You're asking, "how can I generally turn escape sequences into what they correspond to", right?

### updated (thanks, Abigail)
### Unicode NOT included

sub expand_escapes {
  local $_ = shift;
  s{
    (
      \\
      (?:
        x[A-Fa-f0-9]{0,2}  # hex escape
        |
        0[0-7]{0,3}        # octal escape
        |
        c.                 # ctrl-escape
        |
        .                  # any other
      )
    )
  }{qq["$1"]}geexs;
  return $_;
}
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japhy -- Perl and Regex Hacker