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Subject: RE: Unit Prefixes in CONVERT
Actually, I think Patrick's rewording does most of the job. I read it out of context and took it as referring to cells in the spreadsheet rather than the cells of the table that lists the unit symbols. I suppose that is an ambiguity to be discouraged though. -----Original Message----- From: Dennis E. Hamilton [mailto:dennis.hamilton@acm.org] Sent: Friday, April 09, 2010 08:29 To: 'Patrick Durusau' Cc: 'office-formula@lists.oasis-open.org' Subject: RE: Unit Prefixes in CONVERT I think you're right that this means what can be said in the formula and what evaluators do with it. I took these statements to mean that if an evaluator supports conversion on distances, such as CONVERT(N;"ly";"m"), Then it shall also support CONVERT(n;"nly";"km"). That is, the prefixes are on the unit symbols. We should not have anything about cell scaling in OpenFormula. For one thing, the CONVERT function specifies what the understood units of the value are to be in terms of with the "from" parameter. For another, we must not be in a situation where we confuse how a cell's value is *presented* in particular units (as part of formatting for presentation of the cell and acceptance values for the cell) and how a cell's value is *retained* as a dimensionless Number value, at least when that cell is reference in an OpenFormula expression. If cells are not retained as dimensionless values we have a real problem with what formula =1.0 for the cell delivers to a subsequent CONVERT(n;from;to). Perhaps, in that case, we would need something like CONVERT(N;;"km") which works if N is a dimensioned distance value and fails if it isn't? I don't think we want to go down that road at all. For OFFICE-500 I believe we have deferred all treatment and assumption of unit-system tracking as a characteristic of values (and hence data types). This ambiguity calls for a JIRA issue. It is OFFICE-2629 This is also an interesting case for a codefest exercise. - Dennis Of course, there is limited capability of explicit unit tracking. For example, in CONVERT(N;[A17];"km") where it happens that the value of [A17] is the text given by formula ="nly". (My apologies if I should be using ' instead of " here.) -----Original Message----- From: Patrick Durusau [mailto:patrick@durusau.net] Sent: Friday, April 09, 2010 07:37 To: office-formula@lists.oasis-open.org Subject: Re: Fwd: Re: [office-formula] Straw poll - slug (and lightyear) [ ... ] BTW, the "*" made me look for the explanation and I find: Unit symbols in cells marked with * shall support decimal prefixes, and unit symbols in cells marked with † shall support binary prefixes; evaluators should not support prefixes for other unit symbols. I am not going to post a JIRA issue but clearly unit symbols don't support any sort of prefixes. Evaluators might. Re-writing to say: Evaluators shall support decimal prefixes for unit symbols marked with * and binary prefixes for unit symbols marked with †. Evaluators should not support prefixes for other unit symbols. I am not happy with the final sentence but will try to think of a better way to say that. Hope you are having a great day! Patrick WARNING: Technical nitpick ahead: The distance light travels in a year, in a vacuum, *is* exact; the meter is actually defined in terms of speed of light in a vacuum. And while an Earth year isn't exactly 365.25 days, for purposes of a light-year, that's the exact value of the "year". It's not well-documented, but astronomers use this "standard year approximation" of 365.25 days when stating light-years. And since a day is exactly 24*60*60 seconds, this has an exact value. I actually had to track that down, and I'm pretty sure I posted my citations (though I can't remember where they are right now). If anyone knows differently, please let us know now. --- David A. Wheeler --------------------------------------------------------------------- To unsubscribe from this mail list, you must leave the OASIS TC that generates this mail. Follow this link to all your TCs in OASIS at: https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php -- Patrick Durusau patrick@durusau.net Chair, V1 - US TAG to JTC 1/SC 34 Convener, JTC 1/SC 34/WG 3 (Topic Maps) Editor, OpenDocument Format TC (OASIS), Project Editor ISO/IEC 26300 Co-Editor, ISO/IEC 13250-1, 13250-5 (Topic Maps)
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