ruchy 4.2.1

// Simple Ruchy lexer - proof of concept for self-hosting
// This demonstrates that Ruchy can implement its own lexer

// Define a simple token type using an enum
enum Token {
    Number,
    Plus,
    Minus,
    Star,
    Slash,
    LeftParen,
    RightParen,
    Eof
}

// Tokenize a simple arithmetic expression
fun tokenize_char(ch: str) -> Token {
    match ch {
        "+" => Token::Plus,
        "-" => Token::Minus,
        "*" => Token::Star,
        "/" => Token::Slash,
        "(" => Token::LeftParen,
        ")" => Token::RightParen,
        _ => Token::Number
    }
}

// Process a simple string
fun tokenize_string(input: str) -> [Token] {
    let tokens = [];
    let chars = input.split("");
    
    for ch in chars {
        if ch != " " && ch != "" {
            let token = tokenize_char(ch);
            tokens.push(token);
        }
    }
    
    tokens.push(Token::Eof);
    tokens
}

// Display token
fun display_token(token: Token) -> str {
    match token {
        Token::Number => "Number",
        Token::Plus => "Plus",
        Token::Minus => "Minus", 
        Token::Star => "Star",
        Token::Slash => "Slash",
        Token::LeftParen => "LeftParen",
        Token::RightParen => "RightParen",
        Token::Eof => "EOF"
    }
}

// Main function to test the lexer
fun main() {
    let input = "1 + 2 * 3";
    println("Input: {input}");
    
    let tokens = tokenize_string(input);
    
    println("Tokens:");
    for token in tokens {
        let name = display_token(token);
        println("  {name}");
    }
}