Here's the revised decimal supplement again for final approval. Please can we discuss on the call today for inclusion in draft 33. This has been updated to reflect the debate below around properties dfdl:decimalFormat and dfdl:integerFormat (because either could be used with xs:int and xs:decimal, and at runtime the parser does not know which one to apply). So dfdl:decimalFormat has been removed, and replaced by dfdl:numberFormat - defined below. Property Name Description numberFormat String Valid values are ?text?, ?zoned?, ?packed?, ?BCD?, 'twosComplement' When the representation is ?text? then the allowable values are ?text? and ?zoned?. When the representation is ?binary? then the allowable values are ?packed?, ?BCD? and 'twosComplement'. I'd also like to propose that we rename dfdl:defineNumberFormat to dfdl:defineTextNumberFormat, to prevent confusion. The other change is around the packed decimal convention, sometimes used, that zero is indicated by all bytes being hex zero, even though this is not technically a valid packed decimal number. I had said that on parsing, whether to tolerate this is governed by the numberCheckPolicy property, and on unparsing, this convention is not used. That won't work because we are talking about (binary) packed decimals and numberCheckPolicy is a property within (text) dfdl:defineNumberFormat. One solution is to move numberCheckPolicy outside of dfdl:defineNumberFormat and have it apply to both text and binary numbers. However it can be observed that numberCheckPolicy is getting rather bloated and is covering several behaviours. There's yet another behaviour that could be added - the TX team review want a dfdl:defineNumberFormat property called numberZeroRep to handle special zero representations. That's fine - but on parsing whether to allow just the zero rep or both the rep and '0' is a requirement from TX - which we could accomodate by extensing numberCheckPolicy. Question is, are we overloading numberCheckPolicy, or is it time to make it more granular? Regards Steve Hanson Programming Model Architect WebSphere Message Brokers Hursley, UK Internet: smh@uk.ibm.com Phone (+44)/(0) 1962-815848 ----- Forwarded by Steve Hanson/UK/IBM on 16/07/2008 12:15 ----- Steve Hanson/UK/IBM 09/04/2008 15:44 To <mbeckerle.dfdl@gmail.com> cc dfdl-wg@ogf.org Subject RE: Fw: DFDL Decimal - proposal - correcting wrong attachment Hi Mike - answers in-line below. Regards, Steve Steve Hanson Programming Model Architect WebSphere Message Brokers Hursley, UK Internet: smh@uk.ibm.com Phone (+44)/(0) 1962-815848 "Mike Beckerle" <mbeckerle.dfdl@gmail.com> 09/04/2008 15:05 Please respond to <mbeckerle.dfdl@gmail.com> To Steve Hanson/UK/IBM@IBMGB cc <dfdl-wg@ogf.org> Subject RE: Fw: DFDL Decimal - proposal - correcting wrong attachment Thanks for these clarifications. Do we have a way to represent ?unpacked? decimal numbers. This is like zoned, except the ?zones? are zero instead of ?F? (in ebcdic encodings). <smh>No we don't. Neither MRM nor TX support that. Have you seen such an example? Is it encoding sensitive? Also, can a BCD number have a sign? <smh>What we are calling a BCD can not have a sign, as far as I know. That's where packed decimal comes in. ?mikeb From: Steve Hanson [mailto:smh@uk.ibm.com] Sent: Wednesday, April 09, 2008 10:00 AM To: mbeckerle.dfdl@gmail.com Cc: 'Mike Beckerle'; Alan Powell; Ian W Parkinson Subject: RE: Fw: DFDL Decimal - proposal - correcting wrong attachment Hi Mike - answers in-line below. Regards, Steve Steve Hanson Programming Model Architect WebSphere Message Brokers Hursley, UK Internet: smh@uk.ibm.com Phone (+44)/(0) 1962-815848 "Mike Beckerle" <mbeckerle.dfdl@gmail.com> 09/04/2008 01:43 Please respond to <mbeckerle.dfdl@gmail.com> To Steve Hanson/UK/IBM@IBMGB, Alan Powell/UK/IBM@IBMGB cc Ian W Parkinson/UK/IBM@IBMGB, 'Mike Beckerle' Subject RE: Fw: DFDL Decimal - proposal - correcting wrong attachment I prefer one property dfdl:numberFormat, the valid values of which depend on dfdl:representation <smh>The advantage of two properties is that you can set scoping for text and binary numbers separately. I like the analysis that text formats are ones which depend on encoding, and not byteOrder, and binary depend on byte order, and NOT encoding. <smh>Me too. There?s also format specifiers for floating point. Should those also go on here, be allowed only for representation=?binary?? <smh>I did think about this, but I think we are better off keeping floats separate. Otherwise people might think you can declare a logical float to be rep'd by physical integer. MRM allows this, and I wish it didn't. It also exacerbates the problem noted above - I couldn't set a default float format, which is something that would almost certainly never vary within a data stream. The rest of the proposal looks fine. I found decimalVirtualPoint an odd name, but it is clear and obeys the conventions. <smh>I agree it's a bit odd. An alternative is 'decimalimpliedPlaces' which uses TX terminology - but that doesn't match the 'V' pattern character we are proposing in the ICU pattern (which matches COBOL) I was a bit unclear on how do you represent an unsigned packed decimal. This is common. There is no sign nibble at all. It lets you do an even number of digits. MMDDYY is commonly this, 3 unsigned packed numbers. <smh>What you have described is dfdl:numberFormat="BCD". An unsigned packed decimal is dfdl:numberFormat="packed" with the sign nibble always unsigned, so dfdl:packedDecimalSignCodes="F F F". ?mikeb From: Steve Hanson [mailto:smh@uk.ibm.com] Sent: Wednesday, April 02, 2008 11:54 AM To: Alan Powell Cc: Ian W Parkinson; Mike Beckerle Subject: Re: Fw: DFDL Decimal - proposal - correcting wrong attachment Alan, Ian and myself reviewed this today. The main issue was that the loss of dfdl:representation="decimal" means that it is no longer clear when to use dfdl:integerFormat and dfdl:decimalFormat, because an xs:decimal can have a binary integer rep and an xs:int can have a binary decimal rep. It was noted that both IBM models (MRM and TX type tree) handle this by having a single property. I don't want to re-introduce rep=decimal, I think we shoiuld stick with text (implying encoding sensitive) and binary (potentially byte order sensitive). Options: a) One property dfdl:numberFormat with values "text", "zoned", "packed", "BCD", "twosComplement", "onesComplement", "signMagnitude". - "text" and "zoned" when dfdl:representation="text" - "packed", "BCD", "twosComplement", "onesComplement", "signMagnitude" when dfdl:representation="binary" Number xs:int, xs:decimal text => numberFormat xs:float, xs:double text => xs:int, xs:decimal binary => numberFormat xs:float binary => floatFormat b) Two properties dfdl:textNumberFormat and dfdl:binaryNumberFormat, allowable enums split as above. - this means the existing dfdl:textNumberFormat property gets renamed to dfdl:textNumberPattern or dfdl:textNumberScheme Number xs:int, xs:decimal text => textNumberFormat xs:float, xs:double text => xs:int, xs:decimal binary => binaryNumberFormat xs:float binary => floatFormat Other suggestions? Regards, Steve Steve Hanson WebSphere Message Brokers Hursley, UK Internet: smh@uk.ibm.com Phone (+44)/(0) 1962-815848 Alan Powell/UK/IBM 28/03/2008 16:45 To Steve Hanson/UK/IBM@IBMGB cc Ian W Parkinson/UK/IBM@IBMGB, mbeckerle@oco-inc.com Subject Re: Fw: DFDL Decimal - proposal - correcting wrong attachmentLink Steve Technically seems OK. Need quite a bit of editorial work before it can be included in the spec which I have started. Alan Powell MP 211, IBM UK Labs, Hursley, Winchester, SO21 2JN, England Notes Id: Alan Powell/UK/IBM email: alan_powell@uk.ibm.com Tel: +44 (0)1962 815073 Fax: +44 (0)1962 816898 From: Steve Hanson/UK/IBM To: mbeckerle@oco-inc.com Cc: Alan Powell/UK/IBM, Ian W Parkinson/UK/IBM Date: 28/03/2008 13:59 Subject: Fw: DFDL Decimal - proposal - correcting wrong attachment Here's an attempt at a revised decimal supplement, that takes into account the stuff in my mail below. [attachment "ggf-dfdl-supplement-advanced-decimal-properties-v1.0-003.doc" deleted by Alan Powell/UK/IBM] Some discussion points: 1) I've removed the representation 'Decimal' - a decimal is either 'Text' or 'Binary'. Property decimalFormat says whether it is text or zoned (for text) or packed or BCD (for binary). 2) There's no need for a decimalSigned property, as zoned uses numberPattern for this, BCD is always unsigned, and packed indicates this via sign code 3) I've added VDP property for BCD and packed - zoned uses numberPattern for this. However, VDP property is also needed for binary integers - this is missing from spec. COBOL PIC 99V99 COMP will create an xs:decimal with binary integer rep, so we need to support this. I suggest we have a single VDP property that applies to all binary reps that can be used to represent xs:decimal. So my VDP property gets removed to main spec. 4) The resultant properties are less than before. I'm not sure that a separate supplement is justified. 5) I would like to remove numberCheckPolicy from dfdl:DefineNumberFormat, and make it a separate property. Two reasons: - I think the decision to use strict/lax checking is not an attribute of the number format but more an attribute of the schema as a whole. - It means we can control packed decimal sign nibble oddities with the same property as other strict/lax number checking, Let's review on next OGF WG call. Regards, Steve Steve Hanson Programming Model Architect WebSphere Message Brokers Hursley, UK Internet: smh@uk.ibm.com Phone (+44)/(0) 1962-815848 ----- Forwarded by Steve Hanson/UK/IBM on 28/03/2008 12:33 ----- Steve Hanson/UK/IBM 27/03/2008 15:29 To Mike Beckerle (Work) cc Subject DFDL Decimal - proposal Hi Mike I've finally got round to looking at the decimal supplement, and I'd like to get your opinion on something. The WTX team have been reviewing draft 031 and had the following observation (actually they had quite a few good ones, and when they've finished we need to discuss them all on a OGF WG call). "13.3. Is a zoned decimal textual or non-textual? If all overpunched variants result in well-known characters then the data is scannable and therefore more like a textual field." It turns out that the type hierarchy in TX for decimal looks like below. They consider Zoned as text as it always consists of reasonable characters and is subject to encoding conversion, padding, justification, etc. There's a lot of appeal in that. It's always bothered me a bit that MRM viewed it as a binary type. Number -> Character -> Decimal (meaning text decimal) Integer (meaning text integer) Zoned -> Binary -> Integer (meaning binary integer) Float Packed BCD Also, their Zoned does not have separate sign option. They point out that a separate signed Zoned is just a Text decimal. And they are correct. We got the separate sign thing from MRM, which after some digging turns out to have got it from the CAM Type Descriptor model, which had no other way of representing a text decimal number with a separate sign. As part of my rework of the decimal supplement, I'd like to take both these into account. The implications are: - Zoned => overpunched only - Zoned decimal can pick up on the textNumberxxx properties, including textNumberFormat => use the numberPattern (ie, ICU pattern) property to say which end the (overpunched) sign goes => can get away without a separate pattern language for binary decimals, which as you point out has endian-ness issues - Binary decimals are packed and BCD - There are a lot fewer properties for decimals - dfdl:representation = "text" can have subdivisions - that's not occurred until now (we could think about making dfdl:representation = "xml" a subdivision of "text"?) If you think there is merit in this approach then let me know by return and I'll see if I can write something up tomorrow. I'm WAH on +44-1794-340899 if you want to discuss. Your "crazy idea" below is interesting - but I think is a tooling thought rather than a core spec thing. (Sorry about call yesterday - I thought I mailed something out a couple of calls ago about DST mismatch, but perhaps I didn't). Regards, Steve Steve Hanson Programming Model Architect WebSphere Message Brokers Hursley, UK Internet: smh@uk.ibm.com Phone (+44)/(0) 1962-815848 ----- Forwarded by Steve Hanson/UK/IBM on 27/03/2008 15:04 ----- Mike Beckerle/Worcester/IBM@IBMUS 21/11/2007 15:26 To Steve Hanson/UK/IBM@IBMGB cc DFDL-Technical-Core, Suman Kalia/Toronto/IBM@IBMCA Subject DFDL Decimal - was Re: DFDL & length prefixes - proposalLink I think decimal has signed and unsigned variants based on dfdl:decimalSigned boolean. If this is false then it's unsigned and packedUnsignedRep specifies the sign nibble used for unsigned. The doc doesn't specify that one can say "" for this indicating no sign nibble at all. I've been rereading the decimal properties supplement and starting v002 of it based on changes to dfdl:representation in the core spec. This needs a general clean up. There's errors here in that there is a decimalType="zoned", or "packed" or "BCD" and also a bcdIsPacked, and bcdUnpackedRep="ebcdic", which is the same as zoned I think. We need there to be one way to express these things. Right now the bias is a set of orthogonal flags: signed or unsigned, what's the sign nibble for unsigned, what sign nibbles for signed, packed or unpacked, what's in the zones - the unused nibbles - (ebcdic, i.e., "F", ascii, i.e., "3", or zero - but that's not enough as I've seen data with "2" in the zones - some non IBM cobol compiler does this.). A better choice may be to specify decimalType as a larger enum which includes most of these properties, so that we don't end up with too much ability to express variants that have simply never existed. A list of the use cases needs to be added to the doc also. Here's a few: -1234 as expressed as bytes in hex in increasing position order, i.e., LSB first. packed ibm, signed, D01234 zoned ibm, overpunched leading sign D1F2F3F4 (are signs usually leading or trailing.... I think trailing actually.) big endian zoned ascii, ascii-translated overpunched leading sign 4A323334 (yuck - so much for treating decimal as "binary" data). Here's a crazy idea: I believe there is a set of magic numbers which if you give me their translations in bytes, I can determine exactly what the encoding properties are. E.g., if you give me the bytes for +0000, -1234, +789 I believe I can determine all of the properties. This might be a better way to specify decimal formats. I.e., give me those byte patterns expressed as hex, and I reverse engineer all the property settings. e.g., decimalFormat="+0000=C00000-1234=D01234 +789=C789" (signed, packed, leading sign, padded to even number of nibbles, big endian, zero carries a sign, "C" is plus, "D" is minus) or decimalFormat="+0000=00000000 -1234=D1F2F3F4 +789=C7F8F9" (ebcdic zoned, leading overpunched sign, big endian, zero is allowed to have zero as sign and all zero bytes, "C" is plus, "D" is minus) This may make more sense for the tooling than the DFDL language though. I.e., point it at some data and it tries to guess these properties. Mike Beckerle STSM, Architect, Scalable Computing IBM Software Group Information Platform and Solutions Westborough, MA 01581 direct: voice and FAX 508-599-7148 assistant: Pam Riordan priordan@us.ibm.com 508-599-7046 Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU