🦀 cRust

cRust is a header-only experimental library that brings a small, expressive subset of Rust-style syntax into standard C and C++ through the preprocessor. It is aimed at developers who enjoy Rust’s clarity but need to remain within a C/C++ toolchain.

(and no this is not https://github.com/tsoding/Crust, this is my own project on creating simple one header rust definitions for c/c++)

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Current Features

Category	Name	Type / Expansion	Description
Keywords	fn	int	Defines a function.
	let	(empty)	alias for an variable declaration.
	mut	(empty)	alias for an mutable variable.
	brk	break	Early loop exit.
	next_iter	continue	Skip loop iteration.
	loop	for(;;)	Infinite loop.
	match	switch	Rust-style pattern matching.
	when	case	Match arm.
	_	default	Default match arm.
	pin	const	Marks a pinned/fixed pointer.
Printing / Debug	print(fmt, ...)	printf	Print without newline.
	println(fmt, ...)	printf(... + "\n")	Print with newline.
	eprint(fmt, ...)	fprintf(stderr, ...)	Print to stderr.
	panic(msg)	fprintf + exit	Abort program with message.
	unwrap(status, msg)	Panic if not OK	Rust-like unwrap for status.
Status Codes	OK	0	Success.
	ERR	1	Failure.
	SOME	0	Value exists.
	NONE	1	No value.
Types	unit	void	Unit type.
	char8	char	8-bit ASCII character.
	Boolean	bool	Boolean alias.
	i8/i16/i32/i64	int8_t /16/32/64	Signed integers.
	isize	ptrdiff_t	Signed pointer-sized integer.
	u8/u16/u32/u64	uintX_t	Unsigned integers.
	usize	size_t	Unsigned pointer-sized integer.
	f32/f64	float / double	Floating-point types.
	String	std::string	Owned string.
	str	const std::string&	String slice.
	RawPtr	void*	Raw pointer.
	ConstRawPtr	const void*	Const raw pointer.
	Ref(T)	const T*	Immutable reference.
	RefMut(T)	T*	Mutable reference.
Memory	Box(T)	T*	Heap-allocated value.
	vector(T, n)	calloc	Allocates zeroed array.
	alloc(T)	malloc	Allocates uninitialized T.
	drop(ptr)	(empty)	No-op (prevents freeing C++ RAII types).
Utilities	size_of(T)	sizeof(T)	Alias for sizeof.
	strlen(s)	s.length()	String length override for std::string.
	strcmp(s1, s2)	equality compare	std::string equality → 0/1.

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Example

#include "crust/crust.hpp"
#include <iostream>

fn main() {
    let mut i = 0;

    loop {
        if (i >= 5) {
            break;
        }

        println("Counter value: %d", i);
        i = i + 1;
    }

    return OK;
}

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Project Status

This library is experimental and relies on heavy preprocessor expansion.

Expect behavioral differences between compilers and platforms. Contributions, ideas, and tests are welcome.

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License

This project is licensed under CC BY-NC 4.0.

You may use, modify, and share the library for non-commercial purposes only, and you must keep attribution to the original author.

Copyright (c) 2025 - Kamerzystanasyt