Re: floating point support (was Re: suspend())

• Date: Mon, 29 Jan 1996 14:36:28 PST
• From:
  hpa@trantor.storm.net (H. Peter Anvin)
• Content-Type: text
• Newsgroups: local.moo
• Organization: Where Stormnet meets the Internet
• References: <c=US%a=_%p=msft%l=RED-77-MSG960129135019IA004501@red-02-imc.itg.microsoft.com>

In article <SPAM> Roger Crew  <rfc@microsoft.com> wrote:
> 
> Whatever you do, please do *NOT* put in implicit coercions.  
> For example, in
>
>  a = 5.0;
>  b = 3;
>  c = a / b;
>
> the third line should be throwing an error.  It may seem convenient to have
> an implicit coercion in there, but in the long run this will lead to 
> error-prone code with truncations silently occurring where you least
> expect them. 
>
> People seem to have this idea that, because integers can be viewed as
> a subSET of the reals, that integers, as a datatype, should be a
> subTYPE of the real/float datatype, and it just ain't so... (capsule
> summary: it's not the sets of elements that matters so much as the
> sets of OPERATIONS that you want to be able to use; sin is not a
> sensible operation to use on integers ($trig_utils notwithstanding),
> nor is % a sensible operation to use on floats; end of story).

I disagree.  I think implicit promotions are very useful.  Implicit
*demotions* are not.  % is a perfectly sensible operation on floats
(returning a floating-point number, e.g. 5.5 % 3 == 2.5).

	-hpa
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• Re: floating point support (was Re: suspend())
• From: Jay Carlson <nop@k2.ccs.neu.edu>

• floating point support (was Re: suspend())
• From: Roger Crew <rfc@microsoft.com>

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