918d929c09
To encourage organizing code in a way that helps in understanding, I have implemented the common idiom of requiring a `main` function. In tricu and other functional languages, it is usually placed near the top of the module. The evaluator gracefully handles the situation of passing multiple files where the intermediary "library" files do not have main functions.
89 lines
3.1 KiB
Markdown
89 lines
3.1 KiB
Markdown
# tricu
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## Introduction
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tricu (pronounced "tree-shoe") is a purely functional interpreted language implemented in Haskell. It is fundamentally based on the application of [Tree Calculus](https://github.com/barry-jay-personal/typed_tree_calculus/blob/main/typed_program_analysis.pdf) terms, but minimal syntax sugar is included to provide a useful programming tool. tricu is under active development and you can expect breaking changes with nearly every commit.
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tricu is the word for "tree" in Lojban: `(x1) is a tree of species/cultivar (x2)`.
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## Features
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- Tree Calculus operator: `t`
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- Assignments: `x = t t`
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- Lambda abstraction syntax: `id = (\a : a)`
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- List, Number, and String literals: `[(2) ("Hello")]`
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- Function application: `not (not false)`
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- Higher order/first-class functions: `map (\a : lconcat a "!") [("Hello")]`
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- Intensionality blurs the distinction between functions and data (see REPL examples)
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- Immutability
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## REPL examples
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```
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tricu < -- Anything after `--` on a single line is a comment
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tricu < id = (\a : a) -- Lambda abstraction is eliminated to tree calculus terms
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tricu < head (map (\i : lconcat i " world!") [("Hello, ")])
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tricu > "Hello, world!"
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tricu < id (head (map (\i : lconcat i " world!") [("Hello, ")]))
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tricu > "Hello, world!"
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tricu < -- Intensionality! We can inspect the structure of a function or data.
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tricu < triage = (\a b c : t (t a b) c)
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tricu < test = triage "Leaf" (\z : "Stem") (\a b : "Fork")
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tricu < test (t t)
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tricu > "Stem"
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tricu < -- We can even convert a term back to source code (/demos/toSource.tri)
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tricu < toSource not?
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tricu > "(t (t (t t) (t t t)) (t t (t t t)))"
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tricu < -- or calculate its size (/demos/size.tri)
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tricu < size not?
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tricu > 12
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```
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## Installation and Use
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[Releases are available for Linux.](https://git.eversole.co/James/tricu/releases)
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Or 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 tricu and return the result of the final expression.
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-f --file=FILE Input file path(s) for evaluation.
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Defaults to stdin.
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-t --form=FORM Optional output form: (tree|fsl|ast|ternary|ascii|decode).
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Defaults to tricu-compatible `t` tree form.
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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 Tree Calculus code playground created by [Johannes Bader](https://johannes-bader.com/) that introduced me to Tree Calculus.
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