s/\\n/\n/g;

##</code><code>##

s/\\/\\s/g;
s/\n/\\n/g;
s/\r/\\r/g;

##</code><code>##

s/\\n/\n/g;
s/\\r/\r/g;
s/\\s/\\/g;

##</code><code>##

my %xlat = ('\\' => "\\", 'n' => "\n", 'r' => "\r");

s/\G(?:\\(.)|(.))/defined($1) ? $xlat{$1} : $2/eg;