CODEWITHSUNDEEP
templatesinterfaceimplementationd
Paul Manta
Paul Manta

Reputation: 31567

Does D allow separation of interface from implementation in templates?

I haven't tried D yet, but it seems like a very interesting language that has found some neat solutions to problems in C++. I'm curious, did it also make it possible to separate interface from implementation in templates? If yes, then how?

Upvotes: 4

Views: 226

Answers (2)

BCS
BCS

Reputation: 78585

At some point in processing the use of a template, D needs all the information about the template. However, there is no reason that this information need be encode as the original source code (OTOH, as an implementation detail, all current D compiler do require that). This is a fundamental issue of any language that has templates stronger than generics. The implications of this depend on what you are trying to do.

If your interest in separation of interface and implementation is to hide the implementation (like shipping binary libraries and header files in C), then this can't be done. The closest you can get is some kind of code obfuscation system.

If, on the other hand, you are interested in avoiding the cost of reprocessing templates for each recompilation, something more general like a binary pre-compiled header format could allow the reuse of the results of the lexical, syntactic and some of the passes while compiling several other modules. In fact, that would be simpler to do with D than in C.

A third option would be link time code generation, but that has little difference from conventional linking with aggressive use of an anolog to pre-compiled headers.

Upvotes: 2

ratchet freak
ratchet freak

Reputation: 48196

no any templates used are fully expanded at compile time

this means that the compiler needs to know the full code of the template making it impossible to keep it out of the .di files

Upvotes: 7

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