Subroutine prototype

[sedawk]

What does the ";$" in the following subroutine prototyping?

sub doIt(;$) {
    use strict;
    my $src = @_ ? : shift : "";
    ....
}

 

[rharsh]

Everything before the semi-colon is required (in this case, there's nothing) everything after it is optional.

So $src either gets set to whatever is passed to the sub or if nothing is passed in it's set to "" (rather than the default undef.)

 

[KevinADC]

More than you may ever want to know about prototypes:

http://perldoc.perl.org/perlsub.html#Prototypes

the semi-colon just seperates mandatory and optional arguments passed to the sub.

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- Kevin, perl coder unexceptional!