#!/usr/bin/perl -w

# This is gimp-mkenums, a perl script based on glib-mkenums.
# It can be used just like glib-mkenums but offers one extra
# feature: The keyword "desc" is recognized in trigraphs and
# allows to specify a literal description of the enum value.
# This description is used to generate user interface elements
# from the enumeration. To allow i18n of the description, the
# value is by default put into the N_() macro.

use Text::ParseWords;
use File::Basename;

# gimp-mkenums
# Information about the current enumeration
my $flags;                      # Is enumeration a bitmask?
my $option_lowercase_name;      # A lower case name to use as part of the *_get_type() function, instead of the one that we guess.
                                # For instance, when an enum uses abnormal capitalization and we can not guess where to put the underscores.
my $seenbitshift;               # Have we seen bitshift operators?
my $enum_prefix;                # Prefix for this enumeration
my $enumname;                   # Name for this enumeration
my $enumshort;                  # $enumname without prefix
my $enumnick;                   # lower case version of $enumshort
my $enumindex = 0;              # Global enum counter
my $firstenum = 1;              # Is this the first enumeration per file?
my @entries;                    # [ $name, $val ] for each entry

sub parse_trigraph {
    my $opts = shift;
    my @opts;

    for $opt (quotewords(",", "true", $opts)) {
        $opt =~ s/^\s*//;
        $opt =~ s/\s*$//;
        my ($key,$val) = $opt =~ /(\w+)(?:=(.+))?/;
        defined $val or $val = 1;
        push @opts, $key, $val;
    }
    @opts;
}


sub parse_entries {
    my $file = shift;
    my $file_name = shift;
    my $looking_for_name = 0;

    while (<$file>) {
        # read lines until we have no open comments
        while (m@/\*([^*]|\*(?!/))*$@) {
            my $new;
            defined ($new = <$file>) || die "Unmatched comment in $ARGV";
            $_ .= $new;
        }
        # strip comments w/o options
        s@/\*(?!<)
            ([^*]+|\*(?!/))*
           \*/@@gx;

        # strip newlines
        s@\n@ @;

        # skip empty lines
        next if m@^\s*$@;

        if ($looking_for_name) {
            if (/^\s*(\w+)/) {
                $enumname = $1;
                return 1;
            }
        }

        # Handle include files
        if (/^\#include\s*<([^>]*)>/ ) {
            my $file= "../$1";
            open NEWFILE, $file or die "Cannot open include file $file: $!\n";

            if (parse_entries (\*NEWFILE, $NEWFILE)) {
                return 1;
            } else {
                next;
            }
        }

        if (/^\s*\}\s*(\w+)/) {
            $enumname = $1;
            $enumindex++;
            return 1;
        }

        if (/^\s*\}/) {
            $enumindex++;
            $looking_for_name = 1;
            next;
        }

        if (m@^\s*
              (\w+)\s*                   # name
              (?:=(                      # value
                   \s*\w+\s*\(.*\)\s*       # macro with multiple args
                   |                        # OR
                   (?:[^,/]|/(?!\*))*       # anything but a comma or comment
                  ))?,?\s*
              (?:/\*<                    # options
                (([^*]|\*(?!/))*)
               >\s*\*/)?,?
              \s*$
             @x) {
            my ($name, $value, $options) = ($1,$2,$3);

            if (!defined $flags && defined $value && $value =~ /<</) {
                $seenbitshift = 1;
            }

            if (defined $options) {
                my %options = parse_trigraph($options);
                if (!defined $options{"skip"}) {
                    push @entries, [ $name, $options{nick}, $options{desc}, $options{help}, $options{abbrev} ];
                }
            } else {
                push @entries, [ $name ];
            }

            # skip remaining lines of multiline values
            do {
                if (m/}/) {
                    redo;
                } elsif (m@,\s*(/\*.*?\*/\s*)*$@) {
                    next;
                }
            } while (<$file>);

            # failed to find end of value. bail
            die "$0: $file_name:$.: Unterminated enum, while processing `$name'\n";
        } elsif (m@^\s*\#@) {
            # ignore preprocessor directives
        } else {
            print STDERR "$0: $file_name:$.: Failed to parse `$_'\n";
        }
    }

    return 0;
}

sub version {
    print STDERR "gimp-mkenums based on glib-mkenums version glib-2.0\n";
    print STDERR "gimp-mkenums comes with ABSOLUTELY NO WARRANTY.\n";
    print STDERR "You may redistribute copies of gimp-mkenums under the terms\n";
    print STDERR "of the GNU General Public License which can be found in the\n";
    print STDERR "GIMP source package.";
    exit 0;
}
sub usage {
    print STDERR "Usage: gimp-mkenums [options] [files...]\n";
    print STDERR "  --fhead <text>             output file header\n";
    print STDERR "  --fprod <text>             per input file production\n";
    print STDERR "  --ftail <text>             output file trailer\n";
    print STDERR "  --eprod <text>             per enum text (produced prior to value itarations)\n";
    print STDERR "  --vhead <text>             value header, produced before iterating over enum values\n";
    print STDERR "  --vprod <text>             value text, produced for each enum value\n";
    print STDERR "  --vtail <text>             value tail, produced after iterating over enum values\n";
    print STDERR "  --dhead <text>             description header, produced before iterating over enum value descriptions\n";
    print STDERR "  --dprod <text>             description text, produced for each enum value description\n";
    print STDERR "  --dtail <text>             description tail, produced after iterating over enum value descriptions\n";
    print STDERR "  --comments <text>          comment structure\n";
    print STDERR "  -h, --help                 show this help message\n";
    print STDERR "  -v, --version              print version information\n";
    print STDERR "Production text substitutions:\n";
    print STDERR "  \@EnumName\@                 PrefixTheXEnum\n";
    print STDERR "  \@enum_name\@                prefix_the_xenum\n";
    print STDERR "  \@ENUMNAME\@                 PREFIX_THE_XENUM\n";
    print STDERR "  \@ENUMSHORT\@                THE_XENUM\n";
    print STDERR "  \@enumnick\@                 the_xenum\n";
    print STDERR "  \@VALUENAME\@                PREFIX_THE_XVALUE\n";
    print STDERR "  \@valuenick\@                the-xvalue\n";
    print STDERR "  \@valuedesc\@                descriptions as defined in the header\n";
    print STDERR "  \@valuehelp\@                help texts as defined in the header\n";
    print STDERR "  \@valueabbrev\@              abbreviations as defined in the header\n";
    print STDERR "  \@valueudesc\@               untranslated descriptions as defined in the header\n";
    print STDERR "  \@valueuhelp\@               untranslated help texts as defined in the header\n";
    print STDERR "  \@valueuabbrev\@             untranslated abbreviations as defined in the header\n";
    print STDERR "  \@type\@                     either enum or flags\n";
    print STDERR "  \@Type\@                     either Enum or Flags\n";
    print STDERR "  \@TYPE\@                     either ENUM or FLAGS\n";
    print STDERR "  \@filename\@                 name of current input file\n";
    print STDERR "  \@basename\@                 basename of current input file\n";
    print STDERR "  \@if (...)\@ ... \@endif\@     conditional inclusion\n";
    exit 0;
}

# production variables:
my $fhead = "";   # output file header
my $fprod = "";   # per input file production
my $ftail = "";   # output file trailer
my $eprod = "";   # per enum text (produced prior to value itarations)
my $vhead = "";   # value header, produced before iterating over enum values
my $vprod = "";   # value text, produced for each enum value
my $vtail = "";   # value tail, produced after iterating over enum values
my $dhead = "";   # desc header, produced before iterating over enum values
my $dprod = "";   # desc text, produced for each enum value
my $dtail = "";   # desc tail, produced after iterating over enum values
# other options
my $comment_tmpl = "/* \@comment\@ */";

if (!defined $ARGV[0]) {
    usage;
}
while ($_ = $ARGV[0], /^-/) {
    shift;
    last if /^--$/;
    if    (/^--fhead$/)              { $fhead = $fhead . shift }
    elsif (/^--fprod$/)              { $fprod = $fprod . shift }
    elsif (/^--ftail$/)              { $ftail = $ftail . shift }
    elsif (/^--eprod$/)              { $eprod = $eprod . shift }
    elsif (/^--vhead$/)              { $vhead = $vhead . shift }
    elsif (/^--vprod$/)              { $vprod = $vprod . shift }
    elsif (/^--vtail$/)              { $vtail = $vtail . shift }
    elsif (/^--dhead$/)              { $dhead = $dhead . shift }
    elsif (/^--dprod$/)              { $dprod = $dprod . shift }
    elsif (/^--dtail$/)              { $dtail = $dtail . shift }
    elsif (/^--comments$/)           { $comment_tmpl = shift }
    elsif (/^--help$/ || /^-h$/)     { usage; }
    elsif (/^--version$/ || /^-v$/)  { version; }
    else { usage; }
}

# put auto-generation comment
{
    my $comment = $comment_tmpl;
    $comment =~ s/\@comment\@/Generated data (by gimp-mkenums)/;
    print "\n" . $comment . "\n\n";
}

if (length($fhead)) {
    my $prod = $fhead;

    $prod =~ s/\@filename\@/$ARGV[0]/g;
    $prod =~ s/\@basename\@/basename($ARGV[0])/ge;
    $prod =~ s/\\a/\a/g; $prod =~ s/\\b/\b/g; $prod =~ s/\\t/\t/g; $prod =~ s/\\n/\n/g;
    $prod =~ s/\\f/\f/g; $prod =~ s/\\r/\r/g;

    print "$prod\n";
}

while (<>) {
    if (eof) {
        close (ARGV);           # reset line numbering
        $firstenum = 1;         # Flag to print filename at next enum
    }

    # read lines until we have no open comments
    while (m@/\*([^*]|\*(?!/))*$@) {
        my $new;
        defined ($new = <>) || die "Unmatched comment in $ARGV";
        $_ .= $new;
    }
    # strip comments w/o options
    s@/\*(?!<)
       ([^*]+|\*(?!/))*
       \*/@@gx;

    # ignore forward declarations
    next if /^\s*typedef\s+enum.*;/;

    if (m@^\s*typedef\s+enum\s*
           (\{)?\s*
           (?:/\*<
             (([^*]|\*(?!/))*)
            >\s*\*/)?
         @x) {
        if (defined $2) {
            my %options = parse_trigraph ($2);
            next if defined $options{"skip"};
            $enum_prefix = $options{prefix};
            $flags = $options{flags};
            $option_lowercase_name = $options{lowercase_name};
        } else {
            $enum_prefix = undef;
            $flags = undef;
            $option_lowercase_name = undef;
        }
        # Didn't have trailing '{' look on next lines
        if (!defined $1) {
            while (<>) {
                if (eof) {
                    die "Hit end of file while parsing enum in $ARGV";
                }
                if (s/^\s*\{//) {
                    last;
                }
            }
        }

        $seenbitshift = 0;

        @entries = ();

        # Now parse the entries
        parse_entries (\*ARGV, $ARGV);

        # figure out if this was a flags or enums enumeration
        if (!defined $flags) {
            $flags = $seenbitshift;
        }

        # Autogenerate a prefix
        if (!defined $enum_prefix) {
            for (@entries) {
                my $nick = $_->[1];
                if (!defined $nick) {
                    my $name = $_->[0];
                    if (defined $enum_prefix) {
                        my $tmp = ~ ($name ^ $enum_prefix);
                        ($tmp) = $tmp =~ /(^\xff*)/;
                        $enum_prefix = $enum_prefix & $tmp;
                    } else {
                        $enum_prefix = $name;
                    }
                }
            }
            if (!defined $enum_prefix) {
                $enum_prefix = "";
            } else {
                # Trim so that it ends in an underscore
                $enum_prefix =~ s/_[^_]*$/_/;
            }
        } else {
            # canonicalize user defined prefixes
            $enum_prefix = uc($enum_prefix);
            $enum_prefix =~ s/-/_/g;
            $enum_prefix =~ s/(.*)([^_])$/$1$2_/;
        }


        # enumname is e.g. GMatchType
        $enspace = $enumname;
        $enspace =~ s/^([A-Z][a-z]*).*$/$1/;

        $enumshort = $enumname;
        $enumshort =~ s/^[A-Z][a-z]*//;
        $enumshort =~ s/([^A-Z])([A-Z])/$1_$2/g;
        $enumshort =~ s/([A-Z][A-Z])([A-Z][0-9a-z])/$1_$2/g;
        $enumshort = uc($enumshort);

        $enumlong = uc($enspace) . "_" . $enumshort;
        $enumsym = lc($enspace) . "_" . lc($enumshort);

        $enumnick = lc($enumshort);
        $enumnick =~ tr/_/-/;

        for $entry (@entries) {
            my ($name,$nick,$desc,$help,$abbrev) = @{$entry};
            if (!defined $nick) {
                ($nick = $name) =~ s/^$enum_prefix//;
                $nick =~ tr/_/-/;
                $nick = lc($nick);
            }
            if (!defined $desc) {
                $udesc = "\"$name\"";
            } else {
                $udesc = $desc;
            }
            if (!defined $desc) {
                $desc = "\"$name\"";
            } else {
                $desc = "NC_(\"$enumnick\", $desc)";
            }
            if (!defined $help) {
                $uhelp = "NULL";
            } else {
                $uhelp = $help;
            }
            if (!defined $help) {
                $help = "NULL";
            } else {
                $help = "N_($help)";
            }
            if (!defined $abbrev) {
                $uabbrev = "NULL";
            } else {
                $uabbrev = $abbrev;
            }
            if (!defined $abbrev) {
                $abbrev = "NULL";
            } else {
                $abbrev = "NC_(\"$enumnick\", $abbrev)";
            }
            @{$entry} = ($name, $nick, $desc, $help, $abbrev, $udesc, $uhelp, $uabbrev);
        }


        # Spit out the output

        # The options might override the lower case name if it could
        # not be generated correctly:
        if (defined($option_lowercase_name)) {
            $enumsym = $option_lowercase_name;
        }

        if ($firstenum) {
            $firstenum = 0;

            if (length($fprod)) {
                my $prod = $fprod;

                $prod =~ s/\@filename\@/$ARGV/g;
                $prod =~ s/\@basename\@/basename($ARGV)/ge;
                $prod =~ s/\\a/\a/g; $prod =~ s/\\b/\b/g; $prod =~ s/\\t/\t/g; $prod =~ s/\\n/\n/g;
                $prod =~ s/\\f/\f/g; $prod =~ s/\\r/\r/g;

                print "$prod\n";
            }
        }

        if (length($eprod)) {
            my $prod = $eprod;

            $prod =~ s/\@enum_name\@/$enumsym/g;
            $prod =~ s/\@EnumName\@/$enumname/g;
            $prod =~ s/\@ENUMSHORT\@/$enumshort/g;
            $prod =~ s/\@enumnick\@/$enumnick/g;
            $prod =~ s/\@ENUMNAME\@/$enumlong/g;
            if ($flags) { $prod =~ s/\@type\@/flags/g; } else { $prod =~ s/\@type\@/enum/g; }
            if ($flags) { $prod =~ s/\@Type\@/Flags/g; } else { $prod =~ s/\@Type\@/Enum/g; }
            if ($flags) { $prod =~ s/\@TYPE\@/FLAGS/g; } else { $prod =~ s/\@TYPE\@/ENUM/g; }
            $prod =~ s/\@if (\((?>[^()]|(?1))*\))\@(.*?)\@endif\@/eval ($1) ? "$2" : ""/ges;
            $prod =~ s/\\a/\a/g; $prod =~ s/\\b/\b/g; $prod =~ s/\\t/\t/g; $prod =~ s/\\n/\n/g;
            $prod =~ s/\\f/\f/g; $prod =~ s/\\r/\r/g;

            print "$prod\n";
        }

        if (length($vhead)) {
            my $prod = $vhead;

            $prod =~ s/\@enum_name\@/$enumsym/g;
            $prod =~ s/\@EnumName\@/$enumname/g;
            $prod =~ s/\@ENUMSHORT\@/$enumshort/g;
            $prod =~ s/\@enumnick\@/$enumnick/g;
            $prod =~ s/\@ENUMNAME\@/$enumlong/g;
            if ($flags) { $prod =~ s/\@type\@/flags/g; } else { $prod =~ s/\@type\@/enum/g; }
            if ($flags) { $prod =~ s/\@Type\@/Flags/g; } else { $prod =~ s/\@Type\@/Enum/g; }
            if ($flags) { $prod =~ s/\@TYPE\@/FLAGS/g; } else { $prod =~ s/\@TYPE\@/ENUM/g; }
            $prod =~ s/\@if (\((?>[^()]|(?1))*\))\@(.*?)\@endif\@/eval ($1) ? "$2" : ""/ges;
            $prod =~ s/\\a/\a/g; $prod =~ s/\\b/\b/g; $prod =~ s/\\t/\t/g; $prod =~ s/\\n/\n/g;
            $prod =~ s/\\f/\f/g; $prod =~ s/\\r/\r/g;

            print "$prod\n";
        }

        if (length($vprod)) {
            my $prod = $vprod;

            $prod =~ s/\\a/\a/g; $prod =~ s/\\b/\b/g; $prod =~ s/\\t/\t/g; $prod =~ s/\\n/\n/g;
            $prod =~ s/\\f/\f/g; $prod =~ s/\\r/\r/g;
            for (@entries) {
                my ($name,$nick,$desc,$help,$abbrev,$udesc,$uhelp,$uabbrev) = @{$_};
                my $tmp_prod = $prod;

                $tmp_prod =~ s/\@VALUENAME\@/$name/g;
                $tmp_prod =~ s/\@valuenick\@/$nick/g;
                $tmp_prod =~ s/\@valuedesc\@/$desc/g;
                $tmp_prod =~ s/\@valuehelp\@/$help/g;
                $tmp_prod =~ s/\@valueabbrev\@/$abbrev/g;
                $tmp_prod =~ s/\@valueudesc\@/$udesc/g;
                $tmp_prod =~ s/\@valueuhelp\@/$uhelp/g;
                $tmp_prod =~ s/\@valueuabbrev\@/$uabbrev/g;
                if ($flags) { $tmp_prod =~ s/\@type\@/flags/g; } else { $tmp_prod =~ s/\@type\@/enum/g; }
                if ($flags) { $tmp_prod =~ s/\@Type\@/Flags/g; } else { $tmp_prod =~ s/\@Type\@/Enum/g; }
                if ($flags) { $tmp_prod =~ s/\@TYPE\@/FLAGS/g; } else { $tmp_prod =~ s/\@TYPE\@/ENUM/g; }
                $tmp_prod =~ s/\@if (\((?>[^()]|(?1))*\))\@(.*?)\@endif\@/eval ($1) ? "$2" : ""/ges;

                print "$tmp_prod\n";
            }
        }

        if (length($vtail)) {
            my $prod = $vtail;

            $prod =~ s/\@enum_name\@/$enumsym/g;
            $prod =~ s/\@EnumName\@/$enumname/g;
            $prod =~ s/\@ENUMSHORT\@/$enumshort/g;
            $prod =~ s/\@enumnick\@/$enumnick/g;
            $prod =~ s/\@ENUMNAME\@/$enumlong/g;
            if ($flags) { $prod =~ s/\@type\@/flags/g; } else { $prod =~ s/\@type\@/enum/g; }
            if ($flags) { $prod =~ s/\@Type\@/Flags/g; } else { $prod =~ s/\@Type\@/Enum/g; }
            if ($flags) { $prod =~ s/\@TYPE\@/FLAGS/g; } else { $prod =~ s/\@TYPE\@/ENUM/g; }
            $prod =~ s/\@if (\((?>[^()]|(?1))*\))\@(.*?)\@endif\@/eval ($1) ? "$2" : ""/ges;
            $prod =~ s/\\a/\a/g; $prod =~ s/\\b/\b/g; $prod =~ s/\\t/\t/g; $prod =~ s/\\n/\n/g;
            $prod =~ s/\\f/\f/g; $prod =~ s/\\r/\r/g;

            print "$prod\n";
        }

        if (length($dhead)) {
            my $prod = $dhead;

            $prod =~ s/\@enum_name\@/$enumsym/g;
            $prod =~ s/\@EnumName\@/$enumname/g;
            $prod =~ s/\@ENUMSHORT\@/$enumshort/g;
            $prod =~ s/\@enumnick\@/$enumnick/g;
            $prod =~ s/\@ENUMNAME\@/$enumlong/g;
            if ($flags) { $prod =~ s/\@type\@/flags/g; } else { $prod =~ s/\@type\@/enum/g; }
            if ($flags) { $prod =~ s/\@Type\@/Flags/g; } else { $prod =~ s/\@Type\@/Enum/g; }
            if ($flags) { $prod =~ s/\@TYPE\@/FLAGS/g; } else { $prod =~ s/\@TYPE\@/ENUM/g; }
            $prod =~ s/\@if (\((?>[^()]|(?1))*\))\@(.*?)\@endif\@/eval ($1) ? "$2" : ""/ges;
            $prod =~ s/\\a/\a/g; $prod =~ s/\\b/\b/g; $prod =~ s/\\t/\t/g; $prod =~ s/\\n/\n/g;
            $prod =~ s/\\f/\f/g; $prod =~ s/\\r/\r/g;

            print "$prod\n";
        }

        if (length($dprod)) {
            my $prod = $dprod;

            $prod =~ s/\\a/\a/g; $prod =~ s/\\b/\b/g; $prod =~ s/\\t/\t/g; $prod =~ s/\\n/\n/g;
            $prod =~ s/\\f/\f/g; $prod =~ s/\\r/\r/g;
            for (@entries) {
                my ($name,$nick,$desc,$help,$abbrev,$udesc,$uhelp,$uabbrev) = @{$_};
                my $tmp_prod = $prod;

                $tmp_prod =~ s/\@VALUENAME\@/$name/g;
                $tmp_prod =~ s/\@valuenick\@/$nick/g;
                $tmp_prod =~ s/\@valuedesc\@/$desc/g;
                $tmp_prod =~ s/\@valuehelp\@/$help/g;
                $tmp_prod =~ s/\@valueabbrev\@/$abbrev/g;
                $tmp_prod =~ s/\@valueudesc\@/$udesc/g;
                $tmp_prod =~ s/\@valueuhelp\@/$uhelp/g;
                $tmp_prod =~ s/\@valueuabbrev\@/$uabbrev/g;
                if ($flags) { $tmp_prod =~ s/\@type\@/flags/g; } else { $tmp_prod =~ s/\@type\@/enum/g; }
                if ($flags) { $tmp_prod =~ s/\@Type\@/Flags/g; } else { $tmp_prod =~ s/\@Type\@/Enum/g; }
                if ($flags) { $tmp_prod =~ s/\@TYPE\@/FLAGS/g; } else { $tmp_prod =~ s/\@TYPE\@/ENUM/g; }
                $tmp_prod =~ s/\@if (\((?>[^()]|(?1))*\))\@(.*?)\@endif\@/eval ($1) ? "$2" : ""/ges;

                print "$tmp_prod\n";
            }
        }

        if (length($dtail)) {
            my $prod = $dtail;

            $prod =~ s/\@enum_name\@/$enumsym/g;
            $prod =~ s/\@EnumName\@/$enumname/g;
            $prod =~ s/\@ENUMSHORT\@/$enumshort/g;
            $prod =~ s/\@enumnick\@/$enumnick/g;
            $prod =~ s/\@ENUMNAME\@/$enumlong/g;
            if ($flags) { $prod =~ s/\@type\@/flags/g; } else { $prod =~ s/\@type\@/enum/g; }
            if ($flags) { $prod =~ s/\@Type\@/Flags/g; } else { $prod =~ s/\@Type\@/Enum/g; }
            if ($flags) { $prod =~ s/\@TYPE\@/FLAGS/g; } else { $prod =~ s/\@TYPE\@/ENUM/g; }
            $prod =~ s/\@if (\((?>[^()]|(?1))*\))\@(.*?)\@endif\@/eval ($1) ? "$2" : ""/ges;
            $prod =~ s/\\a/\a/g; $prod =~ s/\\b/\b/g; $prod =~ s/\\t/\t/g; $prod =~ s/\\n/\n/g;
            $prod =~ s/\\f/\f/g; $prod =~ s/\\r/\r/g;

            print "$prod\n";
        }
    }
}

if (length($ftail)) {
    my $prod = $ftail;

    $prod =~ s/\@filename\@/$ARGV/g;
    $prod =~ s/\@basename\@/basename($ARGV)/ge;
    $prod =~ s/\@if (\((?>[^()]|(?1))*\))\@(.*?)\@endif\@/eval ($1) ? "$2" : ""/ges;
    $prod =~ s/\\a/\a/g; $prod =~ s/\\b/\b/g; $prod =~ s/\\t/\t/g; $prod =~ s/\\n/\n/g;
    $prod =~ s/\\f/\f/g; $prod =~ s/\\r/\r/g;

    print "$prod\n";
}

# put auto-generation comment
{
    my $comment = $comment_tmpl;
    $comment =~ s/\@comment\@/Generated data ends here/;
    $comment =~ s/\@if (\((?>[^()]|(?1))*\))\@(.*?)\@endif\@/eval ($1) ? "$2" : ""/ges;
    print "\n" . $comment . "\n\n";
}