alt Hacker NewsArguably, most of the metaprogramming in D is done with templates and it comes with all the flaws of templates in C++. The error messages are long and it's hard to decipher what exactly went wrong (static asserts help a lot for this, when they actually exist). IDE support is non-existent after a certain point because IDE can't reason about code that doesn't exist yet. And code gets less self-documenting because it's all Output(T,U) foo(T, U)(T t, U u) and even the official samples use auto everywhere because it's hard to get the actual output types.
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It is quite ridiculous to place C++ metaprogramming and D's. For one in D it's the same language and one can choose whether to execute compile time constant parts at compile time or run time. In C++ it's a completely different language that was bolted on. C++ did adopt compile time constant expressions from D though.
No, templates are only needed to introduce new symbols. And D templates are vastly superior to C++. D's superpowers are CTFE, static if, and static foreach.
auto is used as a return type because it's easy, and in some cases because the type is defined internally in the function and can't be named.
You would not like the code that uses auto everywhere if you had to type everything out, think range wrappers that are 5 levels deep.
I'd say D's template error messages are much better than C++'s, because D prints the instantiation stack with exact locations in the code and the whole message is just more concise. In C++, it just prints a bunch of gibberish, and you're basically left guessing.