draws a building flowchart from makefile

makefile-graphviz.pl

#!/usr/bin/env perl
#
# makefile-graphviz.pl - draws a building flowchart from makefile
#
# Draws a buildidng flowchart from makefile using Makefile::GraphViz.
#
# Usage Example:
# % ./makefile-graphviz.pl Makefile Makefile.png
#
# Seungwon Jeong <seungwon0@gmail.com>
#
# Copyright (C) 2013 by Seungwon Jeong
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see
# <http://www.gnu.org/licenses/>.

use perl5i::2;

use Makefile::GraphViz;

my ( $input_file, $output_file );

given ( scalar @ARGV ) {
    when (0) {
        $input_file  = 'Makefile';
        $output_file = 'Makefile.png';
    }

    when (1) {
        $input_file  = $ARGV[0];
        $output_file = 'Makefile.png'
    }

    when (2) {
        $input_file  = $ARGV[0];
        $output_file = $ARGV[1];
    }

    default {
        say "Usage: $PROGRAM_NAME [INPUT_FILE [OUTPUT_FILE]]";
        exit 2;
    }
}

my $parser = Makefile::GraphViz->new;

$parser->parse($input_file);

my $gv = $parser->plot_all;

$gv->as_png($output_file);