[Python-3000] Fwd: Re: Fwd: Re: Fwd: Re: Octal (original) (raw)

Georg Brandl g.brandl at gmx.net
Sat Mar 17 09:57:43 CET 2007

Patrick Maupin schrieb:

On 3/16/07, Guido van Rossum <guido at python.org> wrote:

Cool. Then I'll support your support for 0o, and only using lowercase 0b, 0o, 0x. Maybe that'll settle the discussion about this bikeshed's color. I'm also in favor of only using lowercase j for complex and lowercase r for raw strings. (u will disappear with the Unicode/str unification.) In general, I support this, and weary of discussing and documenting the exact shade of battleship grey we have decided upon. However, I need to ask about one blue racing stripe along the left-hand side :) Hexadecimal numbers traditionally support upper- and lower-case display, chosen by the case of the 'x' character. Python supports this both for input and display, and probably needs to continue to support the option of upper or lowercase hex for display. I think perhaps it should be supported for input, as well, both to have symmetry with the display, and to allow for easy cut and paste (and eval() and int(s, 0)) of hexadecimal numbers from other sources. Obviously, we cannot support this easy eval() or int(s, 0) for octal in the future, but arguably, there are a lot more hexadecimal numbers of either case "in the wild" than there are octal numbers. I understand that the proposal is to allow 0xabc or 0xABC, but not allow 0Xabc or 0XABC, but one of the strengths of Python is that I can easily parse files containing numerical data from almost arbitrary sources, and this may be a case where "practicality beats purity" should rule, although it may also be an easy counterargument that I/O symmetry is not really that important, and that one can easily write "x = x.replace('0X', '0x')" for the example I have given. Your call.

Please no gratuitous breakage!

I'd continue to allow 0Xabc and 0xABC and 0xabc and 0XABC. Do a Google codesearch, and you'll find them in Python code as well as data files. I'd not allow 0O or 0B prefixes. I'd not allow an "R" string prefix -- I've never seen anyone use it.

Georg

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