create useful feedback message if someone tries to load an xml document that declares an .xsd schema

[ilovan]

Example:
https://dev-cwrc-writer.cwrc.ca/?githubPath=XML%2FCareOfTheDead_chap1-revised.xml&githubRepo=ilovan%2FCiteLens-Documentation

Add something like:

Unable to read the schema declared in the document. Please make sure the uploaded document declares a compact RelaxNG schema. "

@ajmacdonald , is it correct that we can only handle compact syntax relaxNG?

[ajmacdonald]

Yes, currently only RelaxNG is supported

[ajmacdonald]

xsd schemas are associated with the document in a different way than RelaxNG. Is it worthwhile to check for them even if we don't support them, or is it enough to display the missing schema message?

[ilovan]

let's go with message for now - I can't think of any strong reason for checking for XSD schemas if we don't support them anyway.

[ajmacdonald]

cwrc/CWRC-WriterBase@db37358