Added REPL, Scanner and Compiler

Basic scanner works already. Compiler does noting yet

src/main.rs

@@ -1,17 +1,92 @@
 mod vm;
 
 use colored::Colorize;
+use std::io::{Read, Write};
+use std::process::exit;
+
+use std::fs::File;
+use std::{env, io};
 
 use crate::vm::block::{Block, OpCode};
 
 use crate::vm::vm::VirtualMachine;
 
 fn main() {
+    print_tagline();
+
+    let args: Vec<String> = env::args().collect();
+
+    if args.len() == 1 {
+        run_repl();
+    } else if args.len() == 2 {
+        run_file(&args[1]);
+    } else {
+        exit(64);
+    }
+}
+
+fn print_tagline() {
     println!(
         "Hi, this is {} - a toy language you didn't wait for.",
         "neon".truecolor(240, 0, 255).bold()
     );
+}
+
+fn run_repl() {
+    println!("Running REPL");
+
+    let mut vm = VirtualMachine::new();
+
+    loop {
+        print_prompt();
+
+        let line = read_line();
+
+        vm.interpret(line);
+
+        println!();
+    }
+}
+
+fn read_line() -> String {
+    let mut input = String::new();
+    io::stdin()
+        .read_line(&mut input)
+        .expect("Failed to read line");
+    String::from(input.trim())
+}
+
+fn print_prompt() {
+    print!("> ");
+    io::stdout().flush().unwrap();
+}
+
+fn run_file(path: &String) {
+    println!("Running file: {} ", path);
+    println!();
+
+    let source = read_file(path);
+    let mut vm = VirtualMachine::new();
+
+    let result: vm::vm::Result = vm.interpret(source);
+    match result {
+        vm::vm::Result::Ok => return,
+        vm::vm::Result::CompileError => exit(65),
+        vm::vm::Result::RuntimeError => exit(70),
+    }
+}
+
+fn read_file(path: &str) -> String {
+    let mut file = File::open(path).expect(format!("Failed to open the file {}", path).as_str());
+
+    // Read the file contents into a string
+    let mut contents = String::new();
+    file.read_to_string(&mut contents)
+        .expect(format!("Failed to read the file {}", path).as_str());
+    contents
+}
 
+fn write_block() -> Block {
     let mut block = Block::new("ZeBlock");
 
     block.write_constant(1234.56, 2);
@@ -22,6 +97,5 @@ fn main() {
     block.write_op_code(OpCode::Multiply, 6);
     block.write_op_code(OpCode::Return, 8);
 
-    let mut vm = VirtualMachine::new(block);
-    vm.interpret();
+    block
 }

src/neon.n

@@ -0,0 +1,9 @@
+var x = 123;
+
+if (x == 123 and x > 3) {
+    print("x is 123");
+}
+
+fun test() {
+
+}

src/vm/compiler.rs

@@ -0,0 +1,12 @@
+use crate::vm::scanner::Scanner;
+
+pub(crate) struct Compiler {}
+
+impl Compiler {
+    pub(super) fn compile(&self, source: String) {
+        let scanner = Scanner::new(source);
+        for token in scanner {
+            println!("{:?}", token);
+        }
+    }
+}

src/vm/mod.rs

@@ -1,2 +1,4 @@
 pub mod block;
+mod compiler;
+mod scanner;
 pub mod vm;