disabling unary "-" for unsigned types

[Walter Bright]

Andrei Alexandrescu wrote:
> Walter Bright wrote:
>> Lutger wrote:
>>> It's a valid viewpoint, but it is a 'should'. I believe many 
>>> programmers have only passing familiarity if at all with the 
>>> semantics of unsigned types and floating point operations. At least 
>>> when coding, they don't have these semantics in mind. Why do you 
>>> think Java doesn't have unsigned types? 
>>
>> Naive programmers have trouble with Java floating point as well:
>>
>>     http://www.eecs.berkeley.edu/~wkahan/JAVAhurt.pdf
>>
>> There's just no getting around it. Should Java just remove floating 
>> point types as well?
>>
>> Heck, I knew a degree'd mechanical engineer who could not understand 
>> why his calculator kept giving him answers off by a factor of 2 (he 
>> refused to understand roundoff error, no matter how many times I tried 
>> to explain it to him - he believed that calculators had mathematically 
>> perfect arithmetic).
> 
> How could he refuse?

Beats me. Naturally, I lost all respect for his engineering prowess.

> One of my favorite games with calculators was to 
> successively extract square root of 2 until I got 1. The better the 
> calculator, the more steps it takes. That's kind of difficult to refuse 
> to acknowledge :o).
> 
> Andrei