Rivar

Rivar is a minimal, contract-first, class-based, garbage-collected programming language inspired by Eiffel.

It is being built from scratch in OCaml (with the help of LLMs), designed to bring native Design by Contract (DbC) to the modern developer's toolbox.

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Quick Start

So far this has been tested only on Ubuntu 24.04.

Prerequisites

• OCaml (recommended via opam)
• dune
• menhir

opam install dune menhir

Build

dune build

Run

Install Boehm GC

sudo apt-get install libgc-dev

Compile and Test

• Generate C code from Rivar source:

  ./_build/default/src/main.exe examples/greeter.rivar

• Compile generated C code with Boehm GC:

  gcc -std=c99 -o test examples/test-greeter.c out.c -lgc

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Example

class GREETER

feature
    name: STRING

    set_name(new_name: STRING)
        require new_name != ""
        do
            this->name = new_name
        ensure
            this->name != old this->name
        end

    greet()
        require this->name != ""
        do
            print(this->name)
        ensure
            result == true
        end

end

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Project Structure

rivar/
├── src/
│   ├── ast.ml             # Core [AST](https://en.wikipedia.org/wiki/Abstract_syntax_tree) definitions
│   ├── ir.ml              # IR types ([Intermediate Representation](https://en.wikipedia.org/wiki/Intermediate_representation))
│   ├── ir.mli             # IR interface
│   ├── irgen.ml           # AST -> IR lowering
│   ├── lexer.mll          # OCamllex lexer
│   ├── parser.mly         # Menhir parser
│   ├── codegen.ml         # IR -> C code generation
│   ├── typecheck.ml       # Type checker (WIP)
│   └── main.ml            # CLI compiler entry point (`rivarc`)
├── examples/
│   ├── account.rivar      # Sample Rivar class
│   ├── greeter.rivar      # Sample Rivar class with strings
│   ├── test-account.c     # Test harness for `account.rivar`
│   └── test-greeter.c     # Test harness for `greeter.rivar`
├── out.c                  # Generated C output (from `rivarc`)
├── out.h                  # Generated C header
├── dune-project           # Dune project file
├── .gitignore             # Ignores compiled artifacts and test binaries
└── README.md              # You're looking at it

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Philosophy

Rivar isn't about speed or syntax gimmicks. It's about truth in code.
Contracts aren't optional: they are the code.

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License

MIT