🧪 120/120 tests passing →

Externum v3.0 "Sentient"

A fully functional programming language that fuses Python's readability, binary performance, and Bash's system control into one paradigm. Compiles to three targets at once: Python, Bash, and binary.

What It Can Do

Area	Support
Data types	lists, dicts, tuples, sets, f-strings, 0b/0x literals
Control flow	if/elif/else, while, for ... in, break/continue, try/except/finally, with, assert
Functions	default params, *args/**kwargs, lambdas, closures, generators (yield)
OOP	classes, inheritance, methods, self
Modules	import, own .ext modules, standard library
Expressions	full operator precedence, bitwise ops, ternary, comprehensions
Shell	inline bash `cmd` and %% ... %% blocks
Tooling	REPL, 3 compile targets, argv, browser playground

Quick Start

git clone https://github.com/BartoszOsiej/externum.git
cd Externum
pip install -e .            # Python 3.10+

externum --version          # Externum 3.0.0

# Run a program
externum run examples/pokedex.ext

# Interactive shell
externum repl

Example

# fibonacci.ext
fn fibonacci(n: int) -> int {
    if n <= 1 {
        return n
    }
    return fibonacci(n - 1) + fibonacci(n - 2)
}

for i in range(20) {
    print(f"fib({i}) = {fibonacci(i)}")
}

Three Compile Targets

Target	Use Case
Python	Full-featured execution with Python's ecosystem
Bash	System scripts, cron jobs, shell automation
Binary	Standalone executable, no runtime dependencies

# Compile to all three
externum compile examples/fibonacci.ext

# Output:
#   examples/fibonacci.py
#   examples/fibonacci.sh
#   examples/fibonacci.bin

Architecture

┌──────────────┐     ┌──────────────┐     ┌──────────────┐
│  .ext source │────►│    Parser    │────►│     AST      │
│  (Externum)  │     │ (recursive  │     │              │
│              │     │  descent)   │     │              │
└──────────────┘     └──────────────┘     └──────┬───────┘
                                                  │
                              ┌───────────────────┼───────────────────┐
                              ▼                   ▼                   ▼
                     ┌──────────────┐    ┌──────────────┐    ┌──────────────┐
                     │  Python      │    │  Bash        │    │  Binary      │
                     │  transpiler  │    │  transpiler  │    │  compiler    │
                     └──────────────┘    └──────────────┘    └──────────────┘

Features

Standard Library

Written in Externum itself — the stdlib proves the language is expressive enough to build real programs:

• math.ext — math functions
• string.ext — string manipulation
• io.ext — file I/O
• list.ext — list operations
• random.ext — random number generation

Browser Playground

The Externum playground executes entirely in your browser — the transpiler (written in Python) runs through WebAssembly (Pyodide), with no server at all.

Module System

# Import own modules
import utils
from math import sqrt

# Import with alias
import collections as coll

Tests

120/120 tests passing — comprehensive coverage of:

• Parser correctness (all syntax constructs)
• Transpiler output (Python, Bash, binary)
• Runtime behaviour (all data types, control flow)
• Standard library functions
• Edge cases and error handling

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See also: Syntax · Compiler · Architecture · Standard Library · Playground