95 lines
3.7 KiB
Markdown
95 lines
3.7 KiB
Markdown
# tricu
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## Introduction
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tricu (pronounced like "tree-shoe" in English) is a purely functional interpreted language implemented in Haskell. [I'm](https://eversole.co) developing tricu to further research the possibilities offered by the various forms of [Tree Calculi](https://github.com/barry-jay-personal/typed_tree_calculus/blob/main/typed_program_analysis.pdf).
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tricu offers minimal syntax sugar yet manages to provide a complete, intuitive, and familiar programming environment. There is great power in simplicity. tricu offers:
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1. `t` operator behaving by the rules of Tree Calculus
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1. Function definitions/assignments
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1. Lambda abstractions eliminated to Tree Calculus forms
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1. List, Number, and String literals
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1. Parentheses for grouping function application
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These features move us cleanly out of the [turing tarpit](https://en.wikipedia.org/wiki/Turing_tarpit) territory that you may find yourself in if you try working only with the `t` operator.
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tricu is the word for "tree" in Lojban: `(x1) is a tree of species/cultivar (x2)`. This project was named "sapling" until I discovered the name is already being used for other (completely unrelated) programming language development projects.
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## What does it look like?
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```
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-- Anything after `--` on a single 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) -- `id` evaluates to the TC form of: t (t (t t)) t
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triage = (\a b c : t (t a b) c)
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-- Intensionality! We can inspect program structure, not just inputs/outputs:
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test = triage "Leaf" (\_ : "Stem") (\_ _ : "Fork")
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-- REPL
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-- `tricu <` is the input prompt
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-- `tricu >` is the Tree Calculus form output. Most are elided below.
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-- `READ -:` is an attempt to interpret the TC output as strings/numbers.
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tricu < test t
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tricu > Fork (Fork Leaf (Fork ...) ... )
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READ -: "Leaf"
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tricu < test (t t)
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READ -: "Stem"
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tricu < test (t t t)
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READ -: "Fork"
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tricu < map (\i : listConcat i " is super cool!") [("Tree Calculus") ("Intensionality") ("tricu")]
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READ -: ["Tree Calculus is super cool!", "Intensionality is super cool!", "tricu is super cool!"]
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```
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## Installation and Use
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You can easily build and/or run this project using [Nix](https://nixos.org/download/).
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- Quick Start (REPL):
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- `nix run git+https://git.eversole.co/James/tricu`
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- Build executable in `./result/bin`:
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- `nix build git+https://git.eversole.co/James/tricu`
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`./result/bin/tricu --help`
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```
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tricu Evaluator and REPL
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tricu [COMMAND] ... [OPTIONS]
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tricu: Exploring Tree Calculus
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Common flags:
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-? --help Display help message
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-V --version Print version information
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tricu [repl] [OPTIONS]
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Start interactive REPL
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tricu eval [OPTIONS]
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Evaluate a file and return the result of the expression in the final line
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-f --file=FILE Optional input file path for evaluation.
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Defaults to stdin.
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-o --output=OUTPUT Optional output file path for resulting output.
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Defaults to stdout.
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-t --form=FORM Optional output form: (fsl|tree|ast|ternary|ascii).
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Defaults to fsl.
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tricu decode [OPTIONS]
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Decode a Tree Calculus value into a string representation
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-f --file=FILE Optional input file path to attempt decoding.
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Defaults to stdin.
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```
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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 tricu sounds interesting but compiling this repo sounds like a hassle, you should check out his site.
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