Zen-C: Write like a high-level language, run like C

Modern Ergonomics. Zero Overhead. Pure C.

Write like a high-level language, run like C.

git clone https://github.com/z-libs/Zen-C.git
cd Zen-C
make
sudo make install

# Compile and run
zc run hello.zc

# Build executable
zc build hello.zc -o hello

# Interactive Shell
zc repl

1. Variables and Constants

var x = 42;                 // Inferred as int
const PI = 3.14159;         // Compile-time constant
var explicit: float = 1.0;  // Explicit type

//> immutable-by-default

var x = 10;
// x = 20; // Error: x is immutable

var mut y = 10;
y = 20;    // OK

var ints: int[5] = {1, 2, 3, 4, 5};
var zeros: [int; 5]; // Zero-initialized

var pair = (1, "Hello");
var x = pair.0;
var s = pair.1;

struct Point {
    x: int;
    y: int;
}

// Struct initialization
var p = Point { x: 10, y: 20 };

// Bitfields
struct Flags {
    valid: U8 : 1;
    mode:  U8 : 3;
}

enum Shape {
    Circle(float),      // Holds radius
    Rect(float, float), // Holds width, height
    Point               // No data
}

union Data {
    i: int;
    f: float;
}

fn add(a: int, b: int) -> int {
    return a + b;
}

// Named arguments supported in calls
add(a: 10, b: 20);

var factor = 2;
var double = x -> x * factor;  // Arrow syntax
var full = fn(x: int) -> int { return x * factor; }; // Block syntax

if x > 10 {
    print("Large");
} else if x > 5 {
    print("Medium");
} else {
    print("Small");
}

// Ternary
var y = if x > 10 ? 1 : 0;

match val {
    1 => print("One"),
    2 | 3 => print("Two or Three"),
    4..10 => print("Range"),
    _ => print("Other")
}

// Destructuring Enums
match shape {
    Circle(r) => print(f"Radius: {r}"),
    Rect(w, h) => print(f"Area: {w*h}"),
    Point => print("Point")
}

// Range
for i in 0..10 { ... }
for i in 0..10 step 2 { ... }

// Iterator/Collection
for item in vec { ... }

// While
while x < 10 { ... }

// Infinite with label
outer: loop {
    if done { break outer; }
}

// Repeat
repeat 5 { ... }

// Guard: Execute else and return if condition is false
guard ptr != NULL else { return; }

// Unless: If not true
unless is_valid { return; }

var f = fopen("file.txt", "r");
defer fclose(f);

autofree var types = malloc(1024);

impl Drop for MyStruct {
    fn drop(mut self) {
        free(self.data);
    }
}

8. Object Oriented Programming

impl Point {
    // Static method (constructor convention)
    fn new(x: int, y: int) -> Point {
        return Point{x: x, y: y};
    }

    // Instance method
    fn dist(self) -> float {
        return sqrt(self.x * self.x + self.y * self.y);
    }
}

trait Drawable {
    fn draw(self);
}

impl Drawable for Circle {
    fn draw(self) { ... }
}

struct Entity { id: int; }
struct Player {
    use Entity; // Adds 'id' field
    name: string;
}

// Generic Struct
struct Box<T> {
    item: T;
}

// Generic Function
fn identity<T>(val: T) -> T {
    return val;
}

10. Concurrency (Async/Await)

async fn fetch_data() -> string {
    // Runs in background
    return "Data";
}

fn main() {
    var future = fetch_data();
    var result = await future;
}

comptime {
    print("Compiling...");
}

var png = embed "assets/logo.png";

import plugin "regex"
var re = regex! { ^[a-z]+$ };

// Syntax: : out(var) : in(var) : clobber(reg)
// Uses {var} placeholder syntax for readability

fn add(a: int, b: int) -> int {
    var result: int;
    asm {
        "add {result}, {a}, {b}"
        : out(result)
        : in(a), in(b)
        : clobber("cc")
    }
    return result;
}

//> include: ./include
//> lib: ./libs
//> link: -lraylib -lm
//> cflags: -Ofast
//> pkg-config: gtk+-3.0

import "raylib.h"

fn main() { ... }

Compiler Support & Compatibility

zc run app.zc --cc clang
zc run app.zc --cc zig

# Compile and run a Zen C program with Zig
zc run app.zc --cc zig

# Build the Zen C compiler itself with Zig
make zig

# Run all tests (GCC)
make test

# Run specific test
./zc run tests/test_match.zc

# Run with different compiler
./tests/run_tests.sh --cc clang
./tests/run_tests.sh --cc zig
./tests/run_tests.sh --cc tcc