c:\@Work\Perl>perl -wMstrict -le
"print qq{Perl version $] };
 ;;
 BEGIN {
   my %xlate_map = qw/ ( l_paren  ) r_paren  { l_curly  } r_curly /;
   my $xlate_targets = join '', map quotemeta, keys %xlate_map;
   ;;
   sub xlate {
     my ($s) = @_;
     ;;
     (my $t = $s) =~ s{ ([$xlate_targets]) }{$xlate_map{$1}}xmsog;
     return $t;
     }
   }
 ;;
    my $str = 'a { b } c ( d ) e {{F}} ((G))';
    my $xlt = xlate($str);
    print qq{'$xlt'};
"
Perl version 5.008009
'a l_curly b r_curly c l_paren d r_paren e l_curlyl_curlyFr_curlyr_curly l_parenl_parenGr_parenr_paren'