You had:

$webcrawler is a scalar. If it were a scalar code ref, you could do &$webcrawler( format => 'text' ), but it looks to be to be a WWW::Mechanize object. So, what you have is a scalar, then two more scalars in parenthesis.

You need some sort of operator between the '$webcrawler' and the parenthesis. More than likely, based on the parentheis, you're missing a method call:

So, what method call takes a hash as its argument, and one of the keys is format? We look at the documentation for WWW::Mechanize, and search for the string 'format', and we find the following:

So, I can only guess that you should have written:

The following code may do something like what you are trying to achieve:

use warnings;
use strict;
use WWW::Mechanize;
use HTML::TreeBuilder;

my $webcrawler = WWW::Mechanize->new();
my $page = $webcrawler->get ('http://perlmonks.org/?node_id=479598');
my $tree = HTML::TreeBuilder->new_from_content ($page->as_string ());
print $tree->as_text ();
[download]