raviqqe / pen-1

The programming language for scalable software development

Pen programming language

Pen is the programming language for scalable software development, focused on software maintainability and portability.

import Os'Context { Context }
import Os'File
import Os'Process

sayHello = \(ctx Context) none | error {
  File'Write(ctx, File'StdOut(), "Hello, world!\n")?

  none
}

main = \(ctx context) none {
  e = sayHello(ctx.Os)

  if _ = e as none {
    none
  } else if error {
    Process'Exit(ctx.Os, 1)
  }
}

Install

See Install.

Documentation

• Getting started
• Language reference
• Code examples
  • Applications and libraries
  • Snippets

Vision

Pen aims to make large-scale software development efficient where a number of people develop software together for a long time. To realize that, it focuses on software maintainability and portability.

• Maintainability
  • Simplicity: The language is small and easy to learn but also full featured.
  • Testability: Unit tests are always fast and reliable.
  • Modifiability: Developers can change application logic independently from implementation details.
• Portability
  • Programs written in Pen can be ported to different platforms including WebAssembly.

Features

Minimal language

• Its syntax and type system are small, simple, and easy to learn.
• Yet, the language supports all the modern features.

Concurrent/parallel computation

• The language and its runtime enables thread-safe concurrent/parallel computation.
• For more information, see Concurrency and parallelism.

System packages

• System packages encapsulate side effects as separate packages.
• No other packages have side effects unless injected them into explicitly.

Reliable testing

• Unit tests are always deterministic and fast.
• No flaky or slow tests bother developers.

Even more...

• Static typing
• Immutable values
• Pure functions by default
• Errors as values
• Asynchronous I/O
• Cross compile
• Rust/C Foreign Function Interface (FFI)

License

Pen is dual-licensed under MIT and Apache 2.0.