=head1 NAME
perlfilter - Source Filters
-
+
=head1 DESCRIPTION
=head1 CONCEPTS
Before the Perl interpreter can execute a Perl script, it must first
-read it from a file into memory for parsing and compilation. (Even
-scripts specified on the command line with the C<-e> option are stored in
-a temporary file for the parser to process.) If that script itself
-includes other scripts with a C<use> or C<require> statement, then each
-of those scripts will have to be read from their respective files as
-well.
+read it from a file into memory for parsing and compilation. If that
+script itself includes other scripts with a C<use> or C<require>
+statement, then each of those scripts will have to be read from their
+respective files as well.
Now think of each logical connection between the Perl parser and an
individual file as a I<source stream>. A source stream is created when
C<decrypt> filter (which unscrambles the source before Perl parses it)
included with the source filter distribution is an example of a C
source filter (see Decryption Filters, below).
-
+
=over 5
package Debug;
use strict;
+ use warnings;
use Filter::Util::Call ;
use constant TRUE => 1 ;