15.7 Summary

This chapter has highlighted a sample of extensions offered by Xalan, Saxon, and EXSLT. You learned how to use several extensions (including an extension attribute and extension element) and several extension functions. You also learned how to use the fallback element, along with informative messages, which responds as directed if a processor does not support a given extension element. You can also test for extension functions and elements using the function-available( ) and element-available( ) functions from XSLT.

This chapter did not explore how to write your own extensions, but that's because it is beyond the scope for an introductory text and is somewhat different for every processor. Chapter 8 in Doug Tidwell's XSLT (O'Reilly) provides some guidance on writing extensions if you are interested in learning how to do this.

The next chapter presents a brief introduction to XSLT 2.0 and XPath 2.0.