120 lines
4.9 KiB
Markdown
120 lines
4.9 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.
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*tricu is under active development and you should expect breaking changes with 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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- **Immutable definitions**: `x = t t`
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- **Lambda abstraction**: `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 : append a "!") [("Hello")]`
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- **Intensionality** blurs the distinction between functions and data (see REPL examples)
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- **Content-addressed store**: save, version, tag, and recall your tricu terms.
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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 : append i " world!") [("Hello, ")])
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tricu > "Hello, world!"
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tricu < id (head (map (i : append 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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tricu < !help
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tricu version 0.20.0
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Available commands:
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!exit - Exit the REPL
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!clear - Clear the screen
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!reset - Reset preferences for selected versions
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!help - Show tricu version and available commands
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!output - Change output format (tree|fsl|ast|ternary|ascii|decode)
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!definitions - List all defined terms in the content store
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!import - Import definitions from file (definitions are stored)
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!watch - Watch a file for changes (definitions are stored)
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!versions - Show all versions of a term by name
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!select - Select a specific version of a term for subsequent lookups
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!tag - Add or update a tag for a term by hash or name
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```
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## Content Store
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tricu uses a "content store" SQLite database that saves and versions your definitions persistently.
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* **Persistent definitions:** Any term you define in the REPL is automatically saved.
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* **Content-addressed:** Terms are stored based on a SHA256 hash of their content. This means identical terms are stored only once, even if they have different names.
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* **Versioning and history:** If you redefine a name, the Content Store keeps a record of previous definitions associated with that name. You can explore the history of a term and access older versions.
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* **Tagging:** You can assign tags to versions of your terms to organize and quickly switch between related function versions.
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* **Querying:** The store allows you to search for terms by name, hash, or tags.
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## Installation and Use
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You can easily build and 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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## Collaborating
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I am happy to accept issue reports, pull requests, or questions about tricu [via email](mailto:james@eversole.co).
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If you want to collaborate but don't want to email back-and-forth, please reach out via email once to let me know and I will provision a git.eversole.co account for you.
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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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