strange behavior of parenthesis

mosh has asked for the wisdom of the Perl Monks concerning the following question:

Hi Holly Monks !

I need an explanation of 2 similar code sections but with different results:

First one:

our $AUTOLOAD = "aaa::bbb::ccc";

my ($func) = $AUTOLOAD =~ /.*::(.*)$/;

print "$func\n";        ## ccc
print "$AUTOLOAD\n";    ## aaa::bbb::ccc
[download]

Second:

our $AUTOLOAD = "aaa::bbb::ccc";

my $func = $AUTOLOAD =~ /.*::(.*)$/;

print "$func\n";        ## 1
print "$AUTOLOAD\n";    ## aaa::bbb::ccc
[download]

The only different between the 2 section of code is the parenthesis surrounded the $func

What's the explanation for it?

Thanks,
Mosh.

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Re: strange behavior of parenthesis by holli (Abbot) on Jul 11, 2005 at 10:12 UTC
In list context the =~ operator returns the catched parts (those in between braces in the regex). In scalar context it returns the number of catched parts. The braces around $func induce list context. Should be clear now, no? holli, /regexed monk/	[reply] [d/l]
Re^2: strange behavior of parenthesis by broquaint (Abbot) on Jul 11, 2005 at 11:12 UTC
Further to that, you can find this documented in `perlop` under the m/PATTERN/cgimosx subsection of the Regexp Quote-Like Operators section: `If the /g option is not used, perlop in a list context returns a list consisting of the subexpressions matched by the parentheses in the pattern, i.e., ($1, $2, $3...). (Note that here $1 etc. are also set, and that this differs from Perl 4's behavior.) When there are no parentheses in the pattern, the return value is the list (1) for success. With or without parentheses, an empty list is returned upon failure.` HTH `_________ broquaint`	[reply]
Re^2: strange behavior of parenthesis by mosh (Scribe) on Jul 11, 2005 at 11:00 UTC
So, it catches only the (.*) ? How come ?	[reply]
Re^3: strange behavior of parenthesis by Ultra (Hermit) on Jul 11, 2005 at 11:04 UTC
So, it catches only the (.) ?* What else? Dodge This!	[reply]
Re: strange behavior of parenthesis by ysth (Canon) on Jul 11, 2005 at 15:49 UTC
This is a scalar assignment, and the right side is evaluated in scalar context: `$foo = ...` [download] These are list assignments, and the right side is evaluated in list context: `($foo) = ... @foo = ... %foo = ... @foo{LIST} = ... @foo[LIST] = ... () = ...` [download] What the match operator returns depends on success of the match, context, presense of capturing parenthesis, and whether there's a //g flag. See the doc for details.	[reply] [d/l] [select]