Editor for teaching TEI - features

This is an attempt at listing the minimal set of features that a TEI editor used for teaching purposes should have.

1. Basic required features

1.1. multiplatform
1.2. validation with Relax NG based on the xml-model PI in the document
1.3. continuous validation
1.4. contextual suggestions (following the schema)
1.5. XSLT 2 transformation (Saxon HE? that would offer XQuery as well)
1.6. easy to use
1.7. free for students
1.8. syntax highlighting for XML (that naturally includes XSLT)

Comments, justification, discussion

(please use the hard-set numbers; note that discussion is still running at TEI-L)

• Item 1.7. could imply a moderate licensing fee; we have to bear in mind that the entire discussion started because of a department refusing to pay high licensing fees for a semester course

2. Ideally...

2.1. free
2.2. XPath query
2.3. Inline documentation (i.e. the little pop-ups with the definition of the element)
2.4. pre-set templates (example?)
2.5. syntax highlighting for XQuery

3. Features that can be eliminated from a "teaching editor" in order to decrease its cost

3.1. No XSLT 3 (as a consequence of the fact that no commercial tool such as Saxon PE/EE could be used in such an editor)
3.2. No need for XSLT or XQuery debuggers
3.3. no need for database connectivity
3.4. no need for a built-in SVN (etc.) client
3.5. no need for a Tree Editor such as the one offered by oXygen
3.6. no need for Compare Files/Directories tools
3.7. no need for big-file editor or big-file support in general
3.8. no need for syntax highlighting and editing support for some file types which are not XML-based (JavaScript, CSS, JSON, etc.).

Notes

The impetus for establishing the above came from a sub-thread on the TEI-L list bulleted by the following messages: [1], [2], [3]. The idea is to see whether the community can agree on a single feature set that a dumbed-down commercial editor can implement is a "student version" with an appropriate license. Or, as Martin Holmes puts it, we want to "arrive at something which would be utterly useless for the likes of me, and quite frustrating for serious users, but perfectly functional for teaching introductory XML encoding classes over a few months."