The common C way to get a blob of generic data at runtime is to use void pointers like so:

struct Structo {
  int type;
  void* data;
}

Then cast the void pointer to whatever data you needed based on the type. I imagine D has a better mechanism for this sort of thing, but after some searching I couldn't find what is considered "best practice" for this application.

The obvious solution is to use objects and have polymorphism solve the problem, but if you want to avoid as much memory dereferencing as possible (say, to avoid cache misses), objects seem a poor choice since they are always reference variables.

So what's considered the best alternative to void pointers in D if you don't want to use objects? Make a tagged Union of all possible datatypes in the struct? Have a Byte array and cast that instead of a void pointer? Some sort of magic involving templates or other metaprogramming mechanisms?

On Tuesday, 30 January 2018 at 17:41:53 UTC, jsako wrote:
> So what's considered the best alternative to void pointers in D if you don't want to use objects? Make a tagged Union of all possible datatypes in the struct? Have a Byte array and cast that instead of a void pointer? Some sort of magic involving templates or other metaprogramming mechanisms?

https://dlang.org/phobos/std_variant.html

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  Simen