Subroutine reference

vinoth.ree has asked for the wisdom of the Perl Monks concerning the following question:

 sub testing(){
    foreach(@_){
        print $_;
    }
}

my $subref=\&testing(1,2,3,4,6);
print Dumper $subref;
my $subref=\&testing;
[download]

In the above code I tried to get the reference to a subroutine, When I try the first one with parameter it called the function and the return value's reference is saved in the $subref variable

In the second one I tried without parameter the subroutine's reference saved in the $subref variable

How these two interpreted differently in Perl?

Comment on Subroutine reference Download Code

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Re: Subroutine reference by ikegami (Patriarch) on Mar 13, 2009 at 05:15 UTC
In the second, you have the reference operator followed by a subroutine name. This returns a reference to the named subroutine. In the first, you have the reference operator followed by a subroutine call. Subroutine calls evaluate to the value returned by a call to the subroutine. You're making a reference to that. The solution is to wrap the call in a subroutine that takes no argument, and take a reference to that subroutine instead. `my $subref = sub { testing(1,2,3,4,6) };` [download]	[reply] [d/l]
Re: Subroutine reference by lakshmananindia (Chaplain) on Mar 13, 2009 at 04:45 UTC
`sub greet { print "hello \n"; } $rs = \&greet; # Create a reference to subroutine greet $rs = \&greet();` [download] It calls greet and produces a reference to its return value. --Lakshmanan G. Your Attempt May Fail, But Never Fail To Make An Attempt	[reply] [d/l]
Re: Subroutine reference by nagalenoj (Friar) on Mar 13, 2009 at 04:45 UTC
Dear monk, It is not okay to use parentheses when taking a subroutine reference. So, avoid that statement. Subroutine references	[reply]
Re: Subroutine reference by Anonymous Monk on Mar 13, 2009 at 07:22 UTC
B::Deparse can be illuminating `$ perl -MO=Deparse,-p temp.pl sub testing () { foreach $_ (@_) { print($_); } } (my $subref = \(&testing(1, 2, 3, 4, 6))); print(Dumper $subref); (my $subref = (\&testing)); __DATA__ temp.pl syntax OK` [download]	[reply] [d/l]