Re: Num class

Marcin 'Qrczak' Kowalczyk writes:

Thu, 19 Oct 2000 16:25:02 +1300 (NZDT), Tom Pledger pisze:

...

A language extension for subtyping would be of some use there. For example, if Int is set up as a subtype of Integer, meaning that an Int value is acceptable anywhere an Integer value is expected (with the typechecker inserting the conversion code), the literal 42 can unambiguously be assigned the type Int.

This disallows literals of a non-standard type Int8. Not good.

If you had such a non-standard type, I imagine you'd also declare something like this: instance Subtype Int8 Int16 where ... instance Subtype Int16 Int24 where ... instance Subtype Int24 Int where ... and hence literals in the range -128 to 127 would be typed Int8, etc. Regards, Tom