XPath 2.0 type annotations

From W3C XForms Group Wiki (Public)
(Redirected from Alignment with XPath 2.0)

ErikBruchez to start

An XForms implementation based on XPath 2.0 could also make great use of type annotations. Right now, if you write:

  <xf:bind nodeset="foo" type="xs:decimal"/>
  <xf:bind nodeset="bar" calculate="../foo div 2"/>

then the xs:decimal type is not used at all by the @calculate expression.

XPath 2.0 OTOH has a notion of "typed value", which is used in "Arithmetic expressions, Comparison expressions, Function calls and returns, Cast expressions". [1] So in the same way that a Schema-aware XSLT 2.0 implementation can use the type information, an XForms implementation could use it too. In the example above, ../foo will first be atomized to an xs:decimal value, as if you had written xs:decimal(../foo). This can be very powerful and avoid a lot of casting of numeric values and dates in particular.