29393 2016-01-26 12:03:34 +0000 Include a convenience operator for applying a function to each item in a sequence 2016-01-26 19:36:35 +0000 1 1 1 Unclassified XPath / XQuery / XSLT XQuery 3.2 Use Cases and Requirements Working drafts PC Linux NEW P2 enhancement --- 1 dk jonathan.robie mike public-qt-comments oldest_to_newest 124712 0 dk 2016-01-26 12:03:34 +0000 XQuery 3.1 introduces the arrow operator to apply a function to an item in a much more readable way. In the same spirit, I would like to apply a function to items in a sequence in such a nice and easily readable way. Suppose, we have a sequence ("a", "b", "c") and we want to get a sequence of upper-case letters as a result. So using the ! operator we can get each item in the sequence and using the arrow operator we can apply the upper-case function. This will result in the following code: ("a", "b", "c") ! (. => upper-case()) which isn't really easier readable anymore because of the required parenthesis. It would be much nicer if we could add an operator, lets say ==>, which would apply the function for each item in the sequence, so we would simply write: ("a", "b", "c") ==> upper-case() This gets even more relevant if the expression is longer. Lets take the example from the spec for the arrow operator at https://www.w3.org/TR/2014/WD-xquery-31-20140424/#id-arrow-operator: tokenize((normalize-unicode(upper-case($string))),"\s+") Suppose, instead of a $string we have a $sequence. Currently, we would have to write: $item ! (. =>upper-case()=>normalize-unicode()=>tokenize("\s+")) With a new operator this would change to $item==>upper-case()=>normalize-unicode()=>tokenize("\s+") which removes difficult to read and nested parenthesis. So to sum up, this double arrow operator is a postfix operator that applies a function to each item in a seuqnece, using each item as the first argument to the function.] If $s is a sequence and f() is a function, then $s==>f() is equivalent to $s ! f(.) or $s ! (. => f()) 124718 1 jonathan.robie 2016-01-26 17:33:33 +0000 I'm moving this to 3.2 (future versions). It's too late for the current CR. 124720 2 mike 2016-01-26 19:36:35 +0000 There's always ("a", "b", "c") => for-each(uppercase#1)