[addaon]

I think a challenge to me for typing assembly, unless you’re doing old-school C style minimally-useful types, is that assembly types tend to be both more ad hoc and more transient than types in higher level languages, because these types come from the intersection of the problem domain and the way of expressing the solution, instead of just from the problem domain. In C++ I might have a type for “aircraft velocity in mm/s”, but in assembly I might have that type on one line, and then go to velocity in 2x mm/s the next line to save a renormalization; or have types for various state flags, but have them pack differently into a word in different places in the code. This is all expressible, but I think it would make me favor a more implicit typing with a heavier emphasis on deduction, just to minimize the description of types that exist but are not in themselves interesting.

[noduerme]

Just thinking about an aircraft's velocity as a specific type, rather than a vector with three floats, has my mind whirling. I can imagine a lot of terrifying things I wish I didn't think could be added later to that struct in some avionics system. What would you need a type for that for? Am I thinking too high level, where this type might include its own getters and function calls?

[laszlokorte]

Think of types more as physical units to check your calculation. The position on a chess board and on a checker board are both 2d integer vectors but you might or might not want them able to be summed together, the same way that 5 liters and 5 grams are both real numbers but should not be summed.

[addaon]

See the other replies — think physical units. An aircraft velocity is a three-vector, but not all three vectors are aircraft velocity. There are probably many different aircraft velocity types, but taking a typical one (NED alignment, mm/s scaling, some particular precision), the type is the set of three vectors that can, for example, be meaningfully added to each other. It makes sense to add two aircraft velocities; it does not make sense to add an aircraft velocity and a pixel color (another three vector), so they are observably different types.