armchair_progamer

I wanted to make a programming language that resembled magical circles. This is more like a way to write PostScript that looks like a magical circle, but I will refer to it as Mystical in this document.

Related: https://programming.dev/post/28438809

Rivulet is a programming language of flowing strands, written in semigraphic characters. A strand is not pictographic: its flow does not simulate computation. There are four kinds of strands, each with their own symbolism and grammatical rules. Together, they form glyphs, tightly-packed blocks of code whose strands execute together.

Here is a complete Fibonacci program:

   ╵──╮───╮╭─    ╵╵╭────────╮
    ╰─╯╰──╯│       ╰─╶ ╶╮╶╮╶╯
   ╰─────╮ │      ╭─────╯ ╰─────╮
         ╰─╯ ╷    ╰───       ───╯╷

   ╵╵─╮  ╭─╮     ╭──       ╵╵╰─╮  ──╮──╮
      ╰─╮│ ╰─╯ ╵╵╰─╯╶╮       ╴─╯  ╭─╯╭─╯
      ╰─╯╰─ ╰──╯╰────╯       ╭╴ ╵╶╯ ╶╯╶╮
        ╭─╮ ╭╴               │  ╰──────╯
        │ │ │                ╰─╮       ╭─╮
      │ │ ╰─╯                  │     │   │
      ╰─╯            ╷         ╰──── ╰───╯╷

   ╵╵ ╭──  ──╮  ╭─╮         ╵╰─╮
      ╰─╮  ╭─╯╭─╯ │          ╴─╯
       ╶╯╵╶╯  │ ╷╶╯          ╭─╮
     ╭─╮ ╰────╯ │   ╭─╮        │
     │ ╰────╮ ╭─╯ ╭╴│ │      ╭─╯
     ╰────╮ │ │ │ │ │ │      │
     ╭────╯ │ │ ╰─╯ │ ╷      ╰─╷
     ╰────╮ │ ╰─────╯ │
          │ ╰─────────╯╷

Target audience: Practitioners interested in programming language design and familiar with representations of errors in at least a few different languages such as error codes, checked/unchecked exceptions, tagged unions, polymorphic variants etc.

Estimated reading time: 60 to 90 mins.

Neut is a functional programming language with static memory management.

Its key features include:

• Full λ-calculus support
• Predictable automatic memory management
• The absence of annotations to the type system when achieving both of the above

Neut doesn't use GCs or regions. Instead, it takes a type-directed approach to handle resources.

A ~1 month old post about (sort-of) real-world experience from someone whose worked on a language as a hobby for 3 years.

The interesting part starts at https://vine.dev/docs/features/inverse

Discussion: https://news.ycombinator.com/item?id=43144040

After three years I feel like I'm qualified to give some general advice.

It will take much longer than you expect

Arenas, a.k.a. regions, are everywhere in modern language implementations. One form of arenas is both super simple and surprisingly effective for compilers and compiler-like things. Maybe because of its simplicity, I haven’t seen the basic technique in many compiler courses—or anywhere else in a CS curriculum for that matter. This post is an introduction to the idea and its many virtues.

Background: the authors are developing a static analysis library (or perhaps framework) called Codex and publishing papers on it. This post summarizes their most recent paper, which got accepted to OOPSLA 2024. The full paper and an artifact (Docker container) are both linked, and Codex is on GitHub with a demo.

Excerpt:

One of the main challenges when analyzing C programs is the representation of the memory. The paper proposes a type system, inspired by that of C, as the basis for this abstraction. While initial versions of this type system have been proposed in VMCAI'22 and used in RTAS'21, this paper extends it significantly with new features like support for union, parameterized, and existential types. The paper shows how to combine all these features to encode many complex low-level idioms, such as flexible array members or discriminated unions using a memory tag or bit-stealing. This makes it possible to apply Codex to challenging case studies, such as the unmodified Olden benchmark, or parts of OS kernels or the Emacs Lisp runtime.

The language itself: https://crystal-lang.org/. Crystal is heavily inspired by Ruby but with static typing and native compilation (via LLVM). To make up for not being dynamic like Ruby, it has powerful global type inference, meaning you're almost never required to explicitly specify types. The linked "Notes on..." page gives much more details.

Abstract:

A computer program describes not only the basic computations to be performed on input data, but also in which order and under which conditions to perform these computations. To express this sequencing of computations, programming language provide mechanisms called control structures. Since the "goto" jumps of early programming languages, many control structures have been deployed: conditionals, loops, procedures and functions, exceptions, iterators, coroutines, continuations… After an overview of these classic control structures and their historical context, the course develops a more modern approach of control viewed as an object that programs can manipulate, enabling programmers to define their own control structures. Started in the last century by early work on continuations and the associated control operators, this approach was recently renewed through the theory of algebraic effects and its applications to user-defined effects and effect handlers in languages such as OCaml 5.