The χ (chi) Programming Language

An imperative programming language that transpiles to C. It features overloadable functions, structs, methods, a module system, extern functions, basic type inference, immutable/mutable references, auto referencing and dereferencing.

Getting Started

The examples/ folder shows the basic syntax and semantics of the language.

Example program (from examples/recursion.chi):

extern "<stdio.h>" {
    def printf(fmt_str: !char, ...)
}

def fib(n: int) -> int {
    if n < 2 {
        return 1
    }
    return fib(n-1) + fib(n-2)
}

def main() {
    printf("fib(9) = %i\n", fib(9))
}

Try running it:

cargo run -- examples/recursion.chi

To compile and run a program, simply pass it as the first argument to the compiler :

cargo run -- <program.chi>

The generated C code and the compiled executable should be located in the generated/ folder in the current directory. Executable generation is only supported on Linux (and perhaps MacOS, untested), though Chi generates a single C file, so manual compilation shouldn't be an issue.

Tests

cargo test compiles and runs every examples in the examples/ folder and check if any of them failed to compile or run.

All examples should compile and return 0.

Architecture

• src/main.rs: entry point

• src/lib.rs: library root, backbone of the compiler pipeline

• src/lexer.rs: lexer

• src/parser.rs: recursive descent parser

• src/ast.rs: untyped AST types

• src/analysis/mod.rs: multi-pass module declaration analysis, function/statement/expression typing, method resolution

• src/analysis/resources.rs: resource types, resource resolution routines, overload resolution

• src/analysis/expression.rs: typed AST types, lvalue checking, type coercion of arguments

• src/analysis/builtins.rs: builtin types and operator definitions

• src/transpiler.rs: transpiles a typed module into a C source file.

• src/compilation.rs: (Linux only) calls clang to compile the generated the generated C file.

References

• https://craftinginterpreters.com/parsing-expressions.html
• https://github.com/gchatelet/gcc_cpp_mangling_documentation