xpath support

[mchlrch]

• XPath functions for where it's needed (split-equivalent)
• XPath completion when possible (create an index of all paths)

Goal: A standalone CLI tool that reads out XML paths, generates the appropriate EMF object model for a LogicalSource and then serializes into DSL text.

xrm-cli -extract-sources -xml foobar.xml > foobar-sources.xrm

[mchlrch]

Here's one approach for implementing this functionality:

1. Inspect XML to get inventory of paths, include the path inventory in XmlLogicalSource (build AST and serialize DSL file). I haven't done much with XPath so far, so I don't know, if the paths will be
   Sprachzonen/Sprachzone[attribute::Sprache='DE']/Synonym[attribute::Nr='1']/Definition[./Typ='ab']/Text or only
   Sprachzonen/Sprachzone/Synonym/Definition/Text

2. Implement proposal provider for Referenceable.value. Create proposals based on the path inventory.

3. Add validation rule that checks Referenceable.value to be valid XPath

[mchlrch]

2. Implement proposal provider for Referenceable.value. Create proposals based on the path inventory.

It makes sense to first play with the proposal provider and check if that approach is workable, before implementing the other parts