MRAB wrote:
James Harris wrote:
On 23 Aug, 00:16, Mel <mwil...@the-wire.com> wrote:
James Harris wrote:
I have no idea why Ada which uses the # also apparently uses it to end
a number
2#1011#, 8#7621#, 16#c26b#
Interesting. They do it because of this example from
<http://archive.adaic.com/standards/83rat/html/ratl-02-01.html#2.1>:
Thanks for providing an explanation.
2#1#E8 -- an integer literal of value 256
where the E prefixes a power-of-2 exponent, and can't be taken as a
digit of
the radix. That is to say
16#1#E2
would also equal 256, since it's 1*16**2 .
Here's another suggested number literal format. First, keep the
familar 0x and 0b of C and others and to add 0t for octal. (T is the
third letter of octal as X is the third letter of hex.) The numbers
above would be
0b1011, 0t7621, 0xc26b
Second, allow an arbitrary number base by putting base and number in
quotes after a zero as in
0"2:1011", 0"8:7621", 0"16:c26b"
Why not just put the base first, followed by the value in quotes:
2"1011", 8"7621", 16"c26b"
It's always a bit impressive how syntax suggestions get more and more
involved and, if you'll forgive me for saying, ridiculous as the
conversation continues. This is starting to get truly nutty.
What I've done in my projects is simply extend the pattern of 0x... for
hexadecimal literals in C to 0b... for binary, 0o... for octal, 0d...
for decimal (though redundant as that's the default), and so on. (Go
crazy and add 0t... for trinary and 0q... for quaternary if you feel
like it.) To me this always seemed elegant, simple, and understandable.
If arbitrary radix values is what's desirable, then some syntax like
<radix>r<value>
(e.g., 8r024222570 for an octal number which represents a very lame
joke) would work, but seems to me like huge overkill. A normal string
literal coupled with a "constructor" type function would seem far more
appropriate -- and we already have that with `int`.
As for large literals, I'd go with having spaces indicate automatic
concatenation (though only the first in the series can indicate the
radix, whichever method you choose above). It's the same as for
strings, and it's the common SI recommendation for thousands separators
anyway.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
The little I know, I owe to my ignorance.
-- Sacha Guitry
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