#!/usr/bin/perl -w
use strict;
use Regexp::Common;

my $text = <<TEXT;
   onValidate
   {
    stuff in here
    {
       other stuff
    }
   }
   keep this
   {
       remove this {and {this}}
   }
TEXT

$text =~ s/$RE{balanced}{-parens=>'{}'}//g;

print $text;

##</code><code>##

our $re = qr/(?:\{(?:(?>[^\{\}]+)|(??{$re}))*\})/;

##</code><code>##

use YAPE::Regex::Explain;
print YAPE::Regex::Explain->new($re)->explain;

##</code><code>##

The regular expression:

(?-imsx:(?:\{(?:(?>[^\{\}]+)|(??{$re}))*\}))

matches as follows:

NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  (?:                      group, but do not capture:
----------------------------------------------------------------------
    \{                       '{'
----------------------------------------------------------------------
    (?:                      group, but do not capture (0 or more
                             times (matching the most amount
                             possible)):
----------------------------------------------------------------------
      (?>                      match (and do not backtrack
                               afterwards):
----------------------------------------------------------------------
        [^\{\}]+                 any character except: '\{', '\}' (1
                                 or more times (matching the most
                                 amount possible))
----------------------------------------------------------------------
      )                        end of look-ahead
----------------------------------------------------------------------
     |                        OR
----------------------------------------------------------------------
      (??{$re})                run this block of Perl code (that
                               isn't interpolated until RIGHT NOW)
----------------------------------------------------------------------
    )*                       end of grouping
----------------------------------------------------------------------
    \}                       '}'
----------------------------------------------------------------------
  )                        end of grouping
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------