a Lightened Build tool with bash script

build.s

action "say"
  desc "say hello" #action description
  #bash script here
  echo "Hello world"


  echo "Blank line doesn't stop block"

#Comment are unheeded
echo "executed out of function"

action "bye"
    echo "byebye"

compile.pl

#!/usr/bin/env perl -w
use strict;

use Digest::SHA;

our $CACHE_DIR = "./";
our $BASH_HEADER="#!/bin/bash\n\n";

sub print_header
{
    my ($desc) = @_;
    print $desc $BASH_HEADER;
}

sub print_usage
{
    my ($desc, %actions) = @_;

    print $desc "function usage() {\n";
    print $desc "\techo \"usage: $0 <command>\"\n";
    print $desc "\techo \"\"\n";
    print $desc "\techo \"commands:\"\n";
    while( my ($action, $description) = each(%actions) ) {
        print $desc "\techo \"      $action - $description\"\n";
    }
    print $desc "}\n\n";
};

sub is_updated
{
    my $sha = Digest::SHA->new(256);
    $sha->addfile($_[0]);
    my $digest_name = $sha->hexdigest;

    if(! -f "$CACHE_DIR/$digest_name") {
        return "$CACHE_DIR/$digest_name";
    }
    else {
        return undef;
    }
};

sub compile
{
    my ($script, $compiled) = @_;
    my $isBlock = 0;
    my %actions = ();
    my $current_action = "";
    my $ligne;

    open(my $SRC,"< $script");
    open(my $DEST, "> $compiled");

    print_header($DEST);

    while(defined( $ligne = <$SRC>)) {

        if( $ligne =~ m/^\s*action\s"([^"\s]+)".*$/ )
        {
            if($isBlock)
            {
                print $DEST "}\n\n";
                $isBlock=0;
            }

            $current_action=$1;
            $actions{$current_action} = "No description available";
            print $DEST "function $1 {\n";
            $isBlock=1;
        }
        elsif( $ligne =~ m/^\s*desc\s"([^"]+)".*$/ )
        {
            if($current_action ne "")
            {
                $actions{$current_action} = $1;
            }
        }
        elsif ($ligne !~ m/^\s*#.*/ && $ligne !~ m/^$/)
        {
            if($isBlock && $ligne =~ m/^[^\s].*/)
            {
                print $DEST "}\n\n";
                $isBlock=0;
                $current_action = "";
            }

            print $DEST $ligne;

            if($ligne !~ m/\n$/)
            {
                print $DEST "\n\n";
            }
        }
    }

    if($isBlock)
    {
        print $DEST "}\n\n";
        $isBlock=0;
        $current_action = -1;
    }

    print_usage($DEST,%actions);

    print $DEST "command=\"\${1}\"\n";
    print $DEST "case \"\$command\" in\n";
    foreach my $action (keys(%actions)) {
        print $DEST "\t$action)\n";
        print $DEST "\t\tshift;\n";
        print $DEST "\t\t$action \$@;\n";
        print $DEST "\t\t;;\n";
    }
    print $DEST "\t*|help)\n";
    print $DEST "\t\tusage;\n";
    print $DEST "\t\t;;\n";
    print $DEST "esac\n\n";

    close($DEST);
    close($SRC);
};

my $compiled;
if( defined( $compiled=is_updated("build.s") ) ) {
    compile("build.s", $compiled);
    chmod 0755, $compiled;
}
exec $compiled, @ARGV;

gistfile1.sh

script execution:

$ ./compile.pl [<command>]

with <command>: help or one of defined action in build.s

--------------------------------------------------------

result of the compilation:

#!/bin/bash

function say {
  echo "Hello world"
  echo "Blank line doesn't stop block"
}

echo "executed out of function"
function bye {
    echo "byebye"
}

function usage() {
	echo "usage: ./compile.pl <command>"
	echo ""
	echo "commands:"
	echo "      bye - No description available"
	echo "      say - say hello"
}

command="${1}"
case "$command" in
	bye)
		shift;
		bye $@;
		;;
	say)
		shift;
		say $@;
		;;
	*|help)
		usage;
		;;
esac