Schematron conditional validation

Question

I've recently started using schematron to validate xml documents. I'm pretty impressed by it so far, but I've stumbled upon a rule that I can't get to work properly.

I've made a simple example below.

<iso:assert test="ns1:some-element/text() = 'false' and /ns1:same-other-element">Error message</iso:assert>

Basically I want to validate two things, if ns1:some-element/text() contains 'false', ns1:same-other-element should be present, and that validation actually works. However, when ns1:some-element/text() contains something other than false, than I don't care weather ns1:same-other-element is there or not.

At this moment, the rule also fires when ns1:same-other-element is missing and the value of ns1:some-element/text() is not 'false'

Any ideas how to work around this?

Answer 1

Your test needs to evaluate to true in order to pass validation (you are making an assertion about something). What you are currently saying with your condition is: the text node of ns1:some-element MUST have a value of 'false' AND ns1:some-other-element MUST exist. Anything else is an error.

The condition you are probably looking for is

<iso:assert test="ns1:some-element = 'false' and /ns1:same-other-element or ns1:some-element != 'false'">Error message</iso:assert>

This condition will be true whenever ns1:some-element has a value that is not 'false', regardless of whether ns1:some-other-element is present.