MRAB writes: > RFC 4648 says """Base encoding of data is used in many situations to > store or transfer data in environments that, perhaps for legacy reasons, > are restricted to US-ASCII [1] data.""". > > To me, "US-ASCII" is an encoding, so it appears to be talking about > encoding binary data (bytestrings) to ASCII-encoded text (bytestrings).
I think that's a misreading, inconsistent with the rest of the RFC. The references to US-ASCII are not clearly normative, as the value- character mappings are given in tables, and are self-contained. (The one you quote is clearly informative, since it describes a use-case.) The term "subset of US-ASCII" suggests repertoire, not encoding, as does the use of "alphabet" to refer to these subsets. *Every* (other?) normative statement is very careful to say that input of a Base-n encoder is "octets" (with two uses of "bytes" in the definition of Base32), and the output is "characters". There are no exceptions, and there are *no* references to encoding of characters or the corresponding character codes (except the possible implicit reference via "US-ASCII"). I can make no sense of those facts if the intent of the RFC is to restrict the output of a Base-n encoder to characters encoded in (8-bit) US-ASCII. Why not just say so, and use "octets" and their ASCII codes throughout, with the corresponding characters used as informative commentary? I think it much more likely that "subset of the character repertoire of US-ASCII" was intended, but abbreviated to "subset of US-ASCII". This kind of abbreviation is very common in informal discussion of coded character sets. I admit it's a little surprising that the author would be so incautious in his use of "US-ASCII", but if he really meant US-ASCII- the-encoding, I find the style of the rest of the RFC astonishing! _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
