disabling unary "-" for unsigned types

[Igor Lesik]

>The problem I see with D is that Walter has mostly experience with C/C++. 
>The features inherited from those languages tend to work much better in D.
Is it really the problem? I think the original idea was to have better alternative
to C/C++, and D 2.0 looks good in that respect; and D has good chance
to be welcomed by C/C++ folks since (almost) no learning is required.

The "ambitious" features of D sometimes do not look well polished, (I could be wrong),
and other than the talks at Google I could not find any material about
advanced features, directions and design principles (will really
appreciate if someone can give me pointers to such materials, if it exists).

I hope TDPL book will cover D's design principles and (if it makes sense) may be compare
D'd advanced/ambitious features to other languages/approaches.
I like the concurrency chapter, it is great that memory model is discussed and
comparison with other languages is presented.