my $np;
$np=	qr{
		\{   
		(?:
			(?> [^ \{\} ]+)
			|
			(??{$np})
		)*
		\}
	}x;

my $text = "
functio
{
  1
    {2*3}
}";

my $funcpat = qr/(\w+)($np)/ms;

if ($text =~/^$funcpat/ms){
	print "\n\nmatches\n";
	print "$1\n";
	print "$2\n";
	print $text;