datatype99 VS llvm-cbe

Sum types and pattern matching have already been hacked together in a preprocessor macro in C; see https://github.com/Hirrolot/datatype99.

It does not. There are people who have implemented such constructs in C code however, for example: https://github.com/Hirrolot/datatype99

Nice reference but with some strange bits:

> Algebraic data types are usually represented using a heap. Because of their non-uniformity, algebraic data types are more difficult to scan.

Using a heap??? We can represent ADTs using stack as well, that's what we usually do in C and Rust.

Shameless plug: https://github.com/Hirrolot/datatype99 (a library of mine that generates type-safe ADTs for pure C99).

I agree; I would especially not recommend abusing macros throughout an application codebase too much. Conceptually, Metalang99 is more of a (sub)language than a library, which also adds some entry barrier. Ideally, I see the application of Metalang99 being used "behind the scenes", e.g., encapsulated in separate code files/libraries such as Datatype99 and Interface99. This is what I (mostly) do in SmolRTSP.

I've done something similar with Datatype99 and Interface99. They are like a macro eDSL that compiles to C. The first one features algebraic data types, the second one features interfaces.

If you need a bit more high-level constructions, you can use the Datatype99 and Interface99 libraries. The former provides polymorphism over data, the latter -- over behaviour (I am the creator of these libraries).

OP, you might find datatype99 and its sibling projects interesting, though they mostly leverage the C preprocessor without going all the way towards defining a new language.

You can use Datatype99 to represent your AST tagged union conveniently.

Compared to plain C, you have ADTs which help from day to day programming. You can bring them to C (https://github.com/Hirrolot/datatype99) but I don't know if the Linux guys would allow it.

So how does the LLVM C backend work then?

https://github.com/JuliaHubOSS/llvm-cbe

One alternative worth mentioning, though, would be the LLVM C Backend maintained by the Julia community.

If you drop "easily" and "human" (/s) from your requirements list, then the C backend for LLVM might work. Then you can choose any programming language you want that has LLVM 10-compatible frontend.

If you really must have something that compiles in C (e.g. for a platform where you only have a C compiler) there's an LLVM backend that outputs C code: https://github.com/JuliaComputingOSS/llvm-cbe

You can convert llvm bitcode to C and then use C compiler, there is such project https://github.com/JuliaComputingOSS/llvm-cbe .

I'm really surprised that the LLVM C backends have continually been resurrected then abandoned over the years. It's a good solution to this sort of thing and would enable a lot of cool stuff like Rust to weird embedded platforms. The most recent one is the Julia backend: https://github.com/JuliaComputingOSS/llvm-cbe

Check this project out: https://github.com/JuliaComputingOSS/llvm-cbe.

Well IMO it can definitely be rewritten in Julia, and to an easier degree than python since Julia allows hooking into the compiler pipeline at many areas of the stack. It's lispy an built from the ground up for codegen, with libraries like (https://github.com/JuliaSymbolics/Metatheory.jl) that provide high level pattern matching with e-graphs. The question is whether it's worth your time to learn Julia to do so.

You could also do it at the LLVM level: https://github.com/JuliaComputingOSS/llvm-cbe

For interesting takes on that, you can see https://github.com/JuliaLinearAlgebra/Octavian.jl which relies on loopvectorization.jl to do transforms on Julia AST beyond what LLVM does. Because of that, Octavian.jl beats openblas on many linalg benchmarks

You can try your luck with the "resurrected" C backend: https://github.com/JuliaComputingOSS/llvm-cbe

I don't understand why I see so many requests for LLVM-based languages to change around their backend or IR, that seems to be a huge amount of work for comparatively little benefit. The correct thing to do there is to just add support for those to LLVM.