support for various angular units in std.math

[Andrei Alexandrescu]

On 2/28/11 12:49 AM, Walter Bright wrote:
> Colin Wallace wrote:
>> When using trigonometric functions, they all deal with radians. So
>> I've been having to do lots of converting. Converting is very
>> straightforward, but I still think it would be nice if there were some
>> built in functions for dealing with other units than radians. I think
>> a system that looked like what is used for the Duration struct in
>> core.time would make things more readable. The code for taking the
>> sine of a number measured in degrees could look like:
>> sin!"degrees"(45)
>> rather than
>> sin(45*PI/180)
>
> I appreciate the suggestion, but suspect that adding a parallel set of
> trig functions that do nothing more than multiply the arg by a constant
> is more cognitive load for the user than benefit.

Agreed. What would add value is a units library that refuses calls to 
e.g. trig functions unless the user specifically inserts a conversion. 
That is, instead of

sin!"degrees"(x);

you'd use:

sin(to!"degrees"(x));

That way the conversion remains explicit but is hoisted out of the 
multitude of math functions.


Andrei