Not sure if this is helpful or not but for rot13, there is Crypt::Rot13 on CPAN. Just a reminder to check CPAN for everything first....

Now my code would be simpler:

    my $x = ...
    my %hash = map { s/(^'|'$)// } split /(:|, )/ $x;
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That assumes you want something like

  %x = ( a => 'n', b => 'o', ...);
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But it also looks trivial to convert this to valid json and use that module

Update: On second thought that above approach won't work. I think you will need to do something like:

    my $x = ...
    my %hash = map { my $v = $_; $v =~ s/(^'|'$)//; $v} split /(:|, )/
+ $x;
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