Hi all, In addition to the other requested specification modifications ("lay dog"s and XPath 1+2) please take a look at the proposed looping modifications. Frustratingly one issue still remains: Dave Meredith has raised the prospect of problems if we advise the use of ranges when performing LoopDouble Exception comparison as effectively it's a green light for inconsistency across implementations (and in some respects mismatching/inaccuracy). As we're strongly recommending the adoption of the IEEE 754 standard decimal floating point arithmetic in implementations I think that this should provide the expected consistency (even if it's consistent inaccuracy!?) without the need for ranges. Alternatively a reversal on my earlier hesitation in the adoption of the jsdl:RangeValue_Type may be required, e.g.
<sweepfunc:LoopDouble substitutes=”sweep:Function” start=”xsd:double” end=”xsd:double” step=”xsd:double” > <sweepfunc:Exception> jsdl:RangeValue_Type </sweepfunc:Exception>* </sweepfunc:LoopDouble>
gef ------------------------------------------ 4.2 LoopInteger function The LoopInteger function provides an ordered list of integer values within the inclusive range specified by the start and end values. The list begins at the start value and contains all subsequent rangebound incremented or decremented values as determined by the step value. A LoopInteger function MAY exclude certain values by including Exception Child elements. This function yields values that are calculated as follows. The first value equals the value of the start value. Any subsequent value is calculated using the following rule: nextValue ::= currentValue + valueOf( step ) If “nextValue” is beyond the range boundary specified by the end value, then “nextValue” is discarded and the LoopInteger function terminates with “currentValue”. If a value for “step” is not given, the default value of “1” MUST be used. ... [unmodified] Implementations handling the LoopInteger function may choose to : - Where possible, predetermine and validate the loop cardinality by inspection prior to running the loop operation, and confirm cardinality post-operation. - Respond appropriately if schematically valid yet questionable values are supplied, e.g. if the value 0 is encountered for step. ... [unmodified] 4.3 LoopDouble function The LoopDouble function provides an ordered list of double datatype values (corresponding to the IEEE double-precision 64-bit floating point type) within the inclusive range specified by the start and end values. The list begins at the start value and contains all subsequent rangebound incremented or decremented values as determined by the step value. ... [unmodified] The permissible value range... ....The following are therefore considered valid xsd:double values : -1E4, 1267.43233E12, 12.78e-2, 12, NaN, -0 and INF . Please note (accuracy advice): The reference to xsd:double datatype values (and double-precision 64-bit floating point types) is solely for the definition of the valid value range and format acceptable in LoopDouble functions. Implementations which process such values should have functionality that most accurately interprets and operates on such a value range and format, e.g. it is strongly recommend that implementations support IEEE 754 standard [1] decimal (base 10) floating point arithmetic, in preference to binary (base 2) arithmetic. Implementations handling the LoopDouble function may choose to : - Where possible, predetermine and validate the loop cardinality by inspection prior to running the loop operation, and confirm cardinality post-operation. - Convert xsd:double datatype values to integer values and implement only integer arithmetic processing. - Determine an acceptable range when comparing equality of a particular loop value against loop Exception values, e.g. an exception may be affirmed if a loop Exception value is within a % range of the loop value. - Encourage consistency in value format, e.g. avoid mixing scientific and non-scientific nomenclature in a LoopDouble element. - Respond appropriately should schematically valid yet questionable values such as NaN, -0, INF, -INF be encountered. Footer note: [1] IEEE 754 - 2008 http://ieeexplore.ieee.org/servlet/opac?punumber=4610933