Agree. Typical FP with ADTs would lead to the same kind of data-driven style. The point at which he went too far for me is probably the struct layout optimisati

Agree. Typical FP with ADTs would lead to the same kind of data-driven style. The point at which he went too far for me is probably the struct layout optimisation (every shape has two defining numbers, it feels a bit restrictive). For me that’s the point where I’d check whether it’s really warranted and if so create new types to distinguish the original domain (Shape) vs. number crunching (ShapeDefinedByTwoNumbers - needs a better name).