CODEWITHSUNDEEP
perlvariablessubroutine
Jane Wilkie
Jane Wilkie

Reputation: 1743

Why does this line of Perl contain only a variable by itself?

I like perl the more I am getting into it but I had a question about a line I saw in a subroutine in a module I am looking through.

my $var = 1;
....
....
....
....
$var;

What throws me is just seeing that $var all by itself on a line. Is that just a roundabout way of returning 1 ?

Many thanks!

Jane

Upvotes: 3

Views: 204

Answers (2)

Ben Jackson
Ben Jackson

Reputation: 93770

In perl the value of a block is the value of the last expression in the block. That is just a shorthand for return $var.

EDIT: Purists point out that that blocks in general do not return values (like they do in Scala, for example) so you can't write:

my $x = if (cond) { 7 } else { 8 };  # wrong!

The implicit return value of a subroutine, eval or do FILE is the last expression evaluated. That last expression can be inside a block, though:

sub f {
    my $cond = shift;
    if ($cond) { 7 } else { 8 }  # successfully returns 7 or 8 from f()
}

There is the superficial appearance of the if/else blocks returning a value, even though, strictly speaking, they don't.

Upvotes: 6

Alan Haggai Alavi
Alan Haggai Alavi

Reputation: 74252

Quoting the last line of perldoc -f return:

In the absence of an explicit return, a subroutine, eval, or do FILE automatically returns the value of the last expression evaluated.

Upvotes: 6

Related Questions