Zen C is a modern systems programming language that compiles to human-readable GNU C/C11. It provides a rich feature set including type inference, pattern matching, generics, traits, async/await, and manual memory management with RAII capabilities, all while maintaining 100% C ABI compatibility.

Join the discussion, share demos, ask questions, or report bugs in the official Zen C Discord server!

• Discord: Join here
• RFCs: Propose features

The Zen C project consists of several repositories. Below you can find the primary ones:

Check out these projects built with Zen C:

• ZC-pong-3ds: A Pong clone for the Nintendo 3DS.
• zen-c-parin: A basic example using Zen C with Parin.
• almond: A minimal web browser written in Zen C.

git clone https://github.com/zenc-lang/zenc.git
cd zenc
make clean # remove old build files
make
sudo make install

make format       # Auto-format all source files with clang-format
make format-check # Verify formatting without changing files
make lint         # Run format-check + shellcheck on test scripts
make bench        # Run performance benchmarks
make WERROR=1     # Build with -Werror (warnings as errors)

Zen C has full native support for Windows (x86_64). You can build using the provided batch script with GCC (MinGW):

build.bat

This will build the compiler (zc.exe). Networking, Filesystem, and Process operations are fully supported via the Platform Abstraction Layer (PAL).

Alternatively, you can use make if you have a Unix-like environment (MSYS2, Cygwin, git-bash).

Zen C can be compiled as an Actually Portable Executable (APE) using Cosmopolitan Libc. This produces a single binary (.com) that runs natively on Linux, macOS, Windows, FreeBSD, OpenBSD, and NetBSD on both x86_64 and aarch64 architectures.

Prerequisites:

• cosmocc toolchain (must be in your PATH)

Build & Install:

make ape
sudo env "PATH=$PATH" make install-ape

Artifacts:

• out/bin/zc.com: The portable Zen-C compiler. Includes the standard library embedded within the executable.
• out/bin/zc-boot.com: A self-contained bootstrap installer for setting up new Zen-C projects.

Usage:

# Run on any supported OS
./out/bin/zc.com build hello.zc -o hello

# Compile and run
zc run hello.zc

# Build executable
zc build hello.zc -o hello

# Interactive Shell
zc repl

# Documentation (Recursive)
zc doc main.zc

# Documentation (Single file, no check)
zc doc --no-recursive-doc --no-check main.zc

# Show Zen Facts
zc build hello.zc --zen

You can set ZC_ROOT to specify the location of the Standard Library (standard imports like import "std/vec.zc"). This allows you to run zc from any directory.

export ZC_ROOT=/path/to/Zen-C

See the official Language Reference for more details.

Zen C includes a standard library (std) covering essential functionality.

Browse the Standard Library Documentation

Zen C features a built-in testing framework with per-test isolation, named output, and non-fatal assertions.

A test block contains a descriptive name and a body of code to execute. Tests do not require a main function to run.

test "descriptive name" {
    let a = 3;
    assert(a > 0, "a should be positive");
}

zc run my_file.zc

Output shows each test by name:

  TEST: descriptive name ... OK
  TEST: another test ... FAIL

1 test(s) failed

Use assert for critical checks that should stop the current test, and expect when you want to verify multiple conditions without short-circuiting:

test "example" {
    expect(result != null, "result should not be null");
    expect(result.code == 200, "status should be 200");
    // both run even if the first fails
}

The binary exits with the number of failed tests (0 = all passed).

Zen C provides a built-in Language Server and REPL to enhance the development experience. It is also debuggable with LLDB.

The Zen C Language Server (LSP) supports standard LSP features for editor integration, providing:

• Go to Definition
• Find References
• Hover Information
• Completion (Function/Struct names, Dot-completion for methods/fields)
• Document Symbols (Outline)
• Signature Help
• Diagnostics (Syntax/Semantic errors)

To start the language server (typically configured in your editor's LSP settings):

zc lsp

It communicates via standard I/O (JSON-RPC 2.0).

The Read-Eval-Print Loop allows you to experiment with Zen C code interactively using modern In-Process JIT Compilation (powered by LibTCC).

zc repl

• JIT Execution: Code is compiled in-memory and executed directly within the REPL process for lightning-fast feedback.

• Interactive Coding: Type expressions or statements for immediate evaluation.

• Persistent History: Commands are saved to ~/.zprep_history.

• Startup Script: Auto-loads commands from ~/.zprep_init.zc.

Zen C includes a built-in Language Server for editor integration.

• Installation & Setup Guide
• Supported Editors: VS Code, Neovim, Vim (zenc.vim), Zed, and any LSP-capable editor.

Use zc lsp to start the server.

Zen C programs can be debugged using standard C debuggers like LLDB or GDB.

For the best experience in VS Code, install the official Zen C extension. For debugging, you can use the C/C++ (by Microsoft) or CodeLLDB extension.

Add these configurations to your .vscode directory to enable one-click debugging:

tasks.json (Build Task):

{
    "label": "Zen C: Build Debug",
    "type": "shell",
    "command": "zc",
    "args": [ "${file}", "-g", "-o", "${fileDirname}/app", "-O0" ],
    "group": { "kind": "build", "isDefault": true }
}

launch.json (Debugger):

{
    "name": "Zen C: Debug (LLDB)",
    "type": "lldb",
    "request": "launch",
    "program": "${fileDirname}/app",
    "preLaunchTask": "Zen C: Build Debug"
}

Zen C is designed to work with most C11 compilers. Some features rely on GNU C extensions, but these often work in other compilers. Use the --cc flag to switch backends.

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

The Zen C test suite includes verification against MISRA C:2012 guidelines.

Zig's zig cc command provides a drop-in replacement for GCC/Clang with excellent cross-compilation support. To use 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

Zen C supports multiple output backends via the --backend flag. Each backend produces a different target format:

Backend-specific options can be set with --backend-opt:

# Pretty-print JSON output
zc transpile file.zc --backend json --backend-opt pretty

# Show full raw content (no truncation)
zc transpile file.zc --backend lisp --backend-opt full-content

# OR use convenience aliases:
zc transpile file.zc --backend json --json-pretty
zc transpile file.zc --backend lisp --backend-full-content

All backend options are self-documented — unknown -- flags are checked against registered backend aliases automatically.

Zen C can generate C++-compatible code with the --backend cpp flag (--cpp for short), allowing seamless integration with C++ libraries.

# Direct compilation with g++
zc app.zc --backend cpp

# Or transpile for manual build
zc transpile app.zc --backend cpp
g++ out.cpp my_cpp_lib.o -o app

Include C++ headers and use raw blocks for C++ code:

include <vector>
include <iostream>

raw {
    std::vector<int> make_vec(int a, int b) {
        return {a, b};
    }
}

fn main() {
    let v = make_vec(1, 2);
    raw { std::cout << "Size: " << v.size() << std::endl; }
}

Zen C supports GPU programming by transpiling to CUDA C++ via the --backend cuda flag (--cuda for short). This allows you to leverage powerful C++ features (templates, constexpr) within your kernels while maintaining Zen C's ergonomic syntax.

# Direct compilation with nvcc
zc run app.zc --backend cuda

# Or transpile for manual build
zc transpile app.zc --backend cuda -o app.cu
nvcc app.cu -o app

Zen C provides a clean launch statement for invoking CUDA kernels:

launch kernel_name(args) with {
    grid: num_blocks,
    block: threads_per_block,
    shared_mem: 1024,  // Optional
    stream: my_stream   // Optional
};

This transpiles to: kernel_name<<<grid, block, shared, stream>>>(args);

Use Zen C function syntax with @global and the launch statement:

import "std/cuda.zc"

@global
fn add_kernel(a: float*, b: float*, c: float*, n: int) {
    let i = thread_id();
    if i < n {
        c[i] = a[i] + b[i];
    }
}

fn main() {
    def N = 1024;
    let d_a = cuda_alloc<float>(N);
    let d_b = cuda_alloc<float>(N); 
    let d_c = cuda_alloc<float>(N);
    defer cuda_free(d_a);
    defer cuda_free(d_b);
    defer cuda_free(d_c);

    // ... init data ...
    
    launch add_kernel(d_a, d_b, d_c, N) with {
        grid: (N + 255) / 256,
        block: 256
    };
    
    cuda_sync();
}

Zen C provides a standard library for common CUDA operations to reduce raw blocks:

import "std/cuda.zc"

// Memory management
let d_ptr = cuda_alloc<float>(1024);
cuda_copy_to_device(d_ptr, h_ptr, 1024 * sizeof(float));
defer cuda_free(d_ptr);

// Synchronization
cuda_sync();

// Thread Indexing (use inside kernels)
let i = thread_id(); // Global index
let bid = block_id();
let tid = local_id();

Zen C supports modern C23 features when using a compatible backend compiler (GCC 14+, Clang 14+, TCC (partial)).

• auto: Zen C automatically maps type inference to standard C23 auto if __STDC_VERSION__ >= 202300L.
• _BitInt(N): Use iN and uN types (e.g., i256, u12, i24) to access C23 arbitrary-width integers.

Zen C can compile to Objective-C (.m) using the --backend objc flag (--objc for short), allowing you to use Objective-C frameworks (like Cocoa/Foundation) and syntax.

# Compile with clang (or gcc/gnustep)
zc app.zc --backend objc --cc clang

Use include for headers and raw blocks for Objective-C syntax (@interface, [...], @"").

//> macos: framework: Foundation
//> linux: cflags: -fconstant-string-class=NSConstantString -D_NATIVE_OBJC_EXCEPTIONS
//> linux: link: -lgnustep-base -lobjc

include <Foundation/Foundation.h>

fn main() {
    raw {
        NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
        NSLog(@"Hello from Objective-C!");
        [pool drain];
    }
    println "Zen C works too!";
}

Zen C can be used as a C library via the public headers in src/public/*.h. These headers compile without -DZC_ALLOW_INTERNAL and provide a stable API for embedding the compiler in your own tools:

#include <zc_core.h>
#include <zc_driver.h>
#include <zc_diag.h>

int main(void) {
    ZenCompiler compiler = {0};
    compiler.config.input_file = "source.zc";
    return driver_run(&compiler);
}

Compile with:

cc -I src/public -I src -I src/utils my_tool.c -o my_tool

After install (make install):

cc -I /usr/local/include/zenc my_tool.c -o my_tool

The public API covers:

• zc_core.h — CompilerConfig, ZenCompiler, ASTNode, Type types, parser entry points, type introspection helpers
• zc_driver.h — driver_run(), driver_compile() (full pipeline orchestration)
• zc_codegen.h — codegen_node(), emit_preamble(), format_expression_as_c()
• zc_analysis.h — check_program(), check_moves_only(), resolve_alias()
• zc_diag.h — zerror_at(), zwarn_at(), zpanic_at(), diagnostic reporting
• zc_utils.h — Emitter (output buffer), load_file(), z_resolve_path()

Install with sudo make install to deploy headers, the binary, man pages, and standard library.

We welcome contributions! Whether it's fixing bugs, adding documentation, or proposing new features.

Please see CONTRIBUTING.md for detailed guidelines on how to contribute, run tests, and submit pull requests.

For security reporting instructions, please see SECURITY.md.

This project uses third-party libraries. Full license texts can be found in the LICENSES/ directory.

• cJSON (MIT License): Used for JSON parsing and generation in the Language Server.
• zc-ape (MIT License): The original Actually Portable Executable port of Zen-C by Eugene Olonov.
• Cosmopolitan Libc (ISC License): The foundational library that makes APE possible.
• TRE (BSD License): Used for the regular expression engine in the standard library.
• zenc.vim (MIT License): The official Vim/Neovim plugin, primarily authored by davidscholberg.
• TinyCC (LGPL License): The foundational JIT engine used for the high-performance REPL evaluation.