Backwards emulation rather than backwards compatibility?

[Antaeus Feldspar]

I've seen both sides of the compatibility debate.  "You're breaking my 
scripts!" vs. "You're holding back the language!" and I can understand 
both sides.  While I do not think there is a perfect solution, I was 
struck the other day by a possible way to bridge the gap.

Could the python interpreter be equipped with a mode that would allow it 
to emulate past interpreters?  Thus, if someone needed access to a 
script that was designed for 1.5.2, they could pass a "--1.5.2" argument 
to the interpreter and have it run under 1.5.2's rules; more to the 
point, if a script's author wanted to be sure that their script could 
run on anything from 1.5.2 to 2.3, they could do it all with a single 
interpreter, rather than have to have a separate interpreter for 
checking each compatibility.

	-jc