[Python-Dev] PEP 460 reboot (original) (raw)

MRAB python at mrabarnett.plus.com
Tue Jan 14 03:55:06 CET 2014

On 2014-01-14 02:25, Terry Reedy wrote:

On 1/13/2014 4:32 PM, Guido van Rossum wrote:

> I will doggedly keep posting to this thread rather than creating more threads. Please permit to to doggedly keep pointing you toward the possible solution I posted on the tracker last October.

But formatb() feels absurd to me. PEP 460 has neither a precise specification or any actual examples, so I can't tell whether the Two days ago, I reposted byteformat() here on pydev with a precise text specification added to the code, and with an expanded test example. I have just added another example based on your question below. intention is that the format string can only contain {...} sequences or whether it can also contain "regular" characters. Translating to formatb(), my question comes down to the legality of the following example:

b'Hello, {}'.formatb(name) # Where name is some bytes object If this is allowed, it reintroduces the ASCII bias (since the substring 'Hello' is clearly ASCII). Since byteformat() uses re to find {} replacement fields, it only has such ascii bias as re has, which I believe is not much, if any. As far as re and byteformat are concerned, everything outside of the {...} fields is uninterpreted bytes. As far as bytes.join is concerned, both joiner and joined are uninterpreted bytes. >>> byteformat(b'\x00{}\x02{}def', (b'\x01', b'abc',)) b'\x00\x01\x02abcdef' [snip] Couldn't that suffer from false positives, i.e. binary data that happens to match? (Rare, yes, but possible.)

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