use strict; 
use warnings; 
use 5.012;

use Parse::RecDescent;

$::RD_ERRORS = 1; #Parser dies when it encounters an error
$::RD_WARN   = 1; #Enable warnings - warn on unused rules &c.
$::RD_HINT   = 1; #Give out hints to help fix problems.
#$::RD_TRACE  = 1; #Trace parsers' behaviour

my $text = <<'END_OF_TEXT';
{ hello }
END_OF_TEXT

my $grammar = <<'END_OF_GRAMMAR';
    {
        use 5.012;
        use Data::Dumper;
    }

    startrule:  brace_block(s)

    brace_block:    <rulevar: ($lbraces, $rbraces)>

    brace_block:    lbrace(1..) 
                    { 
                        $lbraces = join '', @{$item[1]};  
                        $rbraces = '}' x length $lbraces;  
                    }
                    'hello'
                    "$rbraces"
                    {
                        say Dumper(\@item);
                        #$return = "$lbraces $item[2] $rbraces";
                    }

               

    lbrace: / [{] /xms

--output:--
$VAR1 = [
          'brace_block',
          [
            '{'
          ],
          '}',
          'hello',
          '}'
        ];

...
...
...