Support strings in expressions, to allow queryRel & friends to communicate in 1.13+ blocks. Will probably be limited to basic string addition and passing in to methods, no replacement / indexing / etc. utilities.

This is informally known as "Expressions Part III: The Search for More Expressions".

Catch the other movies on DVD and Blu-Ray:
"Expressions Part I: Dr. ANTLR or: How I Learned to Stop Worrying and Love the Parser"
"Expressions Part 2: Express Harder"