Add s///r (non-destructive substitution).
This changes s/// so that it doesn't act destructively on its target.
Instead it returns the result of the substitution (or the original string if
there was no match).
In addition this patch:
* Adds a new warning when s///r happens in void context.
* Adds a error when you try to use s///r with !~
* Makes it so constant strings can be bound to s///r with =~
* Adds documentation.
* Adds some tests.
* Updates various debug code so it knows about the /r flag.
* Adds some new 'r' words to B::Deparse.
14 files changed: