[Guido]
So using an opcode for framing is out? (Sorry, I've lost track of the back-and-forth.)
It was never in ;-) I'd *prefer* one, but not enough to try to block the PEP. As is, framing is done at a "lower level" than opcode decoding. I fear this is brittle, for all the usual "explicit is better than implicit" kinds of reasons. The only way now to know that you're looking at a frame size is to keep a running count of bytes processed and realize you've reached a byte offset where a frame size "is expected". With an opcode, framing could also be optional (whenever desired), because frame sizes would be _explicitly_ marked in the byte stream Then the framing overhead for small pickles could drop to 0 bytes (instead of the current 8, or 1 thru 9 under various other schemes). Ideal would be an explicit framing opcode combined with variable-length size encoding. That would never require more bytes than the current scheme, and 'almost always" require fewer. But even I don't think it's of much value to chop a few bytes off every 64KB of pickle ;-)