https://github.com/omentic/chrysanthemum

A blossoming type system.
https://github.com/omentic/chrysanthemum

bidirectional-typechecking lambda-calculus rust type-system typeclasses

Last synced: 13 days ago
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A blossoming type system.

• Host: GitHub
• URL: https://github.com/omentic/chrysanthemum
• Owner: omentic
• License: 0bsd
• Created: 2023-04-05T07:17:16.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2023-07-20T22:47:13.000Z (over 1 year ago)
• Last Synced: 2024-11-02T12:42:34.836Z (2 months ago)
• Topics: bidirectional-typechecking, lambda-calculus, rust, type-system, typeclasses
• Language: Rust
• Homepage: https://apropos.codes/chrysanthemum/
• Size: 2.95 MB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# chrysanthemum

chrysanthemum is a simple language with a complex type system, initially written as a term project for CPSC 539.

It implements a number of features from the excellent *Types and Programming Languages*, including:

- The simply typed lambda calculus

- Bidirectional type checking and subtyping support

- A somewhat complex type system: including support for:

  - `unit`, `bool`, `int`, `nat`, `float`, `str`,

  - `struct`, `tuple`, `union`, `list`, `array`, `slice`,

  - `interface`, `empty`, `error`

## todo

- [x] the simple lambda calculus: implement `execute`

- [x] to be fancy: implement `parse`

- [x] to lose my sanity: implement `parse_file`

- [x] bidirectional typechecking: implement `infer` and `check`

- [x] extend to additional basic types: refactor `Term`

- [x] extend to complex types: improve `subtype`

- [x] meet my original standards: implement `interface`

- [ ] make complex types useful: implement `access`

- [ ] type classes: implement `monomorphize`

- [ ] simple effects: extend `ast`

- [x] testtesttest

## architecture

```bash

src/

src/main.rs    # the user facing program

src/simple.rs  # the simple lambda calculus: execution

src/ast.rs     # the fundamental representation of types and terms

src/bidirectional.rs # the core of the language: checking, inference

src/unification.rs   # an alternate core: checking and inference by unification

src/parser.rs        # parses user programs into proper data structures

src/monomorphize.rs  # a monomorphization pass for type classes

src/effects.rs       # code for effects idk

test/ # various tests

```

## bibliography

- [Types and Programming Languages](https://www.cis.upenn.edu/~bcpierce/tapl/)

- [Advanced Topics in Types and Programming Languages](https://www.cis.upenn.edu/~bcpierce/attapl/)

- [Bidirectional Typing Rules: A Tutorial](https://www.davidchristiansen.dk/tutorials/bidirectional.pdf)

- [Bidirectional Typechecking](https://research.cs.queensu.ca/home/jana/bitype.pdf)

- [Bidirectional Type Class Instances](https://arxiv.org/pdf/1906.12242.pdf)

- [Typechecking for Higher-Rank Polymorphism](https://arxiv.org/pdf/1306.6032.pdf)

- [How to make ad-hoc polymorphism less ad-hoc](https://dl.acm.org/doi/pdf/10.1145/75277.75283)