Error Handling
- Invalid expression syntax.
 - Valid operators for given datatypes.
 - Multiple subcase/result with non-existing results:
- Unique aliases for all subcases combined, the expression shows whatever the alias represents.
 - If a particular subcase doesn’t have a datatype, the expression still shows that, however a contour is n/a when applied.
 
 - Import/export of expressions.
 - Chaining data types.