use Parse::RecDescent;
use Data::Dumper;

my $grammar = q{
  startrule: logical_expr

  logical_expr: comparison_expr logical_op logical_expr { [@item[1,2,3]] }
              | comparison_expr
  logical_op: /\\|\\||or|&&|and/

  comparison_expr: paren_expr comparison_op comparison_expr { [@item[1,2,3]] }
                 | paren_expr
  comparison_op: />=?|<=?|!=|==|le|ge|eq|ne|lt|gt/

  paren_expr: '(' logical_expr ')' { $item[2] }
            | atom

  atom: /[A-Za-z_][A-Za-z0-9_]*/
};


my $parser = new Parse::RecDescent $grammar;

for (<DATA>) {
  print $_;
  print Dumper $parser->startrule($_);
  print "============\n";
}

__DATA__
foo == bar || baz < bar
foo == bar || baz < bar || foo && bar
(foo || bar) || baz