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All this pain over something so small...

Epoch language design
4: Adsense

My mid-term goal for the Epoch language project remains the same: I want to get Era back up to speed and start developing a better IDE now that the compiler is more or less solid.

However, the short-term implication of this is that I need support for GUI apps in the compiler, and that means resources. The last couple of days have been eaten up by trying to get basic resource compilation support working so that I can do things like embed dialogs, menus, and icons in .EXE files.

This is more of a pain in the ass than it sounds.

Windows (and, apparently, most third-party resource editors) is extremely picky about the format of resources in an .EXE. Misalign one byte, or shuffle a pair of offsets, or write things in the wrong order and it will refuse to acknowledge that your resources exist.

(Funny story: I spent about an hour and a half just now trying to figure out why I could see embedded icons in my resource editing apps, but Explorer insisted that the .EXE contained no icons. Turns out I had two things in the "wrong" order in the resource table. Swapping them around caused everything to start working as expected, even though the data was totally sensible with the first ordering.)

I think I've downloaded every PE dissection utility ever written; some are useful, some are not, and many are useful for one specific thing and useless for everything else. At one point I almost broke down and just wrote my own so I could get all the features I wanted under the same roof, but that would have served only as an even bigger distraction, so I resisted the urge.

To give you an idea of how frustratingly nitpicky this stuff is, consider the fact that I already have a working set of code for doing resource compilation and embedding, written in C++. I wasn't hacking this out from scratch - this was just attempting to port existing code into Epoch. Despite my best attempts at faithfully reproducing the C++ compiler's behavior in the Epoch compiler, it took quite a few false starts to reach a point where the damned thing works.

At long last, I have basic resource compiling done... for icons. The next step is to add all the other resources that Era needs: accelerators, menus, manifests, and possibly also dialogs. Thankfully most of the finicky junk is taken care of, and adding new resource types is primarily a matter of making sure the individual resources' data gets written correctly.

On a totally unrelated note, I've done some thinking, and I'm pretty sure I know how I want to approach cleaning up the Epoch type system. Rather than making everything value-semantics by default, with opt-in for reference semantics, I'm going to go the opposite direction. Everything has reference semantics by default unless you specifically opt-out.

Opting out has two basic use cases: flattening structures to remove indirections, and allocating data on the stack instead of the free-store. Structure flattening is all about locality of reference, and stack allocation is all about speed. I'm pondering how to have these two situations interact with garbage collection, but I need to figure out how to opt out of garbage collection in a general way anyways, so they might end up getting intertwined a bit.

For now, though, I think it is time to relax.

Jan 09 2014 08:53 AM

Any particular reason you are mucking with Windows resources, rather than integrating with a cross-platform windowing library (i.e. something like QT)? It seems a serious barrier to language adoption in this day and age, to have a Window-only IDE.

Jan 09 2014 01:02 PM
Reasonable question!

There are two motivations at play here. The big one is that I want to develop UI implementation techniques that are uniquely suited to my language, rather than trying to shoehorn something like Qt into a totally alien object model and development paradigm. I honestly feel like using libraries designed for other languages is a massively bad move, not just because it results in lower-quality code, but because it sends the message that the language is not self-sufficient. This strikes me as a major negative.

The second motivation is that I want to have full first-class support for any OS that Epoch runs on. Right now that's only Windows, for numerous reasons. Embedding resources is a crucial feature for developing respectable Windows apps, and not just for UI reasons - think e.g. manifests, which are important for security permissions and other paraphernalia on Windows.

As a bonus, having support in the compiler for embedding resources means I don't implicitly tie every other user of the language to my choice of UI kit. If someone else feels differently and would rather use Foo Kit instead, they're perfectly free to do so. By contrast, if the flagship software written in the language ties to a specific UI framework, the odds of first-class support for anything *else* drops dramatically.

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