Polang

A simple programming language with ML-inspired syntax and an MLIR/LLVM backend.

Features

• ML-inspired syntax: Haskell-style definitions, type annotations, first-class functions
• Type inference: Hindley-Milner style type inference with polymorphism
• MLIR backend: Custom Polang dialect lowered through MLIR to LLVM IR
• Interactive REPL: JIT compilation with state persistence
• Comprehensive testing: Unit tests, lit tests, sanitizers, and coverage

Quick Start

Building

The project uses Docker for a consistent build environment:

# Start the development container
docker/docker_run.sh

# Configure and build (inside container)
cmake -S. -Bbuild -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -DCMAKE_PREFIX_PATH="/usr/lib/llvm-20"
cmake --build build -j$(nproc)

Or from outside the container:

docker exec polang cmake -S. -Bbuild -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -DCMAKE_PREFIX_PATH="/usr/lib/llvm-20"
docker exec polang cmake --build build -j$(nproc)

Running

Interactive REPL:

./build/bin/PolangRepl

Example session:

$ ./build/bin/PolangRepl
Polang REPL (type 'exit' or Ctrl+D to quit)
> 1 + 2
3 : i64
> x = 5
> x * 2
10 : i64
> double(n) = n * 2
> double(21)
42 : i64
> if x > 3 then true else false
true : bool
> exit

Compile to LLVM IR:

echo "x = 42" | ./build/bin/PolangCompiler

Run a source file:

./build/bin/PolangRepl example/fibonacci.po

Testing

# Run all tests
ctest --test-dir build --output-on-failure

# Run example programs
for f in example/*.po; do echo "=== $(basename $f) ==="; ./build/bin/PolangRepl "$f"; done

Documentation

Document	Description
Syntax	Language syntax reference
TypeSystem	Type system and inference
Architecture	Project structure, components, MLIR lowering
Building	Build instructions, dependencies
Development	Code style and tooling
Testing	Test infrastructure and CI/CD

Project Structure

polang/
├── parser/          # Lexer, parser, type checker
├── compiler/        # LLVM IR compiler
├── repl/            # Interactive REPL with JIT
├── mlir/            # Polang MLIR dialect and lowering
├── tests/           # Unit tests and lit tests
├── example/         # Example programs
├── doc/             # Documentation
├── scripts/         # Development scripts
└── docker/          # Docker build environment

Dependencies

• CMake 3.20+
• LLVM 20+ with MLIR
• Bison and Flex
• GCC or Clang

License

See LICENSE for details.