<wmmeta name="Title" value="The &lt;{perl}&gt; Directives" />
<wmmeta name="Section" value="03-proc_logic" />
<wmmeta name="Score" value="30" />
<wmmeta name="Abstract">
embed arbitrary perl logic
</wmmeta>

Arbitrary perl code can be executed using this directive.

It works like perl's ##eval## command; the return value from the perl block is
inserted into the file, so a perl code block like this:

<pre>
	&lt;{perl
	  &wmdollar;_ = '';
	  for my &wmdollar;fruit (qw(apples oranges pears)) {
	    &wmdollar;_ .= " ".&wmdollar;fruit;
	  }
	  &wmdollar;_;
	}&gt;
</pre>

will be replaced with the string '' apples oranges pears''.  Note that the
##&wmdollar;_## variable is declared as local when you enter the perl block,
you don't have to do this yourself.

If you don't like the eval style, you can use a more PHP/JSP/ASP-like
construct using the ##perlout## directive, which replaces the perl code text
with anything that the perl code prints on the default output filehandle, like
so:

<pre>
	&lt;{perlout
	  for my &wmdollar;fruit (qw(apples oranges pears)) {
	    print " ", &wmdollar;fruit;
	  }
	}&gt;
</pre>

Note that this is not STDOUT, it's a local filehandle called ##$outhandle##.
It __is__ selected as the default output handle, however, so just ##print##
without a filehandle name will work.

Also, it should be noted that ##perl## is a little more efficient than
##perlout##, so if you're going all-out for speed, you should use that.

<a href=$(perl)>&lt;{perl}&gt;</a> sections found at the top level of the
WebMake file will be evaluated during the file-parsing pass, as they
are found.

<a href=$(perl)>&lt;{perl}&gt;</a> sections embedded inside content chunks
or other tagged blocks will be evaluated only once they are referenced.

Perl code can access content variables and URLs using the <a
href=$(PerlCodeLibrary.pm.html)>library functions provided</a>.

The library functions are available both as normal perl functions in the
default ##main## package, or, if you want to write thread-safe or mod_perl-safe
perl code, as methods on the ##&wmdollar;self## object.  The ##&wmdollar;self##
object is available as a local variable in the perl code block.

A good example of perl use inside a WebMake file can be found in the
##news_site.wmk## file in the __examples__ directory.