Question

If there are multiple date fields that have the same constraint or multiple text-area with the same constraint

Is it possible to reuse the constraint used by a bind, across similar constraints?

say text-area 1 has constraint

if(string-length(.) > 500)
    then substring(.,1,500)
else .

and text-area 2 has constraint

if(string-length(.) > 500)
    then substring(.,1,500)
else .

is it possible to have the constraint at a common location and at each bind call the particular constraint and reuse the code?

Answer 1

You can declare a single bind where the nodeset expression points to the two nodes corresponding to your two text areas. For instance:

<bind nodeset="/my-root/(text-area-1 | text-area-2)" constraint="…"/>

(In the future, a capability to define functions that are more like reusable XPath expressions might be added to XForms, allowing you to also easily reuse XPath expressions in other situations.)