Metaprogramming in D : Some Real-world Examples

[Don]

Christopher Wright wrote:
> grauzone wrote:
>> You're not testing for types, you're testing if it compiles. Inside 
>> the tested block of code, all sorts of things could go wrong. You 
>> can't know if is(typeof(...)) really did what you wanted, or if 
>> something broke.

You're testing, "is everything inside that OK?". If you want to know WHY 
it's wrong, you'd better make sure you're testing something simple.

> So it requires caution, and you want to keep the contents small. It's 
> useful, but it requires caution.

I don't even think it particularly requires caution. If it passes, you 
know everything is OK. It's just that it's an all-or-nothing test.

IMHO, one of the best features of it, is that you can have negative 
compile-time unit tests. You can create tests which must be rejected at 
compile time. I don't know of any other clean way to do that.