Using Data::Dumper
Next comes some interesting Perl archaeology:
# use Data::Dumper; # print Dumper(\%page_data);
There, entombed by a layer of commenting, is a relic of a previous
era in the life of this script. When I had developed it sufficiently
far to have created the &load_pages
subroutine, which populated the
%page_data
hash, I wanted to see
what was being stuck in there. Enter the
Data::Dumper
module, a standard Perl module
written by Gurusamy Sarathy.
Data::Dumper
turns a data structure (like that
contained in the %page_data
HoH) into a chunk of
Perl code that would, if evaluated, re-create that original data
structure. This turns out to be really handy for development and
debugging because it lets us easily print out a snapshot of our
script’s data structure.
The Dumper
function that
Data::Dumper
gives us takes as its argument a
reference to the hash we wish to have represented as Perl code. In
the example here, we produce that reference by sticking the
backslash in front of the hash
name, like \%page_data
, as we learned how to do
back in Chapter 11.
Here’s an example of what the Dumper
function might print out:
$VAR1 = { '/w1/s/socalsail/cyberfair/leader/government/al_gore.html' => { 'name' => 'Al Gore', 'title' => 'Al Gore's Leader Profile', 'type' => 'cf', 'content' => '<H2>Al Gore</H2> <P>By: John C.</P> <P>Al Gore was born on March 31, 1948, in Washington, D.C.</P>', 'writer' => 'nakasone/johnc', 'photographer' => 'nakasone/johnc' }, (etc.)
Here’s how to interpret ...
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