"arithmetic if":: Re: Feature for the next C version

[John Hascall]

In article <1429 at crdgw1.crd.ge.com> davidsen at crdos1.UUCP (bill davidsen) writes:
 
>someone pointed out, I'm not looking for arithmetic IF, but a way to do
>three separate things based on a value, usually the compare of two
>values in a sort or tree search.
 
>  Some interesting ideas:
>	ifcase
>	  (a < b) code; code;
>	  (a == b) more(code);
>	  (a > b) still(more);
>	endcase;
 
    This reminds my of an exec language I somtimes program in (no, you
    haven't heard of it), where you use:

    cases begin
	case (expression1) statement1
	case (expression2) statement2
	    :
	    :
    end

    And it evaluates each expression in order and executes the (possibly
    compound) statement of the first one (if any) which is true.
    [and you just use "case (true)" at the end for "default:"].

    Of course, neither of these solve the original problem of how to
    execute a 3-way branch with a single expression evaluation.

    Imagine extending the concept:

       if (expr) s1; [else s2;]

    to:

       negative (expr) s1; [zero s2;] [positive s3;]

 
    I can hear the C-purists screaming in agony :-)

John Hascall