Ferret Compiler

A modern compiler for the Ferret programming language, featuring:

• Go-style AST architecture
• Rust-style error diagnostics
• Rich type system with inference
• Compile-time error detection
• Module system

Quick Start

Run the compiler

run.bat test/simple.fer

That's it! The script uses go run to compile and run directly.

Language Features

Variables and Constants

let x := 10;              // Type inference
let y: i32 = 20;          // Explicit type
const pi := 3.14;         // Constant

Types

// Basic types
i8, i16, i32, i64         // Signed integers
u8, u16, u32, u64         // Unsigned integers
f32, f64                  // Floats
str, bool, byte           // String, boolean, byte

// Arrays
[3]i32                    // Fixed size array
[]i32                     // Dynamic array

// Optional types
i32?                      // Nullable integer

// Error types
Data ! Error              // Can return error

Structs

type Point struct {
    .x: f64,
    .y: f64
};

let p := Point{ .x = 1.0, .y = 2.0 };

Enums

type Color enum {
    Red,
    Green,
    Blue
};

let color := Color::Red;

Functions

fn add(a: i32, b: i32) -> i32 {
    return a + b;
}

Optional Types & Elvis Operator

let maybe: i32? = None;
let value := maybe ?: 42;  // Defaults to 42 if None

Error Handling

fn divide(a: i32, b: i32) -> i32 ! Error {
    if b == 0 {
        return Error{ .msg = "Division by zero" }!;
    }
    return a / b;
}

const result := divide(10, 2) catch err {
    println("Error: {}", err.msg);
} 0;  // Fallback value

Pattern Matching

when color {
    Color::Red => println("Red"),
    Color::Green => println("Green"),
    Color::Blue => println("Blue")
}

Control Flow

if x < y {
    println("x is less");
} else {
    println("x is greater or equal");
}

for i := 0; i < 10; i++ {
    println(i);
}

while condition {
    // loop body
}

Error Reporting

Ferret provides beautiful, helpful error messages:

error[T0001]: type mismatch
  --> example.fer:10:15
   |
10 | let num: i32 = "hello";
   |                ~~~~~~~ expected i32, found str
   |
  = note: type inference determined this expression has type 'str'
  = help: convert the string to an integer using the parse function

Compilation failed with 1 error(s)

Scripts

Single script for everything:

run.bat <file.fer>     # Compile a Ferret file

Set DEBUG=1 for debug output:

set DEBUG=1
run.bat test/simple.fer

Development

Running the Compiler

run.bat test/simple.fer

With Debug Output

set DEBUG=1
run.bat test/simple.fer

Running Tests

go test ./...

Status

Completed

• Go-style AST architecture
• Rust-style diagnostic system
• Semantic information system
• Type system infrastructure
• Module system design
• Lexer implementation
• Error code taxonomy
• Shared context architecture
• Multi-file compilation pipeline

🚧 In Progress

• Parser implementation
• Collector (declaration gathering)
• Symbol resolution
• Type checker
• Code generation

License

MIT License

Contributing

Contributions are welcome! Please read the documentation to understand the compiler architecture before submitting PRs.