A guide on using the Zephyr ASDL language (my implementation, specifically) | The Abstract Syntax Description Language (gist.github.com)
from ChubakPDP11@programming.dev to programming@programming.dev on 07 Apr 2024 21:38
https://programming.dev/post/12493097

I wrote a short tutorial on using my implementation of ASDL. You can find link to it in the document.

I don’t have a blog or things like that so I just used a Github Gist.

For some reason I got locked out of my Github account and if it was not for a miracle I would have been locked out forever. I barely use Github anyways. I don’t understand why Tarvolds uses this shit corporate hellhole of a website as the primary platform for his projects, which sadly includes Git.

I made a model in ChatGPT to walk me through libgit2 so I can make my own remote host. I don’t like any of the other bloated Git on Web platforms that are out there. I know about Git Tea, but that damn thing is bloated. I want some thing like this guy has: c9x.me

This is what I mean when I say ‘OWN YOUR DATA’. Don’t trust Github, or any of these corporations, with shit.

I get this is really hypocritical to use Gist, then turn around and call Github a soulless corporation. But sadly, I use it BECAUSE it’s a soulless corporation, not in spite of it.

I don’t have money to buy a server. Yes, I am that poor. That is why I have to trust this PaaS and SaaS assholes.

Anyways fuck Github.

#programming

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Corbin@programming.dev on 07 Apr 2024 22:06 collapse

Congratulations on taking a step towards self-hosting and meta-circular compilation. ASDL is a great intermediate meta-language and it can be used to abstract any sort of Builder or Command workflow. This is sometimes called a “narrow waist”; ASDL replaces ad-hoc AST-builder objects with a unified protocol and interface.

For example, I encoded Monte into ASDL while rewriting the compiler in Monte, as part of a self-hosting effort. I also wrote a module which parses ASDL and emits Monte modules, including AST-building tools at runtime. Monte supports E-style quasiliterals, including source-code literals. This let our compiler directly consume ASDL files and emit Monte source code. Going beyond the compiler, this allowed me to encode UI elements and widgets as ASTs and use the Command pattern to write widget-handling objects.

ChubakPDP11@programming.dev on 07 Apr 2024 23:19 collapse

Thanks a lot my good man. Is this Monte? github.com/monte-language/monte I can’t find the source code?

Can you tell me what you think of the code my implementation emits when you got the time? Is it good, bad, medicore etc?

So when you’re building a language, should you always use a builder for the AST specifications? Becuase I figure, you don’t need that in a language like Haskell or OCaml right?

I currently have 3 projects I ping-pong.

1- Marsh, a POSIX shell in C; 2- Awk2X; a translator of AWK to several languages, like C, Python Rust etc. This one is in Haskell 3- Cephyr; a C compiler in OCaml

For Marsh, I am stuck in the job control section. I just can’t seem to find a flow for redirecting input and output. I think I am striking a balance though. I revised the job control like 10 times, literally 10 times.

But for Awk2X and Cephyr, I am kinda stuck at defining the AST. I learned Haskell just last night and I made this AST. I am not ‘stuck’ really, I will move on from it soon.

data UnaryOp
  = Prefix PrefixOp
  | Postfix PostfixOp
  deriving (Show)

data PrefixOp
  = PrefixIncr
  | PrefixDecr
  | Plus
  | Minus
  | Not
  deriving (Show)

data PostfixOp
  = PostfixIncr
  | PostfixDecr
  deriving (Show)

data BinaryOp
  = Add
  | Sub
  | Mul
  | Div
  | Mod
  | Eq
  | Ne
  | Gt
  | Ge
  | Le
  |
Corbin@programming.dev on 08 Apr 2024 23:48 collapse

Your code looked alright. Working in C is a risky chore. You’re early in your journey and I think it’s good to get a taste of many of the traditional techniques before turning towards newer fancier algorithms.

“Haskell and OCaml”, hm? The two concepts you need to internalize are katamorphisms and paramorphisms. You may have heard of “recursion schemes”; these two schemes are the ones available on any tree. Fundamentally, most of a compiler is tree-to-tree transformations (nanopasses), and they are expressible as one of two forms:

  • Katamorphism: The leaves of each node are transformed before the branch (bottom-up)
  • Paramorphism: The leaves are transformed after/during the branch transformation (top-down)

If you look again at my AST builder builder, you’ll see .run() and .walk() methods, implementing the recursion for any katamorphism or paramorphism respectively. In Haskell, these are called Traversable types. This is a pun in Monte, where .run() is also the default method; the syntax makes it easy to perform a katamorphism by passing a tree-traversing object directly to the AST.

Your types are alright, but you’ll want to pass a generic parameter through them, turning them into a valid Functor in Haskell or a generic module in OCaml. This is a basic defense against the “AST Decoration Problem”, AKA the “AST Typing Problem”. As you add features to your compiler, you’ll realize why these are necessary.

ChubakPDP11@programming.dev on 10 Apr 2024 18:37 collapse

(Sorry if this is a double post) I think what you call ‘decoration’ I call 'augmentation;. After many iterations ,I came up with this AST: pastebin.com/NA1DhZF2

I like it, but I am still skeptical as of comitting to it. I really want to use Functors… But i’m nto sure how. These are new concepts to me!