I am also a long-time lurker / First time responder, so hopefully I'll
answer acceptably per the email-list conventions...
I will assume that some of the basic references are available to you (or
that others will cite them correctly... as they appear to be doing; many
responses so far.)
Anyway, *syntax* is relatively easy to answer; *why* someone might have
written such a thing, not always as much...
I would personally interpret this question in the way I would normally see
it: "Why is someone putting parentheses around these variables?"
When confronted with questions like this (and I often encounter obscure
Perl in my daily work, so that's fairly common here) I start by directing
the questioner to two things:
google site:perlmonks.org parentheses variable
google site:stackoverflow.com parentheses variable
My justification for this is, when trying to figure out why one piece of
code is a certain way, it helps to go to the sites where people who write
code share what they're doing, and other people comment knowledgeably about
it.
(I'm sure there are other sites that others recommend; these are just the
two I've found most useful.)
Scanning through the results, I might use them to answer someone who asked
the question the way I wrote it... more-or-less this way:
Left-hand-side: Putting parentheses around a scalar (or a set of scalars)
is a way to assign values to everything in the list all at the same
time (even if it's just have one thing getting one assignment).
Right-hand-side: Putting parentheses around an array is shorthand for
getting the first element of the array (by converting the elements into a
list -- changing from scalar to list context)
...in the same way that leaving the parentheses off and not specifying
a single element, will return the number of elements in the array.
Further, it's worth noting that putting parentheses around a single scalar
on the left-hand-side of an assignment (a list of one thing)... is subtle.
For example, in
http://stackoverflow.com/questions/10031455/perl-using-my-with-parentheses-and-only-one-variable
I see that http://stackoverflow.com/users/2766176/brian-d-foy (who
answers these types of questions for a living) is essentially saying on one
hand that he does it just because he's used to typing "my (" and some
stuff, and then ");" and that just having one thing isn't a problem; but he
also notes farther down
http://perldoc.perl.org/perlfaq4.html#What-is-the-difference-between-a-list-and-an-array%3f
for completeness.
Hope this helps! -Steve Kaftanski, MadMongers.org (Madison.pm Wisconsin).
On Thu, May 29, 2014 at 3:20 PM, James Kerwin <jkerwin2...@gmail.com> wrote:
> Hello all, long time lurker, first time requester...
>
> I have a Perl exam tomorrow and came across a question that I just cannot
> find an answer to (past paper, this isn't cheating or homework etc.).
>
> Explain the difference between:
>
> ($test)=(@test);
>
> And
>
> $test=@test;
>
> If anybody could shed any light on this I'd be very grateful.
>
> Thanks,
> James.
>
