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This page is part of the web mail archives of SRFI 70 from before July 7th, 2015. The new archives for SRFI 70 contain all messages, not just those from before July 7th, 2015.

*To*: schlie@xxxxxxxxxxx*Subject*: Re: Nitpick with FLOOR etc.*From*: Aubrey Jaffer <agj@xxxxxxxxxxxx>*Date*: Sat, 16 Jul 2005 13:43:30 -0400 (EDT)*Cc*: sperber@xxxxxxxxxxxxxxxxxxxxxxxxxxx, srfi-70@xxxxxxxxxxxxxxxxx*Delivered-to*: srfi-70@xxxxxxxxxxxxxxxxx*In-reply-to*: <BEFE3FB8.AD89%schlie@xxxxxxxxxxx> (message from Paul Schlie on Sat, 16 Jul 2005 04:38:16 -0400)*References*: <BEFE3FB8.AD89%schlie@xxxxxxxxxxx>

| Date: Sat, 16 Jul 2005 04:38:16 -0400 | From: Paul Schlie <schlie@xxxxxxxxxxx> | | > If the stipulation that inexacts args produce inexacts results takes | > priority over finding the closest integer, then only inexact integers | > are eligible. For an implementation having IEEE-754 64.bit flonum | > inexacts: | > | > procedure #i-/0 #i+/0 | > ========= ===== ===== | > | > floor error 179.76931348623157e306 | > | > ceiling -179.76931348623157e306 error | > | > truncate -179.76931348623157e306 179.76931348623157e306 | > | > round -179.76931348623157e306 179.76931348623157e306 | | - are you proposing that a run-time error must be signaled; or more | reasonably only that it may, and/or alternatively return -1/0 +1/0 ? | [which I tend to view as being equivalent to #i-/0, #i+/0] My chart proposed no change to R5RS. These large magnitude numbers are simply those IEEE-754 numbers satisfying the R5RS descriptions of these procedures. Oops! -- (floor #i-/0) and (ceiling #i+/0) are not automatically allowed to be errors by R5RS because these procedures are expected to return inexacts for inexact arguments. I will add to the description: For an inexact argument x, it is an error if there is no inexact integer which satisfies the procedure description; for example calling `(floor -/0.)' or `(ceiling +/0.)' in an implementation having IEEE-754 64.bit flonum inexacts. | - what about -0/1, +0/1 ? All four functions return zero for an argument of zero. There are no infinitesimals in SRFI-70. | - should (= (floor x) (/ (ceiling (/ x))) [or reasonable approximation] ? (let ((x -5)) (= (floor x) (/ (ceiling (/ x))))) ==> #f

**References**:**Re: Nitpick with FLOOR etc.***From:*Paul Schlie

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