Trimming of a text number that's all zeros when the number pattern has a sign char at the end
Hi all, I've hit an interesting case revolving around trimming and number patterns that doesn't seem quite sane to me. Consider an element with the following properties: textTrimKind='padChar' textNumberPadCharacter='0' textNumberPattern='0000+;0000-' So we have the sign character at the end of the representation. Now, imagine that the data being parsed is "0000+". The relevant rules from the DFDL specification are: Section 13.2 on textTrimKind When 'padChar', the element is trimmed of the dfdl:textStringPadCharacter, dfdl:textNumberPadCharacter, dfdl:textBooleanPadCharacter or dfdl:textCalendarPadCharacter depending on the type of the element. Section 13.6 on textNumberPadCharacter When parsing, if the pad character is '0' and the SimpleContent region consists entirely of '0' characters, then the last remaining '0' is not trimmed and a single '0' is the result of the trimming. This rule also applies when the pad character is a DFDL character entity equivalent to '0'. This rule does not apply when the pad character is any other character nor when a pad byte is specified. Section 13.6.1 Describes all of the pattern syntax. In our hypothetical case, the content region is not all zeros, as it ends in '+'. This means that the rule in section 13.6 does not apply and we only apply the rule in 13.2. This results in us trimming away all of the zeros and ending up with '+'. This then doesn't parse as a number. The problem seems to be that the rule in Section 13.6 doesn't take into account that the suffix of the pattern can result in text in the content region that isn't part of the digits of the number. Should the rule under section 13.56 be something more like this... When parsing, if the pad character is '0' and the SimpleContent region consists entirely of '0' characters, or the SimleContent region consists of a string of '0' characters followed by non-digit characters, then the last remaining '0' is not trimmed and a single '0' is the result of the trimming. This rule also applies when the pad character is a DFDL character entity equivalent to '0'. This rule does not apply when the pad character is any other character nor when a pad byte is specified. Thoughts? Andy Andy Edwards - IBM Integration Bus - DFDL Email: andy.edwards@uk.ibm.com Snail Mail: MP211, Hursley park, Hursley, WINCHESTER, Hants, SO21 2JN Tel int: 247222 Tel ext: +44 (0)1962 817222 Desk: DE3 V17 The Feynman problem solving Algorithm 1) Write down the problem 2) Think real hard 3) Write down the answer -- Murray Gell-mann in the NY Times 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
Andy I agree that the existing words do not cover all the scenarios. Your proposed words are on the right track but only cover left trimming a right justified text number. We need something that is independent of justification and can handle patterns where there is quoted text as well as signs. One can envisage some bizarre scenarios. Eg, Text number pattern is "#0'000'" - an attempt to divide by 1000 using the pattern. DFDL parser would trim everything except 1 zero which would not match the pattern which expects at least 3 zeros. Trimming happens before pattern is looked at so I don't think we could cater for this (if we even wanted to). Perhaps we should say: When parsing, if the pad character is '0' and dfdl:textTrimKind is 'padChar' then if the SimpleContent region is trimmed so that the removal of a '0' character leaves the next character other than a digit, the last '0' character is re-instated and not trimmed. This rule also applies when the pad character is a DFDL character entity equivalent to '0'. This rule does not apply when the pad character is any other character nor when a pad byte is specified. That means that "000,000,123" would end up as "0,000,123" instead of ",000,123" today and "0000.025" would end up as "0.025" instead of ".025" today but I think that is good. Regards Steve Hanson Architect, IBM DFDL Co-Chair, OGF DFDL Working Group IBM SWG, Hursley, UK smh@uk.ibm.com tel:+44-1962-815848 From: Andrew Edwards/UK/IBM@IBMGB To: DFDL-WG <dfdl-wg@ogf.org> Date: 30/10/2014 16:43 Subject: [DFDL-WG] Trimming of a text number that's all zeros when the number pattern has a sign char at the end Sent by: dfdl-wg-bounces@ogf.org Hi all, I've hit an interesting case revolving around trimming and number patterns that doesn't seem quite sane to me. Consider an element with the following properties: textTrimKind='padChar' textNumberPadCharacter='0' textNumberPattern='0000+;0000-' So we have the sign character at the end of the representation. Now, imagine that the data being parsed is "0000+". The relevant rules from the DFDL specification are: Section 13.2 on textTrimKind When 'padChar', the element is trimmed of the dfdl:textStringPadCharacter, dfdl:textNumberPadCharacter, dfdl:textBooleanPadCharacter or dfdl:textCalendarPadCharacter depending on the type of the element. Section 13.6 on textNumberPadCharacter When parsing, if the pad character is '0' and the SimpleContent region consists entirely of '0' characters, then the last remaining '0' is not trimmed and a single '0' is the result of the trimming. This rule also applies when the pad character is a DFDL character entity equivalent to '0'. This rule does not apply when the pad character is any other character nor when a pad byte is specified. Section 13.6.1 Describes all of the pattern syntax. In our hypothetical case, the content region is not all zeros, as it ends in '+'. This means that the rule in section 13.6 does not apply and we only apply the rule in 13.2. This results in us trimming away all of the zeros and ending up with '+'. This then doesn't parse as a number. The problem seems to be that the rule in Section 13.6 doesn't take into account that the suffix of the pattern can result in text in the content region that isn't part of the digits of the number. Should the rule under section 13.56 be something more like this... When parsing, if the pad character is '0' and the SimpleContent region consists entirely of '0' characters, or the SimleContent region consists of a string of '0' characters followed by non-digit characters, then the last remaining '0' is not trimmed and a single '0' is the result of the trimming. This rule also applies when the pad character is a DFDL character entity equivalent to '0'. This rule does not apply when the pad character is any other character nor when a pad byte is specified. Thoughts? Andy Andy Edwards - IBM Integration Bus - DFDL Email: andy.edwards@uk.ibm.com Snail Mail: MP211, Hursley park, Hursley, WINCHESTER, Hants, SO21 2JN Tel int: 247222 Tel ext: +44 (0)1962 817222 Desk: DE3 V17 The Feynman problem solving Algorithm 1) Write down the problem 2) Think real hard 3) Write down the answer -- Murray Gell-mann in the NY Times 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 -- dfdl-wg mailing list dfdl-wg@ogf.org https://www.ogf.org/mailman/listinfo/dfdl-wg 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
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Andrew Edwards -
Steve Hanson