tricu/README.md
James Eversole 03e2f6b93e
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Some special characters in ids; new demos
Adds support for several special characters in identifiers. Adds a demo
for converting values to source code and another for checking equality.
Updates the existing demo and tests to reflect new names for functions
returning booleans.
2025-01-23 15:46:40 -06:00

3.3 KiB

tricu

Introduction

tricu (pronounced "tree-shoe") is a purely functional interpreted language implemented in Haskell. I'm developing tricu to further research the possibilities offered by the various forms of Tree Calculi.

tricu offers minimal syntax sugar yet manages to provide a complete, intuitive, and familiar programming environment. There is great power in simplicity. tricu offers:

  1. t operator behaving by the rules of Tree Calculus
  2. Function definitions/assignments
  3. Lambda abstractions eliminated to Tree Calculus forms
  4. List, Number, and String literals
  5. Parentheses for grouping function application

These features move us cleanly out of the turing tarpit territory that you may find yourself in if you try working only with the t operator.

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.

What does it look like?

tricu < -- Anything after `--` on a single line is a comment
tricu < id = (\a : a) -- Lambda abstraction is eliminated to tree calculus terms
tricu < head (map (\i : lconcat i " world!") [("Hello, ")])
tricu > "Hello,  world!"
tricu < id (head (map (\i : lconcat i " world!") [("Hello, ")]))
tricu > "Hello,  world!"

tricu < -- Intensionality! We can inspect the structure of a function.
tricu < triage = (\a b c : t (t a b) c)
tricu < test = triage "Leaf" (\z : "Stem") (\a b : "Fork")
tricu < test (t t)
tricu > "Stem"
tricu < -- We can even write a function to convert a term back to source code
tricu < toSource not?
tricu > "(t (t (t t) (t t t)) (t t (t t t)))"

Installation and Use

You can easily build and/or run this project using Nix.

  • Quick Start (REPL):
    • nix run git+https://git.eversole.co/James/tricu
  • Build executable in ./result/bin:
    • nix build git+https://git.eversole.co/James/tricu

./result/bin/tricu --help

tricu Evaluator and REPL

tricu [COMMAND] ... [OPTIONS]
  tricu: Exploring Tree Calculus

Common flags:
  -? --help       Display help message
  -V --version    Print version information

tricu [repl] [OPTIONS]
  Start interactive REPL

tricu eval [OPTIONS]
  Evaluate tricu and return the result of the final expression.

  -f --file=FILE  Input file path(s) for evaluation.
                    Defaults to stdin.
  -t --form=FORM  Optional output form: (tree|fsl|ast|ternary|ascii).
                    Defaults to tricu-compatible `t` tree form.

tricu decode [OPTIONS]
  Decode a Tree Calculus value into a string representation.

  -f --file=FILE  Optional input file path to attempt decoding.
                    Defaults to stdin.

Acknowledgements

Tree Calculus was discovered by Barry Jay.

treecalcul.us is an excellent website with an intuitive playground created by Johannes Bader that introduced me to Tree Calculus. If tricu sounds interesting but compiling this repo sounds like a hassle, you should check out his site.