# sapling

## Introduction

sapling is a "micro-language" that I'm working on to investigate [Tree Calculus](https://github.com/barry-jay-personal/typed_tree_calculus/blob/main/typed_program_analysis.pdf) .

It offers a minimal amount of syntax sugar:

- `t` operator behaving by the rules of Tree Calculus
- Function ("variable") definitions
- Lambda abstractions
- List, Number, and String literals (WIP)

This is an active experimentation project by [someone who has no idea what they're doing](https://eversole.co).

## What does it look like?

```
false = t
true = t t
id = (\\a : a)
triage = (\\a b c : t (t a b) c) 
match_bool = (\\ot of : triage of (\\z : ot) t)
and = match_bool id (\\z : false)
if = (\\cond then else : t (t else (t t then)) t cond)
triage = (\\a b c : t (t a b) c)
test = triage \"leaf\" (\\z : \"stem\") (\\a b : \"fork\")

sapling < test t
sapling > Fork (...)
DECODE -: "leaf"
sapling < test (t t)
sapling > Fork (...)
DECODE -: "stem"
sapling < test (t t t)
sapling > Fork (...)
DECODE -: "fork"
```

## How to use

For now, you can easily build and run this project using Nix:

1. Clone the repository:
    a. `git clone ssh://git.eversole.co/sapling.git`
    b. `git clone https://git.eversole/sapling.git`
1. Run the REPL: `nix run`

## Acknowledgements 

Tree Calculus was discovered by [Barry Jay](https://github.com/barry-jay-personal/blog). 

[treecalcul.us](https://treecalcul.us) is an excellent website with an intuitive playground created by [Johannes Bader](https://johannes-bader.com/) that introduced me to Tree Calculus. If sapling sounds interesting but compiling this repo sounds like a hassle, you should check out his site.