Mapping arrow operator

The expression LHS =!> f() applies the function on the right-hand side to each item delivered by the left-hand side individually. For example (-2 to +2) =!> abs() returns (2, 1, 0, 1, 2). The effect is similar to writing (-2 to +2) ! abs(.), but the operator precedences make it easier to construct a pipeline of operations without parentheses. The rules are similar to the XPath 3.1 arrow operator LHS => f() except that the function is not applied to the value of the left-hand operand as a whole, but to each item individually; it thus combines the functions of => and !, which accounts for the choice of operator symbol.