Perl Idiom

KirrilyRobert's favourite Perl idioms:


        $filename = param('filename') || "default";

        $filename ||= "default";


        my @a = qw(foo bar baz);


        print qq(with quotes);


        s{/usr/bin}{/usr/local/bin};


        my %named_params = @_;

The Englishy stuff:


        return unless $condition;

        s/a/b/ foreach @element;

        s/a/b/, s/foo/bar/ for $onevar, othervar;   # multiple subs to multiple vars

        open(F, "file") or die "Couldn't open 'file': $!";

        if ($conditionA or not $conditionB) ...

Others: EnPassant

...

KarlKnechtel's quick table lookup PerlIdiom:


        $result = ['foo', 'bar', 'baz']->[$selector];

MarkJasonDominus's favorite PerlIdiom:


        use Fcntl ':flock';

        flock *DATA, LOCK_EX|LOCK_NB or exit;

(When you want to be sure that at most one instance of a program is running at any time. The obvious solution: Have the program try to lock a file when it starts up; if the file is already locked, the process should exit. But what file? Idiomatic solution: Have the program lock the file that contains its own source code!)

CategoryIdiom