[WalterBright]

Interesting you brought that up. I implemented them for Symantec C and C++ back in the 90s.

I never want to do that again!

They are brittle and a maintenance nightmare. They did speed up compilations, though, but did not provide any semantic advantage.

With D I focused on fast compilation so much that precompiled headers didn't offer enough speedup to make them worth the agony.

[fuhsnn]

>They are brittle and a maintenance nightmare

I happened to be reading DMC source this week, those hydrate/dehydrate stuff really is everywhere (which I assume is solely used for precompiled headers?)

[WalterBright]

Yup. I spent a crazy amount of time debugging that. The tiniest mistake was a big problem to find.