Angelic is a programming language which I was developing for Pioneers in Engineering for use in it's robotics control system known as Control System Next / Project Tenshi. However, after spending a several months developing Angelic, it was clear that Pioneers in Engineering would benefit more from using an off-the-shelf programming language. At that time, I switched Control System Next to use Lua, and stopped working on Anglic.
This repo exists to describe the language and document the work that has gone into it.
The Angelic language is designed to be used in an interactive environment. Specifically, the language implementation is made up of two components: a compiler and a virtual machine. The compiler is relatively heavyweight, and runs on the programmers computer. In comparison, the virtual machine is very small, and may reside on another computer, or even a microcontroller. The virtual machine is capable of reloading a program while it is executing, allowing interactive experimentation.
In order to ensure deterministic execution and meet real-time constraints, Angelic uses a system of linear types, similar to owned values in Rust. It also uses reference counting for immutable values. The language ensures that immutable values can never form a reference cycle, so reference counting can never create a memory leak.
Currently, the compiler is implemented (poorly) in JavaScript. Originally, it could be run in node.js or Mozilla's XULRunner.
The virtual machine is implemented in C99, and is relatively stable.
The Angelic compiler is currently capable of compiling some simple programs. It is able to parse, perform type inference, and generate a virtual machine package.
The virtual machine is able to load and execute packages. Details of how it works are described in angelic_instruction_set.md.
- The parser has basically no error handling.
- The parser has a lot of bugs.
- The type inferencer does not provide useable error messages.
- The type inferencer does not handle linear or reference counted types.
- The package format is extremely limiting.
- The language is missing a lot of desired features, like tuples, arrays, maps, objects, and methods.
- There's no standard library.