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Subject: RE: [office-formula] Re: (fwd) Should OpenFormula BASE() and DECIMAL() definitionslist character set?
Assuming this was intended for the list as well... ___________________________ "Dennis E. Hamilton" <email@example.com> wrote on 05/06/2009 05:57:16 PM: > > RE: [office-formula] Re: (fwd) Should OpenFormula BASE() and DECIMAL > () definitions list character set? > > Yes, I meant that encoding parameter. > > - Dennis > > Here's more thinking about that. I am doing this off the top of my head > without digging out a recent draft of OpenFormula, so I apologize if I am > covering well-worn ground: > > 1. It seems reasonable to me that OpenFormula be expressed in terms of > Unicode (not an encoding), which means it also doesn't have anything to say > about XML character entities or anything like that. > Yes. > I don't know enough about the OpenFormula specification to know how any > character-escaping (if any) is handled. But that could be kept at the > Unicode level, without reference to an encoding. > There are several levels of "encoding": 1) Unicode level mapping of Unicode strings into bytes. 2) XML level format, including the use of numerical character entities, etc. 3) Any OpenFormula level level escaping. For example, I think we have an UPPER() function to turn each character in a string to capital case. Well, if strings parameters are delimited by quotation marks, how do we escape a quote literal in the string? I'm assuming we define OpenFormula at that 3rd level only, at least within the OpenFormula part. But in the main part we can say table:formula is an xsd:string, with a value that is a conforming OpenFormula expression. Calling it xsd:string in an XML file triggers the other constraints at levels 1 and 2 in the above model. > 2. One consequence of taking this approach is that one has to be cognizant > of the fact that the formulas may be carried as attribute values in > XML-based implementations and they will (1) have to be represented in the > character-set encoding of that representation and (2) appropriately > contained in quotations where the extent of the formula is unambiguously > determined. How that's done would seem to fall entirely on the > implementation that carries the formulas, not OpenFormula itself. ODF 1.2 > might need to say something about it, in its definition for table-cell > formula, but probably not if XML attribute-value representation rules and > the use of attribute value-type string are sufficient. > As above. I think saying it is an attribute value of type xsd:string should be sufficient. An informative example might be useful as an illustration. > 3. I think it would be useful to know, in a pure-Unicode approach, what > minimum set of Unicode characters are required to be usable to express > OpenFormula and what others might be allowed (e.g., in the rules for names > and the expression of string-valued literals used within a formula). A BNF > grammar that appealed to Unicode character categories could set the > ceilings, but it is useful to know if there is a different floor. > Function that take a string parameter may be unconstrained other than the constraints on them being in allowable in attribute values. It might be worth a quick look at XPath, which also has a simple expression language with a formula library represented in XML attribute values, to see how they handle this. We can probably copy their approach. -Rob > -----Original Message----- > From: firstname.lastname@example.org [mailto:email@example.com] > Sent: Wednesday, May 06, 2009 14:24 > To: firstname.lastname@example.org > Cc: 'David A. Wheeler'; 'Eike Rathke'; 'Michael Brauer'; 'OASIS ODFF SC'; > email@example.com > Subject: RE: [office-formula] Re: (fwd) Should OpenFormula BASE() and > DECIMAL() definitions list character set? > > I'm assuming you mean the character encoding expressed at the XML level, > such as: > > <?xml version="1.0" encoding="ISO-8859-1"?> > > Do we need to say anything more here than what the XML Recommendation > says? What else would you have? Restrict encoding to an enumerated > subset of encodings? > > In any case, I think things are cleaner if we keep OpenFormula independent > of XML, since there is not necessary connection to markup at all, if we > partition this right. > > OpenFormula should define conformance for two things: > > 1) The syntax of a conforming OpenFormula expression, which would be > expressed as BNF and other constraints on a Unicode string > > 2) Constraints on the values returned by a conforming OpenFormula > expression > > -Rob > > > "Dennis E. Hamilton" <firstname.lastname@example.org> wrote on 05/06/2009 > 03:38:32 PM: > > > > > Subject: > > > > RE: [office-formula] Re: (fwd) Should OpenFormula BASE() and DECIMAL > > () definitions list character set? > > > > Does there need to be something said about what happens when the > content.xml > > (or any other XML file) uses an encoding other than one for Unicode? My > > understanding is that other encodings are referenced to Unicode in and > out, > > but not sure whether this has been clarified anywhere in ODF > specifications > > nor in OpenFormula, where the ability to correctly interpret and to > preserve > > on export may be impaired (though hopefully not for any of the printable > > Basic Latin characters of Unicode). > > > > - Dennis > > > > -----Original Message----- > > From: email@example.com [mailto:firstname.lastname@example.org] > > Sent: Wednesday, May 06, 2009 11:34 > > To: David A. Wheeler; Eike Rathke; Michael Brauer; OASIS ODFF SC; > > email@example.com > > Subject: [office-formula] Re: (fwd) Should OpenFormula BASE() and > DECIMAL() > > definitions list character set? > > > > I checked with our local Unicode guru, to make sure we were expressing > > this right. He confirmed that it is correct to refer to the "value > space" > > as Unicode "characters" and "strings", and the serialized versions as > > "encoded characters". > > > > [ ... ] > > > > > --------------------------------------------------------------------- > 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 >