How about supporting embedded/inline matcher in XMLUnit?

For example, suppose we have

Expected (control) XML '<elem1><elem11>${xml-unit.any-number}</elem11></elem1>'

Actual (test) XML #1 '<elem1><elem11>123</elem11></elem1>'

Actual (test) XML #2 '<elem1><elem11>abc</elem11></elem1>'

We consider actual XML #1 equal to the expected XML, but actual XML #2 not equal to the expected XML.

This is actually an idea from JsonUnit.

I feel this feature really useful and powerful, especially with the Custom matchers support.