langex 0.3.1

Extended Language Support for Python

LangEx

Extended Language Support for Python

Installation

pip install langex

About

LangEx is an experimental Python library that introduces additional language-level constructs using decorators, metadata inspection, and runtime validation.

It focuses on enabling capabilities that Python does not strictly enforce by default, such as interface-like structures, structured metadata, and runtime type validation.

The project builds small language utilities that operate on Python objects (functions, classes, and other callables) to inspect, validate, and extend their behavior while remaining fully compatible with standard Python.

Features

• Interface-like constructs for Python classes
• Metadata extraction for Python objects and callables
• Runtime validation utilities
• Decorator-based language extensions
• Runtime argument and return type checking
• Lightweight core inspection tools

Example

Defining and using an Interface

from langex.core.classes import implements, interface
from langex.core.functions import args_required, returns

@interface
class InterfaceClass:
  @args_required(int)
  @returns(int)
  def method1(self, a: int) -> int:
    ...

  @args_required(str)
  @returns(str)
  def method2(self, b: str) -> str:
    ...

@implements(InterfaceClass)
class ImplementationClass:
  def __init__(self, factor):
    self.factor = factor

  def method1(self, a: int) -> int:
    return a * self.factor

  def method2(self, b: str) -> str:
    return b.upper() * self.factor

instance = ImplementationClass(3)
print(instance.method1(5)) # prints 15 in console
print(instance.method2("hi")) # prints "HIHIHI" in console
print(instance.method1("5")) # raises Langex Validation Error
print(instance.method2(5)) # raises Langex Validation Error

Runtime Type Enforcement

from langex.core.functions import args_required, returns

@args_required(int, int)
@returns(int)
def add(a, b):
  return a + b

print(add(1, 2)) # prints the integer 3 in console
print(add("1", "2")) # raises Langex Validation Error

Project Structure

langex
├── __init__.py
├── __main__.py
├── classes
│   ├── __init__.py
│   ├── class_meta.py
│   └── methods_meta.py
├── constants
│   ├── __init__.py
│   ├── contents.py
│   ├── keys.py
│   └── labels.py
├── core
│   ├── __init__.py
│   ├── classes.py
│   └── functions.py
├── errors
│   ├── __init__.py
│   ├── instantiation.py
│   ├── langex.py
│   ├── misapplication.py
│   ├── unimplemented.py
│   └── validation.py
├── functions
│   ├── __init__.py
│   ├── args_meta.py
│   ├── function_meta.py
│   ├── returns_meta.py
│   ├── signature.py
│   └── signature_parser.py
├── utils
│   ├── __init__.py
│   ├── extracter.py
│   └── matcher.py
└── validation
    ├── __init__.py
    ├── kw_args_validator.py
    ├── pos_args_validator.py
    ├── returns_validator.py
    └── validator.py

Module Overview

• The core module contains the core decorators and utilities for language extensions.
• The constants module contains constant strings and keys used across the project for metadata, attributes and validation.
• The classes module contains tools for class inspection and interface-like constructs.
• The functions module contains tools for function metadata and signature inspection.
• The validation modules contain logic for validating function arguments and return values at runtime.
• The utils module contains helper functions for type matching and other utilities.
• The errors module defines custom exceptions for validation and other errors.

Design Philosophy

LangEx is designed around a few principles:

• Pure Python implementation
• Explicit developer intent
• Small composable language utilities

Rather than acting as a framework, LangEx provides foundational language tools that can be used to build higher-level abstractions.

Status

Experimental and under active development.
APIs and structure may evolve as the project grows.

Links

• PyPI
• GitHub
• License

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