chen_lang

A tiny, expression-oriented programming language written in Rust

🇨🇳 中文版

chen_lang is a dynamic, interpreted programming language designed for learning and experimentation. It features a clean syntax, expression-based control flow, and first-class functions.

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✨ Key Features

• Expression-Oriented: if/else blocks and code blocks are expressions that return values.
• Dynamic Typing: Supports Integers, Floats, Strings, Booleans, and Null.
• Functions: First-class functions with implicit returns.
• Control Flow: if/else expressions, for loops, break, and continue.
• Object System: Supports object literals, property access, indexing, and metatables.
• Scope Isolation: Block-scoped variables.

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🚀 Quick Start

1. Hello World & String Operations

let name = "Chen Lang"
println("Hello, " + name + "!")
# Output: Hello, Chen Lang!

2. If/Else as Expression

In chen_lang, if/else is an expression, meaning it returns a value.

let a = 10
let result = if a > 5 {
    "Greater"
} else {
    "Smaller"
}
println(result) 
# Output: Greater

3. Functions & Implicit Return

Functions implicitly return the value of the last expression.

def add(a, b) {
    a + b  # Implicit return
}

let sum = add(3, 5)
println(sum)
# Output: 8

4. Recursive Fibonacci

def fib(n) {
    if n <= 1 {
        n
    } else {
        fib(n - 1) + fib(n - 2)
    }
}

println(fib(10))
# Output: 55

5. Loops & Logic

# Print multiplication table
let i = 1
for i <= 9 {
    let j = 1
    for j <= i {
        let prod = i * j
        print(j + "x" + i + "=" + prod + " ")
        j = j + 1
    }
    println("")
    i = i + 1
}

6. Object System

# Object literal
let person = #{ 
    name: "Alice", 
    age: 25 
}

# Property access
println(person.name)  # Output: Alice

# Property assignment
person.age = 26

# Index access
let key = "name"
println(person[key])  # Output: Alice

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🛠️ Language Reference

Data Types

• Integer: 1, 42, -10
• Float: 3.14, -0.01
• String: "Hello World"
• Boolean: true, false
• Null: null (implicit return for empty blocks or if without else)

Operators

• Arithmetic: +, -, *, /, %
• Comparison: >, >=, <, <=, ==, !=
• Logical: &&, ||, !

Comments

# This is a single-line comment

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📝 TODO / Roadmap

• Core: Integers, Booleans, Arithmetic, Logic
• Control Flow: if/else (expression), for loops, break, continue
• Functions: Definition, Call, Recursion, Implicit Return
• Types: Floats, Strings
• Object System: Object literals, property access, indexing, metatables (can be used as arrays)
• Standard Library: File I/O, Math functions
• Error Handling: Try/Catch or Result type

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📄 License

MIT License