When using to_json(...) marshal expr.Type into string will get empty
object {} if this Type doesn't implement marshal method. So UntypedValue
obj before json.Marshal if this obj isn't json.Marshaler.
- Adds/Refactors methods for Set, Merge, Filter, Delete
- Renames expr/Vars.Merge to MustMerge, updates its usage
- Appends kvFunctions to parser in pkg/expr
- Update/Fixes tests and example testable