I had an objection to using spaces in numeric literals last time around and it still stands, and it still stands in the new one.
What happens if you use a literal like 0x10f 304? Is 304 treated as decimal or hexadecimal? It's not clear how you would begin to combine it The way string concatenation works, it takes two independent string literals, and combines them. If you specify r'\n' 'abc\n', the first half is treated independently as a raw string, and the second half is treated as a normal string. The result is '\\nabc\n'. With numeric literals, this behavior doesn't even make sense. How do you concatenate hex 10f with decimal 304? I suppose you could multiply 0x10f by 1000, and add them, but this probably wouldn't fit any practical usecase. Alternatively, you could raise an exception, and require the user to use numeric literals of the same type, like 0x10f 0x304, but then you lose any readability benefit you might have gained by dropping the _ to begin with. If, on the other hand, you want to combine the tokens before processing their independent meanings, which makes the most intuitive sense, well, in that case we're no longer talking about an operation analogous to string contcatenation. We're talking about integers no longer being simple tokens that can be assigned a value. I'm not familiar with the code that makes all this happen in C Python (or any other implementation for that matter), but it seems like it extends the complexity of the parser unnecessarily. I'm concerned that the benefit in readability will be outweighed by the burden it places on the parser, and the cognitive burden on the programmer of knowing what to expect when using non-decimal numeric literals. For that reason, I'm a -1 on using a space in numeric literals, but +1 on using some other separator, and an _, in spite of its slight awkwardness in typing, seems like a good idea. If someone with a solid understanding of the python parser could chime in that this wouldn't cause as much friction as I think, and explain a clean, elegant implementation for this, many of my concerns would be alleviated, and I would change my -1 to a -0. Cheers, Cliff On Mon, 2009-08-24 at 00:01 +1000, Ben Finney wrote: > garabik-news-2005...@kassiopeia.juls.savba.sk writes: > > Why not just use the space? 123 000 looks better than 123_000, and is > > not syntactically ambiguous (at least in python). And as it already > > works for string literals, it could be applied to numbers, too… > > +1 to all this. I think this discussion was had many months ago, but > can't recall how it ended back then. > > -- > \ “Only the educated are free.” —Epictetus, _Discourses_ | > `\ | > _o__) | > Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
