Programming Languages

I wanted people to be able to try out my language online, and it’s now possible with a vscode like interface, sending code to a docker image running the interpreter!

It was easier than I thought to implement, and yes, security was a concern, but I have been able to harden the docker container as well as implement restrictions on the websocket server to avoid having users escaping the docker image and getting access to the VM it’s running on.

This pattern [(multi-stage programming)], which I'll refer to as "biphasic programming," is characterized by languages and frameworks that enable identical syntax to express computations executed in two distinct phases or environments while maintaining consistent behavior (i.e., semantics) across phases. These phases typically differ temporally (when they run), spatially (where they run), or both.

An older (2017) page on multi-stage programming

Winglang ("a programming language for the cloud"), the author's language

Abstract:

We present associated effects, a programming language feature that enables type classes to abstract over the effects of their function signatures, allowing each type class instance to specify its concrete effects.

Associated effects significantly increase the flexibility and expressive power of a programming language that combines a type and effect system with type classes. In particular, associated effects allow us to (i) abstract over total and partial functions, where partial functions may throw exceptions, (ii) abstract over immutable data structures and mutable data structures that have heap effects, and (iii) implement adaptors that combine type classes with algebraic effects.

We implement associated effects as an extension of the Flix programming language and refactor the Flix Standard Library to use associated effects, significantly increasing its flexibility and expressive power. Specifically, we add associated effects to 11 type classes, which enables us to add 28 new type class instances.

See also: the Flix programming language

Abstract:

The expression problem describes how most types can easily be extended with new ways to produce the type or new ways to consume the type, but not both. When abstract syntax trees are defined as an algebraic data type, for example, they can easily be extended with new consumers, such as print or eval, but adding a new constructor requires the modification of all existing pattern matches. The expression problem is one way to elucidate the difference between functional or data-oriented programs (easily extendable by new consumers) and object-oriented programs (easily extendable by new producers).

This difference between programs which are extensible by new producers or new consumers also exists for dependently typed programming, but with one core difference: Dependently-typed programming almost exclusively follows the functional programming model and not the object-oriented model, which leaves an interesting space in the programming language landscape unexplored.

In this paper, we explore the field of dependently-typed object-oriented programming by deriving it from first principles using the principle of duality. That is, we do not extend an existing object-oriented formalism with dependent types in an ad-hoc fashion, but instead start from a familiar data-oriented language and derive its dual fragment by the systematic use of defunctionalization and refunctionalization

Our central contribution is a dependently typed calculus which contains two dual language fragments. We provide type- and semantics-preserving transformations between these two language fragments: defunctionalization and refunctionalization. We have implemented this language and these transformations and use this implementation to explain the various ways in which constructions in dependently typed programming can be explained as special instances of the general phenomenon of duality.

Background:

Expression problem (wikipedia)

Defunctionalization (wikipedia)

Codata in action, or how to connect Functional Programming and Object Oriented Programming (Javier Casas)

Several months ago I gave a talk at work about Hindley-Milner type inference. When I agreed to give the talk I didn't know much about the subject, so I learned about it. And now I'm writing about it, based on the contents of my talk but more fleshed out and hopefully better explained.

I call this a reckless introduction, because my main source is wikipedia. A bunch of people on the internet have collectively attempted to synthesise a technical subject. I've read their synthesis, and now I'm trying to re-synthesise it, without particularly putting in the effort to check my own understanding. I'm not going to argue that this is a good idea. Let's just roll with it.

In this post, I will talk about the first version of the Intermediate Representation I designed for Kunai Static Analyzer, this is a dalvik analysis library that I wrote as a project for my PhD, also as a way of learning about the Dalvik file format and improving my programming skills.

Kunai source (Github)

Kunai paper

Shuriken (Kunai successor)

Dalvik is a discountinued VM for Android

Pre-Scheme is an interesting Scheme dialect which is being ported to modern systems. The language, why its being ported, and the porting effort are described in the linked post.

As described in the Pre-Scheme paper, the language offers a unique combination of features:

• Scheme syntax, with full support for macros, and a compatibility library to run Pre-Scheme code in a Scheme interpreter. The compiler is also implemented in Scheme, enabling both interactive development and compile-time evaluation.
• A static type system based on Hindley/Milner type reconstruction, as used in the ML family of languages (eg. Standard ML, OCaml, Haskell). Pre-Scheme supports parametric polymorphism, and has nascent support for algebraic data types and pattern matching, which are recently gaining popularity in mainstream languages.
• An optimizing compiler targeting C, allowing for efficient native code generation and portable low-level machine access. C remains the common interface language for operating system facilities, and compatibility at this level is essential for modern systems languages.

Due to the restrictions of static typing and the C runtime model, Pre-Scheme does not (currently) support many of Scheme's high-level features, such as garbage collection, universal tail-call optimization, heap-allocated runtime closures, first-class continuations, runtime type checks, heterogenous lists, and the full numeric tower. Even with these limitations, Pre-Scheme enables a programming style that is familiar to Scheme programmers and more expressive than writing directly in C.

Ironically, Pre-Scheme's original purpose was to implement the interpreter for another Scheme dialect, Scheme 48 (Wikipedia). But the lower-level Pre-Scheme is now getting its own attention, in part due to the popularity of Rust and Zig. Pre-Scheme has the portability and speed of C (or at least close to it), but like Rust and Haskell it also has a static type system with ADTs and parametric polymorphism; and being a LISP dialect, like most other dialects it has powerful meta-programming and a REPL.

GitHub

From README:

Lady Deirdre is a framework for incremental programming language compilers, interpreters, and source code analyzers.

This framework helps you develop a hybrid program that acts as a language compiler or interpreter and as a language server for a code editor's language extension. It offers the necessary components to create an in-memory representation of language files, including the source code, their lexis and syntax, and the semantic model of the entire codebase. These components are specifically designed to keep the in-memory representation in sync with file changes as the codebase continuously evolves in real time.

Key Features

• Parser Generator Using Macros.
• Hand-Written Parsers.
• Error Resilience.
• Semantics Analysis Framework.
• Incremental Compilation.
• Parallel Computations.
• Web-Assembly Compatibility.
• Source Code Formatters.
• Annotated Snippets.
• Self-Sufficient API.

Scrapscript is a small, pure, functional, content-addressable, network-first programming language.

fact 5
. fact =
  | 0 -> 1
  | n -> n * fact (n - 1)

My previous post introduced the language a bit and then talked about the interpreter that Chris and I built. This post is about the compiler that Chris and I built.

Design documentation: https://github.com/ZILtoid1991/pixelperfectengine/blob/master/docs/formats/m2.md

It has some weird solutions due to my limited experience with the subject and the target usage favor preallocation instead of live allocation. I took some inspirations from Music Macro Language, Assembly, and Lua. Due to the lack of a MIDI 2.0 format, I thought I'd come up with my own, adding capabilities to program adaptive soundtracks (emitting MIDI commands with calculated values, conditional emitting of MIDI commands, conditional looping and pattern playback, etc).

I initially gave it the name .m2 but while M.2 is an entirely different thing, an MML format by the name .m2 does exist on the PC98, thus I'm looking for some new name for mine. The only thing I can come up on the spot is MASM (or MIDI Assembly), but it's close to an already existing MASM (Microsoft Macro Assembler).

From the site:

We have entered a world in which we need to do more with less. If you, like us, have frowned at the difficulty and inefficiency of creating software, and wondered if there is a better way, Meta is for you. It is a descendant of the acclaimed REBOL and Logo computer languages. Logo was designed in academia to teach programming in a simple yet powerful way. It is widely used in education and influenced many newer systems and languages. REBOL extended this concept to professional programming. It was invented by Carl Sassenrath, the chief software designer of the famous Amiga computer, the first consumer multimedia system. Meta takes the next step by combining this design with the virtues of the C programming language, which has been the standard for software interoperability and performance for half a century.

• Seems to be primarily inspired by REBOL but designed to be faster [1].
• Can compile to various 8-bit Atari machines and αcτµαlly pδrταblε εxεcµταblε (which means it can run on almost anything) [2].
• Has an official Bluesky account, which AFAIK is the main social media presence.

meta-lang-examples (GitHub)

Try online ("console")