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*To*: andyw@ibeam.ht.intel.com, dyer@eagle.sharebase.com*Subject*: Re: bounded, infinite ranges?*From*: dyer@eagle.sharebase.com (Scot Dyer)*Date*: Thu, 22 Oct 92 14:29:10 PDT*Cc*: info-dylan@cambridge.apple.com

Andy Wilson writes: /// Scot Dyer writes: /// --------------------------------------------------------------------- /// /// Again, these unpleasant facts of floating point life could be avoided /// /// if from/up-to/by were constrained to be <rational>. /// /// I think even <rational> might have it's problems... /// --------------------------------------------------------------------- /// /// Rational arithmetic is always exact; maybe not fast, but exact. Yes, but enumerating a finite rational range would be quite time-intensive, and would require some special form, since it wouldn't (in all probability) fit in memory on most machines. Also, generating the members of a rational range in sequential order (each new one greater or lesser for the whole range) is more of a trick than for floats (in my eyes -- but my experience w/ rationals is limitted) I do agree that = should be defined for rationals, tho'. And for indexed loops (ala 'for') a rational restriction is probably best. Either that, or something like C's for, which would really be a 'while' extension. Since the iteration methods are defined for collections, a special version of 'for' could be provided, like '(over <collection> <form>)' (for-each w/ <collection>?) -- Scot

**Follow-Ups**:**bounded, infinite ranges?***From:*Stavros Macrakis <macrakis@osf.org>

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