sumtype 0.3.0

[jmh530]

On Wednesday, 9 May 2018 at 14:56:20 UTC, Paul Backus wrote:
> [snip]
>
> What length actually does, after all the compile-time stuff is 
> expanded, is essentially this:
>
> switch(v.tag)
> {
>     case 0: return sqrt(v.value!Rectangular.x**2 + 
> v.value!Rectangular.y**2);
>     case 1: return v.value!Polar.r;
> }
>
> It's the same thing you'd get if you were implementing a tagged 
> union by hand in C.
>
> It's not exactly the same as a function specialized for 
> Rectangular, because the entire point of a sum type or tagged 
> union is to allow runtime dispatch based on the tag. However, 
> the process of choosing which function goes with which tag 
> takes place entirely at compile time.

Thanks. That makes sense.