🚀 go-pugleaf

In article <3125C1DC.35AE@ix.netcom.com>
           pderocco@ix.netcom.com "Paul D. DeRocco" writes:

> Why, oh why, aren't we allowed to write binary numbers in C++? The 
> standard could trivially be extended by allowing binary numbers to be 
> written, prefixed with 0b, or perhaps 0y. This makes bit masks _much_ 
> easier to read. And it wouldn't break any presently legal program.

You might like to try the following:

	template<int digit> struct bit;

	struct bit<0> { enum { value = 0 }; };

	struct bit<1> { enum { value = 1 }; };

	template<int digits> struct bin;

	struct bin<0> { enum { value = 0 }; };

	template<int digits> struct bin
	{
		enum
		{
			value =	bin<digits / 10>::value * 2 +
				bit<digits % 10>::value
		};
	};

Used as

	bin<1101>::value
	bin<11001100>::value

Catches as illegal

	bin<12345>::value
	bin<011001>::value

If nothing else, the code is a good source of amusement -- present it to your
colleagues w/ the names changed to perplex the innocent :-)

Seriously, this is practical w/i the constraints of 32 bit ints and <= 10 bit
bit specs, and for compilers using the old specialization syntax (ie. the
majority).

> Another related improvement would be to allow embedded underscores in 
> numbers, for clarity. 1_000_000_000 is obviously a billion, while 
> 1000000000 is not so obviously a billion. Same for 0x8000_0000, or 
> 0y0001_1110_0000_0000. Again, it doesn't break anything.

Alternatively we could try for space separation and handle adjacent literals
as one, as is done w/ string literals:

	1 000 000 000
	0x 8000 0000
	0.12345 67890

:->
_______________________________________________________________________

  Kevlin A P Henney        2sdg Ltd        kevlin@two-sdg.demon.co.uk
  "What happens to the hole when the cheese is gone?"  Bertolt Brecht
_______________________________________________________________________
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