Fully dynamic d by opDotExp overloading

[BCS]

Hello Christopher,

> 
> Testing the logic of your code will catch the latter error and not the
> former. But the former isn't an error, if it has the same result.
> 

IIRC dynamic language do gobs of TDD/unittests because they have no choice 
for just this reason. Any other approach and you have no clue what you'll 
get. Given a choice between an option that lets in static checking and one 
that forces the use of runtime testing/checking, I'll go for the static choice 
every time. (sorry if I'm getting OT)