Returns a diff of the current context document/version with another version of this document or another document.
<p:diff contentDiffType="text|html|htmlsource"> <p:otherDocument id="expr" branch="expr" language="expr" version="expr"/> </p:diff>
If no p:otherDocument element is specified, the diff will automatically be taken with the previous version of the document. If there is no such version (because the document has only one version yet), there will be no diff response.
If a p:otherDocument element is supplied, any combination of attributes is allowed, all attributes are optional.
The contentDiffType attribute is optional, text is the default. Specify 'html' for a visual HTML compare, 'htmlsource' does in an inline HTML source diff (rather than a line-based diff). This attribute only has effect on Daisy-HTML parts.
A diff-report element, except in the case no output is generated because the from or to version is not available.