR BLOCK

#when BLOCK

when is analogous to the case keyword in other languages. Used with a foreach loop or the experimental given block, when can be used in Perl to implement switch/case like statements. Available as a statement after Perl 5.10 and as a statement modifier after 5.14. Here are three examples:

    use v5.10;
    foreach (@fruits) {
        when (/apples?/) {
            say "I like apples."
        }
        when (/oranges?/) {
            say "I don't like oranges."
        }
        default {
            say "I don't like anything"
        }
    }

    # require 5.14 for when as statement modifier
    use v5.14;
    foreach (@fruits) {
	say "I like apples." 	    when /apples?/; 
	say "I don't like oranges." when /oranges?;
        default { say "I don't like anything" }
    }

    use v5.10;
    given ($fruit) {
        when (/apples?/) {
            say "I like apples."
        }
        when (/oranges?/) {
            say "I don't like oranges."
        }
        default {
            say "I don't like anything"
        }
    }

See "Switch statements" in perlsyn for detailed information.

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