File Coverage

blib/lib/Simple/Filter/Macro.pm

Criterion	Covered	Total	%
statement	9	11	81.8
branch			n/a
condition			n/a
subroutine	3	3	100.0
pod			n/a
total	12	14	85.7

package Simple::Filter::Macro;

# Set the VERSION.
$VERSION = "0.08";

# Load the Perl pragmas.
use strict;
use warnings;

# ---------------------------------------------------------------------------- #
# Simple::Filter::Macro                                                        #
#                                                                              #
# In the following code the predefined default input string variable $_ is     #
# used twice. The outer value of $_ is the content from the module. The inner  #
# value of $_ is the content from the script. The Perl function caller() is    #
# used as follows. For example one can write my ($package, $filename, $line)   #
# = caller($i) where $i is the level in calling of interest. The elements of   #
# the array can be reached as it is known by e.g. caller(0)[0] which results   #
# the package name of calling level 0. C returns the data from the  #
# module and caller(6) returns the data from the script. Data are filename and #
# line of appearance in source code. To work as expected the module terminator #
# 1; has to be stripped from the module content. In the Perl function join()   #
# the newline string "\n" is used as separator between module content and      #
# script content. The Perl function q() simply interprets the merged content   #
# as a single-quoted string. The Perl function sprintf() creates the new       #
# content of the compiled file as a multi-line string.                         #
# ---------------------------------------------------------------------------- #

# Outer filter starts here.
use Filter::Simple::Compile sub {
    # Remove the module terminator from the module content.
    $_ =~ s/1;\s//g;
    # Create the modified script content.
    $_ = sprintf(
        # Create a single-quoted string for output.
        q(
            # Inner filter starts here.
            use Filter::Simple::Compile sub {
                # Concatenate content from module and script.
                $_ = join("\n",
                    "#line %s %s", "%s", "#line %s %s",
                    $_, # Script content.
                );
            };
            # Inner filter ends here.
            1;
        ), (caller(5))[2], (caller(5))[1],
           $_, # Module content.
           (caller(6))[2], (caller(6))[1]
    );
};
# Outer filter ends here.
1;

__END__