CAR(agg)=(
	ID(str)='12345'
	TITLE(agg)=(
		TITLE(text 5)='Prius'
	)
	RATING(text 4)='Good'
	CAT(agg)=(
		LABEL(text 6)='Hybrid'
		REL(int)=8
	)
	CAT(agg)=(
		LABEL(text 6)='Family'
		REL(int)=10
	)
)

CAR(agg)=(
	ID(str)='22222'
	TITLE(agg)=(
		TITLE(text 7)='Voyager'
	)
	RATING(text 3)='Bad'
	CAT(agg)=(
		LABEL(text 6)='Family'
		REL(int)=10
	)
	CAT(agg)=(
		LABEL(text 3)='Van'
		REL(int)=9
	)
)

##</code><code>##

#!/usr/bin/perl

use Parse::RecDescent;

$grammar = q{

    startrule: root(s)

    root: object {
        print "root\n";
    }

    object: name "(agg)=(" body(s?) closeobject {
        print "object <$item{name}>\n"; 
    }

    name: /\w+/
    
    body: /\s+/
        | object
        | property { print "property $item{property}\n";   }

    property: name /\(\w+\s*\d*\)=/ value {
        "<$item{name}>$item{value}</$item{name}>" }

    value: value1 | value2
    
    value1: /\w+/
    
    value2: /'.+'/ { substr $item[1], 1, (length $item[1]) - 2 }

    closeobject: ")" {
        print "close\n";
    }
};

$parser = Parse::RecDescent->new($grammar);

undef $/;
$text = <>;

print "<ROOT>\n";
$parser->startrule($text);
print "</ROOT>\n";

##</code><code>##

<ROOT>
    <CAR>
        <ID>12345</ID>
        <TITLE>Prius</TITLE>
        <RATING>Good</RATING>
        <CAT>
            <LABEL>Hybrid</LABEL>
            <REL>8</REL>
        </CAT>
        <CAT>
            <LABEL>Family</LABEL>
            <REL>10</REL>
        </CAT>
    </CAR>
    <CAR>
        <ID>22222</ID>
        <TITLE>Voyager</TITLE>
        <RATING>Bad</RATING>
        <CAT>
            <LABEL>Family</LABEL>
            <REL>10</REL>
        </CAT>
        <CAT>
            <LABEL>Van</LABEL>
            <REL>9</REL>
        </CAT>
    </CAR>
</ROOT>