Would you mind weaving it into my code so I can see for myself?

(Note: The following provides answers already given in essence by LanX, but it at least also provides an example of sorts and so may be helpful.)

... how would I use [data dumper] to see the data and the structure of $ua and $res?

Untested: 

use Data::Dumper;
...
my $ua = LWP::UserAgent->new;
print Dumper $ua;
...
my $res = $ua->get(...);
print Dumper $res;
...

[download]
Please see Data::Dumper. (Note: Be prepared for a lot of data to be dumped from some object references!)

Also a point of confusion: is
    $ua->show_progress
the same thing as
    $$ua{show_progress}
?

It is not. The expression  $ua->show_progress invokes (without any arguments) the method  show_progress() in the class (or a superclass) of which  $ua is an object reference.

The expression  $$ua{show_progress} attempts to access the value of the  'show_progress' key in the anonymous hash to which  $ua is presumed to be a reference; it is an error if  $ua is not a hash reference. This expression is the same as the form  $ua->{show_progress} which is preferred (properly, IMHO). 

c:\@Work\Perl>perl -wMstrict -le
"{ package Foo;
   use Data::Dump qw(pp);
   ;;
   sub new {
     my $class = shift;
     return bless { show_progress => 'not so fast',  @_, } => $class;
     }
   sub show_progress {
     my $self = shift;
     print 'Real Thing: ', pp $self;
     }
   }
 ;;
 my $object_reference = Foo->new(foo => 'bar',  hi => 'lo');
 ;;
 $object_reference->show_progress;
 print 'A: ', $$object_reference  {show_progress};
 print 'B: ',  $object_reference->{show_progress};
"
Real Thing: bless({ foo => "bar", hi => "lo", show_progress => "not so
+ fast" }, "Foo")
A: not so fast
B: not so fast

[download]
I'm using Data::Dump in this example instead of Data::Dumper because I like its output formatting better; the latter is core, the former is not.

Give a man a fish:  <%-{-{-{-<

In reply to Re^3: data dumper question by AnomalousMonk
in thread data dumper question by Todd Chester

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