Implement Column Intersection Type (part 1)

[jdunkerley]

A Column can be it's single value if and only if it is a single row column.

• Based on the value_type and length
• Should also check that single value is Not Nothing.
• Want Column.from_java_column to return the Intersected type.

e.g. Single Row Int64 Column should be: Column & Integer

Needs to attach the conversion logic so x:Integer works if and only if as above.
Should do this for Integer, Float, Decimal, Text, Date, Date_Time, Time_Of_Day.

To test the following:

• All column functions still work.
• Table functions all work unchanged
• Convertible to its value type explicitly, and then able to call the functions and get correct result.
• Want to test calling functions taking the value type without conversion, with the auto convert should step in,

x val:Integer = ...

y = Column.from_vector "Test" [1]
z = x y

If the last one is a problem, we should discuss what to do. Could be that the GUI adds the extra conversion.
The user shouldn't need to know about it.

[enso-bot]

Radosław Waśko reports a new STANDUP for yesterday (2025-01-23):

Progress: Working on intersection type PR, trying to figure out the semantics and what is the desired approach and why it doesn't work. It should be finished by 2025-01-28.

Next Day: Next day I will be working on the same task. Continue.

[enso-bot]

Radosław Waśko reports a new STANDUP for the provided date (2025-01-24):

Progress: Adding many tests for intersection types semantics, created some tickets. It should be finished by 2025-01-28.

Next Day: Next day I will be working on the #12137 task. Get the first PR merged, work on single-column Table.