T — A Functional Language for Tabular Data

T is an experimental programming language for declarative, functional manipulation of tabular data. Inspired by R’s tidyverse and OCaml’s type discipline, T aims to make data manipulation clear, expressive, and extensible.

Status: Very early, exploratory phase. Entirely generated via iterative AI prompts.

Design Goals

• Data analysis as a pipeline
• DataFrame-first operations like select(), filter()
• 1-indexed
• Expression-oriented, functional style
• Minimal OCaml core
• Non-standard evaluation: select(name, age)
• Extensible built-ins like print()
• REPL-first exploration
• Package-based modularity using Nix Flakes!

Why T?

T is not trying to replace R. Instead, it’s a small, focused language for data wrangling, graphics, and basic stats — without general-purpose baggage.

• Minimal: learn the whole language
• Self-contained: all functions inspectable
• Purpose-built: just for structured data

Perfect for teaching, scripting, or exploratory work — with a REPL-first workflow.

Example

data = read_csv("data.csv")
select(data, name, age)
  

Also supports:

• R-style lambdas: \(x) x + 1
• Python-style comprehensions: [x * x for x in numbers if x > 2]
• Python-style dicts: {name: "Alice", age: 30}

Standard Packages

• core: functional tools like map
• stats: statistical tools like mean, sd
• colcraft: table ops like select, mutate

Each package is one file per function, e.g. colcraft.select.ml

Package Philosophy

Nix Flakes-powered decentralized registry. All packages live in their respective GitHub repos. A curated, centralized registry of official packages is planned. Avoids dependency hell and all contributions are transparent.

• Minimal dependency graph
• Clear contribution via PRs
• No version drift or registry sprawl

Project Structure

.
├── flake.nix            
├── ast.ml               
├── parser.ml            
├── lexer.ml             
├── eval.ml              
├── repl.ml              
├── csv_reader.ml        
└── packages/
    ├── core/
    │   └── map.t
    ├── stats/
    │   └── mean.t
    └── colcraft/
        └── select.t
  

Building

nix develop
dune exec ./repl.exe
  

Contributing

User packages can be merged into the centralized package registry, or you can keep them private.

License: EUPL v1.2.