Turning a template into Perl code means turning a
template inside out: typical templating systems use
a mixture of HTML and Perl (or Perl and "something
else", which isn't necessarily HTML), where the Perl
is "inside" the HTML. Like this, sort of:
<b>Name: </b><% $name %><br>
The HTML is the outer layer, and the Perl is contained
within special sections marked off by some delimiters.
In this case, <% and %>.
Most templating systems will turn something like the
above into this:
$_out->("<b>Name: </b>");
$_out->( $name );
$_out->("<br>");
Imagine $_out is a subroutine reference that is basically just
my $_out = sub { print @_ }
So essentially, "turning a template into Perl code" has
created a piece of Perl code with a bunch of print statements,
which is what you might have written if you hadn't used templates
at all. This is what I mean by turning the template inside out: you
have taken a template that was HTML with embedded Perl, and have
turned it into a Perl script with embedded HTML.
The advantage to Perl code is that Perl code is fast. :)
Ie. if you have a block of Perl code, you can execute it directly;
you don't have to parse it as a template. So you can store it in
this intermediate Perl script form, and then just run it again
without reparsing the original template.
This is a relatively standard way of caching templates for many
Perl templating engines. And obviously, this is just
a small example, but it shows the basics of how it
works. | 