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NLS Compiler

The source code is English. The compiled artifact is Python.

NLS is a programming language where specifications are written in plain English that anyone can read—managers, auditors, domain experts—not just programmers. The nlsc compiler translates .nl files into executable Python with full type hints, validation, and documentation.

Why NLS?

  • Readable by everyone — Non-programmers can review business logic
  • Auditable — Clear mapping from intent to implementation
  • Testable — Specifications include test cases
  • Versionable — Lock files ensure reproducibility
  • Toolable — Tree-sitter grammar enables IDE support

Quick Example

@module calculator
@target python

[divide]
PURPOSE: Divide two numbers safely
INPUTS:
  - numerator: number
  - divisor: number
GUARDS:
  - divisor must not be zero -> ValueError("Cannot divide by zero")
RETURNS: numerator / divisor

Compiles to:

def divide(numerator: float, divisor: float) -> float:
    """Divide two numbers safely."""
    if divisor == 0:
        raise ValueError("Cannot divide by zero")
    return numerator / divisor

Installation

pip install nlsc

pip install "nlsc[treesitter]"

Search "NLS" in Extensions, or: 

ext install mnehmos.nls-language

Project Status

Component Status
Parser (regex) ✅ Complete
Parser (tree-sitter) ✅ Complete
Python emitter ✅ Complete
Type generation ✅ Complete
Guard validation ✅ Complete
Dataflow analysis ✅ Complete
Test runner ✅ Complete
Property-based testing ✅ Complete
Type invariants ✅ Complete
Watch mode ✅ Complete
GitHub Action ✅ Complete
PyPI distribution ✅ Complete
VS Code extension ✅ Complete
LSP server ✅ Complete
Windows installer ✅ Complete
TypeScript target 🔜 Planned

239 tests passing — Production-ready for Python target.

Get Started