Question

This might seem like a stupid question but it’s been a long day. I’m an adapting some Perl code for another use and I ran across this syntax:

my @request;

#... fill the array with stuff...

my $reply = $service->call('requestMessage' => @request, $header);

That method call seems implausible, if => is just a special kind of comma and @request gets interpolated into the list.

Is it actually equivalent to:

my $reply = $service->call('requestMessage' => \@request, $header);

What’s going on here?

EDIT: Thanks for the answers. I am well aware of the difference between pass by value and pass by reference. I was asking if an apparent pass by value was being converted into a pass by reference. Apparently not. Thank you all for answering.

Answer 1

The code in question:

my $reply = $service->call('requestMessage' => @request, $header);

is not equivalent to this:

my $reply = $service->call('requestMessage' => \@request, $header);

It is, as you surmised, equivalent to this:

my $reply = $service->call('requestMessage', @request, $header);

Sometimes, the “fat comma,” as => is known, is used to indicate a relationship between positional parameters. For example, the link between the method name some_method and its intended @arguments in this code:

$server->distribute_across_nodes(some_method => @arguments);