57 lines
2.1 KiB
Markdown
57 lines
2.1 KiB
Markdown
# sapling
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## Introduction
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sapling is a "micro-language" that [I'm](https://eversole.co) working on to investigate [Tree Calculus](https://github.com/barry-jay-personal/typed_tree_calculus/blob/main/typed_program_analysis.pdf) .
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It offers a minimal amount of syntax sugar yet provides a complete and intuitive programming environment. Sapling offers:
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- `t` operator behaving by the rules of Tree Calculus
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- Function ("variable") definitions
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- Lambda abstractions
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- List, Number, and String literals
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## What does it look like?
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```
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-- Anything after `--` on a line is a comment
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-- We can define functions or "variables" as tree calculus values
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false = t
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_ = t
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true = t t
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-- We can define functions as lambda expressions that are eliminated to tree
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-- calculus terms.
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id = (\a : a) -- t (t (t t)) t
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triage = (\a b c : t (t a b) c)
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triage = (\a b c : t (t a b) c)
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-- Intensionality !!!
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test = triage "Leaf" (\_ : "Stem") (\_ _ : "Fork")
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-- REPL
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-- `sapling <` is the input prompt
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-- `sapling >` is the Tree Calculus form output. Most are elided below.
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-- `DECODE -:` is an attempt to interpret the TC output as strings/numbers.
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sapling < test t
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sapling > Fork (Fork Leaf (Fork ...) ... )
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DECODE -: "Leaf"
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sapling < test (t t)
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DECODE -: "Stem"
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sapling < test (t t t)
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DECODE -: "Fork"
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sapling < map (\i : listConcat i " is super cool!") [("He") ("She") ("Everybody")]
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DECODE -: ["He is super cool!", "She is super cool!", "Everybody is super cool!"]
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```
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## Installation
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You can easily build and/or run this project using [Nix](https://nixos.org/download/).
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- Build REPL binary: `nix build git+https://git.eversole.co/James/sapling`
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- Run REPL: `nix run git+https://git.eversole.co/James/sapling`
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## Acknowledgements
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Tree Calculus was discovered by [Barry Jay](https://github.com/barry-jay-personal/blog).
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[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.
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