Implementing Half Floats in D

[bearophile]

Walter Bright:

> http://www.drdobbs.com/cpp/implementing-half-floats-in-d/240146674

 From the article:

>Built-in types tend to run faster because the optimizer can take 
>advantage of mathematical identities,<

Generally in D we like the compiler to verify user-applied 
annotations like pure and const. For the compiler of a normal 
language today it's probably too much difficult to prove the 
theorems coming from those identities on user defined types. But 
if the compiler assumes the programmer to be right on this 
(because such types are usually defined in well reviewed 
libraries), then I think it's not too much hard to invent a small 
set of @annotations that attached to a user defined struct tell 
the compiler to allow some optimizations typical of integral 
numbers, floating point numbers, complex numbers, gaussian 
integers, quaternions, octonions and few others, according to 
them having associative, commutative, etc, properties, or not 
having them.

Bye,
bearophile