Unrelated, but I find it interesting that Ruby's string representations of these differ (in 2.0.0, at least). One is printed using a unicode escape, the other as a hex escape:

``` irb
irb(main):024:0> ?\C-?
=> "\u007F"
irb(main):025:0> 127.chr
=> "\x7F"
irb(main):026:0> ?\C-? == 127.chr
=> true
```
Cute.