Konrad Hinsen
I am trying to write a larger piece of code using only type constraints for all the numbers, not specific types, in order to be able to choose the precision as late as possible.
Good for you! (I say this in all seriousness.)
This works rather well (something I can't say of many other languages), but one problem I keep running into is constants.
Something I need frequently is, for example, the Boltzman constant, 0.0083144708636327096 in my unit system. I can certainly type 0.0083144708636327096 everywhere in the code and make things work, literals have the nice property of being overloaded. But for the sake of readibility, I prefer to give this beast a name and have the explicit value only once in my code. So I create a module "Constants" with something like
k_B = 0.0083144708636327096
The trouble is that k_B then becomes "Double" by default
Right. The good old monomorphism rule, I assume. Query: does this rule ever make a programmer's job easier? Beats me.
(or any other type I declare it to be).
Right. But: you can declare it to have type Fractional alpha => alpha, which is the same type the constant has in the middle of an expression. <snip> Jon Cast