Talk about stuff that's hard to do or impossible in C++ (or just a PITA
like the whole language) and compare it to some nifty D code.
For example template metaprogramming. No easy way to do template
constraints, no is expressions nor a proper typeof so you have to use
specialization a lot.
You could also show something that checks for an "interface" at
compile-time, like
template isInputRange(R)
{
enum bool isInputRange = is(typeof(
{
R r; // can define a range object
if (r.empty) {} // can test for empty
r.popFront(); // can invoke popFront()
auto h = r.front; // can get the front of the range
}()));
}
CTFE is another strong feature.
You could for example show some code that generates Token handling code
(an enum for the tokens, associative arrays for token 2 string and the
other way around, etc.) to be used by a lexer without the necessity for a
DSL like in Clang or a separate tool like dmd.
