1292 2005-05-03 13:19:37 +0000 [F&O] Cast xs:duration to xs:string 2005-09-29 10:43:30 +0000 1 1 1 Unclassified XPath / XQuery / XSLT Functions and Operators 1.0 Last Call drafts All All CLOSED FIXED P2 normal --- 1 joannet ashok.malhotra public-qt-comments oldest_to_newest 3594 0 joannet 2005-05-03 13:19:37 +0000 According to section 17.1.2 "Casting to xs:string and xdt:untypedAtomic" of the F&O spec, if a datatype is not listed in this section, and it does not have a canonical representation defined in Schema (which is the case for xs:duration), then an "implementation dependent canonical representation may be used". According to schema 1.0, "The value space of duration is a six-dimensional space" According to schema 1.1, "Durations can be modeled in at least two ways: as six- property tuples (...) or as two-property tuples" For example: cast xs:duration('P1Y13M40DT1H 61M1S') to xs:string An implementation would likely produce one of the following results: 1. six-property model = P1Y13M40DT1H 61M1S (no change) 2. two-property model = P25MT3463261S (months and seconds) 3. normalize based on xdt:yearMonthDuration and xdt:dayTimeDuration = P2Y1M40DT2H1M1S Since xs:duration is a built-in type and casting to string is a common operation, casting from xs:duration to xs:string or xdt:untypedAtomic should not be implementation dependent. Suggested Resolution: 3. normalize based on xdt:yearMonthDuration and xdt:dayTimeDuration New bullet in section 17.1.2 Casting to xs:string and xdt:untypedAtomic If ST is xs:duration, then let SYM be SV cast as xdt:yearMonthDuration, and let SDT be SV cast as xdt:dayTimeDuration; Then the next intermediate value, TYM, be SYM cast as TT, and let TDT be SDT cast as TT. If TYM is "P0M", then TV is TDT. Otherwise, TYM and TDT are merged according to the following rules: 1. If TDT is "PT0S", then TV is TYM 2. Otherwise, TV is the concatenation of all characters in TYM and all characters except the first "P" and the optional negative sign in TDT. Joanne [on behalf of XTTF]