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What if it is stated in 1788.1 that the result of mixed radix interval literal conversions is system dependent (i.e. not specified in 1788.1)? Thus, if mixed radix interval literal conversions are not used in a program, a program conforming to 1788.1 will run the same on a 1788-conforming system. This difference could be prominently explained in the 1788.1 document. 1788.1 would then be a "subset" of 1788 in the sense that less is specified. Correcting a possible error in 1788 might be another matter. However, is it an actual error (i.e. and inconsistency) or a specification that is inadvisable due to difficulty of implementation? Baker On 08/07/2016 05:09 PM, Michel Hack wrote:
On Sun, 7 Aug 2016 14:21:21 -0700 (PDT), Dima wrote:I believe that interval literal is the only topic where behavior is different.The big deal is that 1788 allows <lower,upper> to specified in mixed radices, and we want to avoid this in 1788.1 because determining whether lower<=upper is difficult -- and in any case, 754 does not support mixed-radix comparisons. We may have made a mistake in allowing mixed-radix interval literals in 1788. In general mixed-radix support is easier in an interval standard than in a pure numeric standard, because we can always enclose a result. It's even easy to support tightest mode for basic arithmetic, except possibly for the unlikely case where both decimal and binary mpfr-based types are used. There should be no prohibition of mixed-radix arithmetic. But literals are a different story, because text input is in fact unbounded-precision. So we have an explicit escape clause, "unable to decide whether interval exists", and I don't think we want that in 1788.1 -- it's complicated. Michel. ---Sent: 2016-08-07 22:25:25 UTC
-- --------------------------------------------------------------- Ralph Baker Kearfott, rbk@xxxxxxxxxxxxx (337) 482-5346 (fax) (337) 482-5270 (work) (337) 993-1827 (home) URL: http://interval.louisiana.edu/kearfott.html Department of Mathematics, University of Louisiana at Lafayette (Room 217 Maxim D. Doucet Hall, 1403 Johnston Street) Box 4-1010, Lafayette, LA 70504-1010, USA ---------------------------------------------------------------