binary constants

[Clive Feather]

[I finally get to follow up to Chris Torek]
In article <20830 at mimsy.umd.edu> chris at mimsy.umd.edu (Chris Torek) writes:
>One of my favourite silly ideas for C is now ruled out by X3J11's
>`#' `stringize' preprocessing operator (or at least, would require
>some other syntax), but it went like this:  Instead of having hex,
>decimal, octal, binary, etc., constant syntaxes, why not have a
>single syntax for `based numbers'?  The initial radix would always
>be decimal; the format would be something like
>	#(base,expr)
>Numbers in the `expr' part would be interpreted in the base given by
>the `base' expression.  Any value from 2 to 36 would be legal for the
>base.  All `numbers' would be of the form
>	[0-9][0-9a-zA-Z]*
>where ordinary digits represent themselves and letters represent digits
>>= 10 in the obvious manner.  (Whether digits greater than the base
>would be legal is essentially irrelevant.)

Algol 68 (yes, some of us once used it) uses the following notation for bit
patterns:

    2r11001000  == 200
    4r3020      == 200
    8r310       == 200
    16rc8       == 200

This could be trivially extended to any base up to 36. It has advantages over
Chris's notation, in that the numbers are already pp-numbers (see the
discussion in comp.std.c), and it doesn't use a new operator.

>The sneaky (or silly) bit is that both `base' and `expr' would be
>arbitrary constant expressions.  This would be useful for obfuscation
>such as
>	   #(3+#(2,#(6,13)-0010),#(5,11)/30)
>which is actually 1.
>(I think.)
You're right - silly is the word :-).


-- 
Clive D.W. Feather
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