peridot VS metalang99

I've mostly finished up a preprint of a research paper on Peridot, my programming language! It still needs some work, but I'm happy enough with it to post it. If you have any questions or suggestions don't hesitate to tell me here. I would love feedback :-)

I'm finishing up with Peridot! The research goals of the project are close to being accomplished, so I'll be wrapping up soon. I'm really satisfied with it as a proof-of-concept for the ideas it implements. The last main bit of the project is a research paper I'm writing which details the language and its applications in detail.

Hey all! I've been working on my programming language Peridot for about six months, and it's finally at the point where I can call it an MVP! Peridot is a language in which the compiler backend is implemented in userspace via metaprogramming.

The Peridot MVP is feature-complete! All that's left to do are bugfixes, after which it will be a real, usable language. Here's the major features, in no particular order:

I'm not aware of any current implementations, but I'll be implementing it in my language, Peridot. Unfortunately that won't be for a few months though.

The second was called Konna. AFAIK it’s Finnish for “frog”, but sources seem to disagree? I don’t speak Finnish, I got the word from a Finnish video game. My third and current language is called Peridot. I’m pretty proud of this name, although it’s less searchable than the previous ones. The origin is pretty simple, I was just looking around at gemstones and thought peridot looked neat.

Hey! I'm Peridot's author. Peridot is a language based on two-level type theory which allows for the compiler backend to be written in userspace. The language is really two languages tied together: a logic language, and a dependently typed functional language. The former is built for metaprogramming - high-level optimizers and compilers can be written that translate the latter language into a target language of choice. An in-depth explanation of the language's rationale can be found here.

There are also other approaches. Macro variants making use of `__VA_ARGS__` would be probably the best trade-off. If you want a slightly more ergonomic syntax, something like Metalang99 [1] will help (and the author even wrote a post about this exact subject [2]). Codegen is another option which may work better than other options depending on the situation and exact implementation strategy. And there is always the Reflection TS [3], which may or may not be incorporated to C++26...

[1] https://github.com/Hirrolot/metalang99

[2] https://hirrolot.github.io/posts/pretty-printable-enumeratio...

[3] https://en.cppreference.com/w/cpp/experimental/reflect

I went down the rabbit hole with C99 metaprogramming after reading through the list. For reference: https://metalang99.readthedocs.io/en/latest/, https://github.com/Hirrolot/metalang99

Honestly I have to disagree. There is nothing particularly special about what Super Template Tetris(STT) is doing.

At its core, template metaprogramming is just functional programming at compile time. STT is just a template and a runtime function which do the following:

1, take an input via compile time flag (the `-D DIRECTION`)

2. take a type input from an included header file containing the current state (`#include "current_game.h"`)

3. via functional programming, compute the results of a single step of the game.

4. specialise a single function using the results of step 3. this function prints the computed result to the screen and the computed game state to a file (`./current_game.h`).

5. gcc/clang exits. compilation is complete.

6. call the compiled binary.

7. the binary runs the specialised function and prints the outputs.

Sure it's fucky and you shouldn't do that in production but what sane individual is writing a piece of code that at runtime (after compiling) seeks out one of its own source files and modifies that file?

To prevent this from being possible you'd have to remove runtime file IO from the language. The other potential solutions wouldn't work:

1. Remove templates entirely: Still would be possible using https://github.com/Hirrolot/metalang99 which solely uses the preprocessor. Given that the pre-processor is literally just term substitution(a glorified copy/paste engine), if you removed that as well, you'd have to accept no form of metaprogramming at all.

2. Remove the ability to #include other files: Could still be done by doing everything inline. `#include` is just copy-paste anyways so it's more an abstraction than anything else to the compiler and preprocessor, it's basically the same as if all the code was pasted into the same file.

That leaves you with removing file IO. Without IO a programming language is basically useless, particularly as a systems programming language.

P.S. I wrote Metalang99 BTW.

Metalang99, a metalanguage for C99. Simple :)

Just wait until you see some other things by the same author, like https://github.com/Hirrolot/metalang99

I did get a few great responses there as well, though. One was a link to this impressive piece of work: https://github.com/Hirrolot/metalang99/blob/master/examples/lambda_calculus.c

Some preprocessor nonsense: https://github.com/Hirrolot/metalang99/blob/master/examples/lambda_calculus.c