[Python-Dev] Proposal: .pyc file format change

[Greg Stein]

I don't think we should have a two-byte magic value. Especially where
those two bytes are printable, 7-bit ASCII.

"But it is four bytes," you say. Nope. It is two plus a couple parameters
that can now change over time.

To ensure uniqueness, I think a four-byte magic should stay.

I would recommend the approach of adding opcodes into the marshal format.
Specifically, 'V' followed by a single byte. That can only occur at the
beginning. If it is not present, then you know that you have an old
marshal value.

Cheers,
-g

On Sun, 28 May 2000, Christian Tismer wrote:
> Peter Funk wrote:
> > 
> > [...]
> > > For simplicity, comapibility and ease of change,
> > > I vote with +1 for adopting the solution of
> > >
> > > byte 0: 'P'
> > > byte 1: 'Y'
> > > byte 2: version number (counting from 1)
> > > byte 3: option byte (8 bits: one for each option;
> > >                      bit 0: -U cmd switch)
> > >
> > > If that turns out to be insufficient in some future,
> > > do a complete redesign.
> > 
> > What about the CR/LF issue with some Mac Compilers (see
> > Guido's mail for details)?  Can we simply drop this?
> 
> Well, forgot about that.
> How about swapping bytes 0 and 1?
> 
> -- 
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-- 
Greg Stein, http://www.lyra.org/