Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!husc6!spdcc!ima!haddock!karl
From: karl@haddock.ima.isc.com (Karl Heuer)
Newsgroups: comp.lang.c
Subject: Re: binary constants (??)
Message-ID: <15348@haddock.ima.isc.com>
Date: 4 Dec 89 22:41:59 GMT
References: <305@frf.omron.co.jp> <20830@mimsy.umd.edu> <20989@mimsy.umd.edu> <1989Nov29.164913.1794@utzoo.uucp>
Reply-To: karl@haddock.ima.isc.com (Karl Heuer)
Organization: Interactive Systems, Cambridge, MA 02138-5302
Lines: 20

In article <1989Nov29.164913.1794@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes:
>For some reason, I've never had cause to write numbers in (say) base 19.

Interestingly enough, I once needed to write some constants whose natural
radix was 64 (and, due to the context, none of the radix-64 digits would ever
exceed the value of 'Z').  When I tried to make use of the arbitrary-radix
feature built into the language I was using at the time (using the notation
ddddB64), it triggered a compiler bug.

>I wonder if the added generality really buys you anything, given that it
>does introduce a new class of subtle errors.  (How many programs would
>notice if 16r19 was mistyped as 15r19?  Or 19r16?)

It doesn't seem any worse than the problem of accidentally putting a leading
zero on a number intended to be decimal.  Anyway, a partial solution is to
have the compiler optionally warn about the use of an "obscure" radix.

Karl W. Z. Heuer (ima!haddock!karl or karl@haddock.isc.com), The Walking Lint
(Bonus question: identify the language, operating system, and university where
I had use for radix 64.  No, I *don't* mean radix 40 aka RAD50.)