Non-enum opcodes

- Gt: Greater than
- Ge: Greater or equal
- Lt: Less than
- Le: Less or equal

README.md

@@ -2,6 +2,56 @@
 
 ## High level Components
 
-- [ ] Lexer: Transforms text into Tokens
+- [x] Lexer: Transforms text into Tokens
-- [ ] Parser: Transforms Tokens into Abstract Syntax Tree
+- [x] Parser: Transforms Tokens into Abstract Syntax Tree
-- [ ] Interpreter (tree-walk-interpreter): Walks the tree and evaluates the expressions / statements
+- [x] Interpreter (tree-walk-interpreter): Walks the tree and evaluates the expressions / statements
+- [ ] Abstract Syntax Tree Optimizer
+
+## Language features
+
+- [x] Math expressions
+  - [x] Unary operators
+    - [x] Negate `-X`
+  - [x] Parentheses `(X+Y)*Z`
+  - [x] Logical boolean operators
+- [x] Variables
+  - [x] Declaration
+  - [x] Assignment
+- [x] While loop `while X { ... }`
+- [x] If else statement `if X { ... } else { ... }`
+  - [x] If Statement
+  - [x] Else statement
+- [ ] Line comments `//`
+- [x] Strings
+- [x] For loops `for X; Y; Z { ... }`
+- [ ] IO Intrinsics
+  - [x] Print
+  - [ ] ReadLine
+
+## Grammar
+### Expressions
+```
+LITERAL = I64 | Str
+expr_primary = LITERAL | IDENT | "(" expr ")" | "-" expr_primary
+expr_mul = expr_primary (("*" | "/" | "%") expr_primary)*
+expr_add = expr_mul (("+" | "-") expr_mul)*
+expr_shift = expr_add ((">>" | "<<") expr_add)*
+expr_rel = expr_shift ((">" | ">=" | "<" | "<=") expr_shift)*
+expr_equ = expr_rel (("==" | "!=") expr_rel)*
+expr_band = expr_equ ("&" expr_equ)*
+expr_bxor = expr_band ("^" expr_band)*
+expr_bor = expr_bxor ("|" expr_bxor)*
+expr = expr_bor
+```
+
+## Statements
+```
+stmt_expr = expr
+stmt_let = "let" IDENT "=" expr
+stmt_while = "while" expr "{" (stmt)* "}"
+stmt_for = "for" stmt_let ";" expr ";" expr "{" (stmt)* "}"
+stmt_if = "if" expr "{" (stmt)* "}" ( "else" "{" (stmt)* "}" )
+stmt_dbgprint = "$$" expr
+stmt_print = "$" expr
+stmt = stmt_expr | stmt_let | stmt_while | stmt_for | stmt_if | stmt_dbgprint | stmt_print
+```

src/ast.rs

@@ -0,0 +1,104 @@
+use std::rc::Rc;
+
+/// Types for binary operators
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub enum BinOpType {
+    /// Addition
+    Add,
+
+    /// Subtraction
+    Sub,
+
+    /// Multiplication
+    Mul,
+
+    /// Divide
+    Div,
+
+    /// Modulo
+    Mod,
+
+    /// Bitwise OR (inclusive or)
+    BOr,
+
+    /// Bitwise And
+    BAnd,
+
+    /// Bitwise Xor (exclusive or)
+    BXor,
+
+    /// Shift Left
+    Shl,
+
+    /// Shift Right
+    Shr,
+
+    /// Check equality
+    Equ,
+
+    /// Check unequality
+    Neq,
+
+    /// Check greater than
+    Gt,
+
+    /// Check greater or equal
+    Ge,
+
+    /// Check less than
+    Lt,
+
+    /// Check less or equal
+    Le,
+
+    /// Assign to a variable
+    Assign,
+}
+
+/// Types for unary operators
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub enum UnOpType {
+    /// Negation
+    Neg,
+}
+
+/// A full program abstract syntax tree. This consists of zero or more statements that represents 
+/// a program.
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub struct Ast {
+    pub prog: Vec<Stmt>,
+}
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub enum Stmt {
+    /// Just a simple expression. This might be an assignment, a function call or a calculation.
+    Expr(Expr),
+    /// A variable declaration and assignment. (variable name, assigned value)
+    Let(String, Expr),
+    /// A while loop consisting of a condition and a body. (condition, body)
+    While(Expr, Ast),
+    /// A for loop consisting of an initialization declaration, a condition, an advancement and a 
+    /// body. ((variable name, initial value), condition, advancement, body)
+    For((String, Expr), Expr, Expr, Ast),
+    /// If statement consisting of a condition, a true_body and a false_body. 
+    /// (condition, true_body, false_body)
+    If(Expr, Ast, Ast),
+    /// Debug print the value of an expression (show the internal type together with the value)
+    DbgPrint(Expr),
+    /// Print the value of an expression
+    Print(Expr),
+}
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub enum Expr {
+    /// Integer literal (64-bit)
+    I64(i64),
+    /// String literal
+    Str(Rc<String>),
+    /// Identifier (variable name)
+    Ident(String),
+    /// Binary operation. Consists of type, left hand side and right hand side
+    BinOp(BinOpType, Box<Expr>, Box<Expr>),
+    /// Unary operation. Consists of type and the value that is operated on
+    UnOp(UnOpType, Box<Expr>),
+}

src/bytecode.rs

@@ -0,0 +1,197 @@
+use std::collections::HashMap;
+
+use crate::ast::{Ast, Expr, Stmt, BinOpType};
+
+pub mod op {
+    type OpSize = u32;
+
+    pub const PUSH: OpSize = 0;
+    pub const POP: OpSize = 1;
+    pub const LOAD: OpSize = 2;
+    pub const STORE: OpSize = 3;
+    pub const ADD: OpSize = 4;
+    pub const SUB: OpSize = 5;
+    pub const MUL: OpSize = 6;
+    pub const DIV: OpSize = 7;
+    pub const MOD: OpSize = 8;           
+    pub const BOR: OpSize = 9;
+    pub const BAND: OpSize = 10;
+    pub const BXOR: OpSize = 11;
+    pub const SHL: OpSize = 12;
+    pub const SHR: OpSize = 13;
+    pub const EQ: OpSize = 14;
+    pub const NEQ: OpSize = 15;
+    pub const GT: OpSize = 16;
+    pub const GE: OpSize = 17;
+    pub const LT: OpSize = 18;
+    pub const LE: OpSize = 19;
+    pub const JUMP: OpSize = 20;
+    pub const JUMP_TRUE: OpSize = 21;
+    pub const JUMP_FALSE: OpSize = 22;
+    pub const PRINT: OpSize = 23;
+    pub const DBG_PRINT: OpSize = 24;
+}
+
+#[derive(Debug, Default)]
+pub struct Compiler {
+    ops: Vec<u32>,
+    global_vars: HashMap<String, u16>,
+}
+
+impl Compiler {
+    pub fn new() -> Self {
+        Compiler::default()
+    }
+
+    pub fn compile(&mut self, ast: &Ast) {
+        for stmt in &ast.prog {
+            match stmt {
+                Stmt::Expr(expr) => {
+                    self.compile_expr(expr);
+                    self.ops.push(op::POP);
+                }
+                Stmt::Let(name, rhs) => {
+                    let id = self.global_vars.len() as u16;
+                    self.global_vars.insert(name.clone(), id);
+
+                    self.compile_expr(rhs);
+                    self.gen_store(id);
+                }
+                Stmt::While(cond, body) => {
+                    self.compile_expr(cond);
+
+                    self.ops.push(op::JUMP_FALSE);
+                    let idx_jmp = self.ops.len();
+                    self.gen_i64(0);
+                    
+                    let idx_start = self.ops.len();
+
+                    self.compile(body);
+
+                    // check condition before loop jump
+                    self.compile_expr(cond);
+
+                    self.ops.push(op::JUMP_TRUE);
+                    self.gen_i64(idx_start as i64);
+
+                    self.overwrite_i64(idx_jmp, self.ops.len() as i64);
+                }
+                Stmt::For(_, _, _, _) => todo!(),
+                Stmt::If(cond, if_block, else_block) => {
+                    self.compile_expr(cond);
+
+                    self.ops.push(op::JUMP_FALSE);
+                    let idx_if = self.ops.len();
+                    self.gen_i64(0);
+
+                    self.compile(if_block);
+
+                    self.ops.push(op::JUMP);
+                    let idx_else = self.ops.len();
+                    self.gen_i64(0);
+
+                    self.overwrite_i64(idx_if, self.ops.len() as i64);
+
+                    self.compile(else_block);
+
+                    self.overwrite_i64(idx_else, self.ops.len() as i64);
+
+                },
+                Stmt::DbgPrint(expr) => {
+                    self.compile_expr(expr);
+                    self.ops.push(op::DBG_PRINT);
+                }
+                Stmt::Print(expr) => {
+                    self.compile_expr(expr);
+                    self.ops.push(op::PRINT);
+                }
+            }
+        }
+    }
+
+    pub fn into_ops(self) -> Vec<u32> {
+        self.ops
+    }
+
+    pub fn compile_expr(&mut self, expr: &Expr) {
+        match expr {
+            Expr::I64(val) => {
+                self.ops.push(op::PUSH);
+                self.gen_i64(*val)
+            }
+            Expr::Ident(name) => {
+                match self.global_vars.get(name).copied() {
+                    Some(addr) => self.gen_load(addr),
+                    None => panic!("Variable '{}' used before declaration", name),
+                }
+            },
+            Expr::BinOp(bo, lhs, rhs) => self.compile_binop(bo, lhs, rhs),
+            Expr::UnOp(_, _) => todo!(),
+            Expr::Str(_) => todo!(),
+        }
+    }
+
+    fn compile_binop(&mut self, bo: &BinOpType, lhs: &Expr, rhs: &Expr) {
+
+        if matches!(bo, BinOpType::Assign) {
+            self.compile_expr(rhs);
+
+            if let Expr::Ident(name) = lhs {
+                let addr = *self.global_vars.get(name).expect("Trying to assign var before decl");
+                self.gen_store(addr);
+            } else {
+                panic!("Trying to assign value to rvalue");
+            }
+            return;
+        }
+
+        self.compile_expr(lhs);
+        self.compile_expr(rhs);
+
+        match bo {
+            BinOpType::Add => self.ops.push(op::ADD),
+            BinOpType::Sub => self.ops.push(op::SUB),
+            BinOpType::Mul => self.ops.push(op::MUL),
+            BinOpType::Div => self.ops.push(op::DIV),
+            BinOpType::Mod => self.ops.push(op::MOD),
+            BinOpType::BOr => self.ops.push(op::BOR),
+            BinOpType::BAnd => self.ops.push(op::BAND),
+            BinOpType::BXor => self.ops.push(op::BXOR),
+            BinOpType::Shl => self.ops.push(op::SHL),
+            BinOpType::Shr => self.ops.push(op::SHR),
+            BinOpType::Equ => self.ops.push(op::EQ),
+            BinOpType::Neq => self.ops.push(op::NEQ),
+            BinOpType::Gt => self.ops.push(op::GT),
+            BinOpType::Ge => self.ops.push(op::GE),
+            BinOpType::Lt => self.ops.push(op::LT),
+            BinOpType::Le => self.ops.push(op::LE),
+            BinOpType::Assign => unreachable!(),
+        }
+    }
+
+    fn gen_i64(&mut self, val: i64) {
+        self.ops.push((val & u32::MAX as i64) as u32);
+        self.ops.push((val >> 32) as u32);
+    }
+
+    fn overwrite_i64(&mut self, idx: usize, val: i64) {
+        self.ops[idx] = (val & u32::MAX as i64) as u32;
+        self.ops[idx+1] = (val >> 32) as u32;
+    }
+
+    fn gen_load(&mut self, addr: u16) {
+        self.ops.push(op::LOAD | (addr << 8) as u32);
+        // self.gen_i64(addr as i64)
+    }
+
+    fn gen_store(&mut self, addr: u16) {
+        self.ops.push(op::STORE | (addr << 8) as u32);
+        // self.gen_i64(addr as i64)
+    }
+}
+
+pub fn compile(ast: &Ast) -> Vec<u32> {
+    let mut compiler = Compiler::new();
+    compiler.compile(ast);
+    compiler.into_ops()
+}

src/interpreter.rs

@@ -1,33 +1,132 @@
-use crate::parser::{Ast, BinOpType};
+use std::{collections::HashMap, fmt::Display, rc::Rc};
+
+use crate::{
+    ast::{Ast, BinOpType, Expr, Stmt, UnOpType},
+    lexer::lex,
+    parser::parse,
+};
 
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum Value {
     I64(i64),
+    Str(Rc<String>),
 }
 
 pub struct Interpreter {
-    // Runtime storage, for example variables ...
+    /// The variable table maps all variables by their names to their values
+    vartable: HashMap<String, Value>,
 }
 
 impl Interpreter {
     pub fn new() -> Self {
-        Self {}
+        let vartable = HashMap::new();
+        Self { vartable }
     }
 
-    pub fn run(&mut self, prog: Ast) {
+    pub fn run_text(&mut self, code: &str, print_tokens: bool, print_ast: bool) {
-        let result = self.resolve_expr(prog);
+        let tokens = lex(code);
-
+        if print_tokens {
-        println!("Result = {:?}", result);
+            println!("Tokens: {:?}", tokens);
+        }
+        let ast = parse(tokens);
+        if print_ast {
+            println!("Ast:\n{:#?}", ast);
+        }
+        self.run(&ast);
     }
 
-    fn resolve_expr(&mut self, expr: Ast) -> Value {
+    pub fn run(&mut self, prog: &Ast) {
-        match expr {
+        for stmt in &prog.prog {
-            Ast::I64(val) => Value::I64(val),
+            match stmt {
-            Ast::BinOp(bo, lhs, rhs) => self.resolve_binop(bo, *lhs, *rhs),
+                Stmt::Expr(expr) => {
+                    self.resolve_expr(expr);
+                }
+                Stmt::DbgPrint(expr) => {
+                    let result = self.resolve_expr(expr);
+                    println!("{:?}", result);
+                }
+                Stmt::Print(expr) => {
+                    let result = self.resolve_expr(expr);
+                    print!("{}", result);
+                }
+                Stmt::Let(name, rhs) => {
+                    let result = self.resolve_expr(rhs);
+                    self.vartable.insert(name.clone(), result);
+                }
+                Stmt::For(init, condition, advance, body) => {
+                    // Execute initital let instruction
+                    let init_val = self.resolve_expr(&init.1);
+                    self.vartable.insert(init.0.clone(), init_val);
+
+                    loop {
+                        // Check condition
+                        match self.resolve_expr(condition) {
+                            Value::I64(val) if val == 0 => break,
+                            Value::I64(_) => (),
+
+                            Value::Str(text) if text.is_empty() => break,
+                            Value::Str(_) => (),
+                        }
+
+                        // Execute loop body
+                        self.run(body);
+
+                        // Execute advancement
+                        self.resolve_expr(advance);
+                    }
+                }
+                Stmt::While(condition, body) => {
+                    loop {
+                        // Check condition
+                        match self.resolve_expr(condition) {
+                            Value::I64(val) if val == 0 => break,
+                            Value::I64(_) => (),
+
+                            Value::Str(text) if text.is_empty() => break,
+                            Value::Str(_) => (),
+                        }
+
+                        // Execute loop body
+                        self.run(body);
+                    }
+                }
+                Stmt::If(condition, body_if, body_else) => {
+                    if matches!(self.resolve_expr(condition), Value::I64(0)) {
+                        self.run(body_else);
+                    } else {
+                        self.run(body_if);
+                    }
+                }
+            }
         }
     }
 
-    fn resolve_binop(&mut self, bo: BinOpType, lhs: Ast, rhs: Ast) -> Value {
+    fn resolve_expr(&mut self, expr: &Expr) -> Value {
+        match expr {
+            Expr::I64(val) => Value::I64(*val),
+            Expr::Str(name) => Value::Str(name.clone()),
+            Expr::BinOp(bo, lhs, rhs) => self.resolve_binop(bo, &lhs, &rhs),
+            Expr::UnOp(uo, val) => self.resolve_unop(uo, &val),
+            Expr::Ident(name) => match self.vartable.get(name) {
+                None => panic!("Runtime error: Use of undeclared variable '{}'", name),
+                Some(val) => val.clone(),
+            },
+        }
+    }
+
+    fn resolve_binop(&mut self, bo: &BinOpType, lhs: &Expr, rhs: &Expr) -> Value {
+        // Treat assignment separate from the other expressions
+        if matches!(bo, BinOpType::Assign) {
+            match lhs {
+                Expr::Ident(name) => {
+                    let rhs = self.resolve_expr(rhs);
+                    self.vartable.get_mut(name).map(|var| *var = rhs.clone());
+                    return rhs;
+                }
+                _ => panic!("Runtime error: Left hand side of assignment must be an identifier"),
+            }
+        }
+
         let lhs = self.resolve_expr(lhs);
         let rhs = self.resolve_expr(rhs);
 
@@ -35,36 +134,70 @@ impl Interpreter {
             (Value::I64(lhs), Value::I64(rhs)) => match bo {
                 BinOpType::Add => Value::I64(lhs + rhs),
                 BinOpType::Mul => Value::I64(lhs * rhs),
+                BinOpType::Sub => Value::I64(lhs - rhs),
+                BinOpType::Div => Value::I64(lhs / rhs),
+                BinOpType::Mod => Value::I64(lhs % rhs),
+                BinOpType::BOr => Value::I64(lhs | rhs),
+                BinOpType::BAnd => Value::I64(lhs & rhs),
+                BinOpType::BXor => Value::I64(lhs ^ rhs),
+                BinOpType::Shr => Value::I64(lhs >> rhs),
+                BinOpType::Shl => Value::I64(lhs << rhs),
+                BinOpType::Equ => Value::I64(if lhs == rhs { 1 } else { 0 }),
+                BinOpType::Neq => Value::I64(if lhs != rhs { 1 } else { 0 }),
+                BinOpType::Gt => Value::I64(if lhs > rhs { 1 } else { 0 }),
+                BinOpType::Ge => Value::I64(if lhs >= rhs { 1 } else { 0 }),
+                BinOpType::Lt => Value::I64(if lhs < rhs { 1 } else { 0 }),
+                BinOpType::Le => Value::I64(if lhs <= rhs { 1 } else { 0 }),
+                BinOpType::Assign => unreachable!(),
             },
-            // _ => panic!("Value types are not compatible"),
+            _ => panic!("Value types are not compatible"),
+        }
+    }
+
+    fn resolve_unop(&mut self, uo: &UnOpType, val: &Expr) -> Value {
+        let val = self.resolve_expr(val);
+        match val {
+            Value::I64(val) => match uo {
+                UnOpType::Neg => Value::I64(-val),
+            },
+            _ => panic!("Invalid unary operation for type"),
+        }
+    }
+}
+
+impl Display for Value {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Value::I64(val) => write!(f, "{}", val),
+            Value::Str(text) => write!(f, "{}", text),
         }
     }
 }
 
 #[cfg(test)]
 mod test {
-    use crate::parser::{Ast, BinOpType};
     use super::{Interpreter, Value};
+    use crate::ast::{BinOpType, Expr};
 
     #[test]
     fn test_interpreter_expr() {
         // Expression: 1 + 2 * 3 + 4
         // With precedence: (1 + (2 * 3)) + 4
-        let ast = Ast::BinOp(
+        let ast = Expr::BinOp(
             BinOpType::Add,
-            Ast::BinOp(
+            Expr::BinOp(
                 BinOpType::Add,
-                Ast::I64(1).into(),
+                Expr::I64(1).into(),
-                Ast::BinOp(BinOpType::Mul, Ast::I64(2).into(), Ast::I64(3).into()).into(),
+                Expr::BinOp(BinOpType::Mul, Expr::I64(2).into(), Expr::I64(3).into()).into(),
             )
             .into(),
-            Ast::I64(4).into(),
+            Expr::I64(4).into(),
         );
 
         let expected = Value::I64(11);
 
         let mut interpreter = Interpreter::new();
-        let actual = interpreter.resolve_expr(ast);
+        let actual = interpreter.resolve_expr(&ast);
 
         assert_eq!(expected, actual);
     }

src/lexer.rs

@@ -1,20 +1,11 @@
 use std::{iter::Peekable, str::Chars};
 
-use crate::parser::BinOpType;
+use crate::token::{Keyword, Literal, Token};
 
-#[derive(Debug, PartialEq, Eq)]
+/// Lex the provided code into a Token Buffer
-pub enum Token {
+pub fn lex(code: &str) -> Vec<Token> {
-    /// Integer literal (64-bit)
+    let mut lexer = Lexer::new(code);
-    I64(i64),
+    lexer.lex()
-
-    /// Plus (+)
-    Add,
-
-    /// Asterisk (*)
-    Mul,
-
-    /// End of file
-    EoF,
 }
 
 struct Lexer<'a> {
@@ -27,87 +18,218 @@ impl<'a> Lexer<'a> {
         Self { code }
     }
 
+    /// Advance to next character and return the removed char. If there is no next char, '\0'
+    /// is returned.
+    fn next(&mut self) -> char {
+        self.code.next().unwrap_or('\0')
+    }
+
+    /// Get the next character without removing it. If there is no next char, '\0' is returned.
+    fn peek(&mut self) -> char {
+        self.code.peek().copied().unwrap_or('\0')
+    }
+
     fn lex(&mut self) -> Vec<Token> {
         let mut tokens = Vec::new();
 
-        while let Some(ch) = self.next() {
+        loop {
-            match ch {
+            match self.next() {
+                // End of text
+                '\0' => break,
+
                 // Skip whitespace
-                ' ' => (),
+                ' ' | '\r' | '\n' | '\t' => (),
 
-                // Lex numbers
+                // Handle tokens that span two characters
-                '0'..='9' => {
+                '>' if matches!(self.peek(), '>') => {
-                    let mut sval = String::from(ch);
+                    self.next();
-
+                    tokens.push(Token::Shr);
-                    // Do as long as a next char exists and it is a numeric char
+                }
-                    while let Some('0'..='9') = self.peek() {
+                '<' if matches!(self.peek(), '<') => {
-                        // The next char is verified to be Some, so unwrap is safe
+                    self.next();
-                        sval.push(self.next().unwrap());
+                    tokens.push(Token::Shl);
-                    }
+                }
-
+                '=' if matches!(self.peek(), '=') => {
-                    // TODO: We only added numeric chars to the string, but the conversion could still fail
+                    self.next();
-                    tokens.push(Token::I64(sval.parse().unwrap()));
+                    tokens.push(Token::Equ);
+                }
+                '!' if matches!(self.peek(), '=') => {
+                    self.next();
+                    tokens.push(Token::Neq);
+                }
+                '<' if matches!(self.peek(), '=') => {
+                    self.next();
+                    tokens.push(Token::Le);
+                }
+                '>' if matches!(self.peek(), '=') => {
+                    self.next();
+                    tokens.push(Token::Ge);
+                }
+                '$' if matches!(self.peek(), '$') => {
+                    self.next();
+                    tokens.push(Token::DoubleDollar);
                 }
 
+                // Handle tokens that span one character
                 '+' => tokens.push(Token::Add),
+                '-' => tokens.push(Token::Sub),
                 '*' => tokens.push(Token::Mul),
+                '/' => tokens.push(Token::Div),
+                '%' => tokens.push(Token::Mod),
+                '|' => tokens.push(Token::BOr),
+                '&' => tokens.push(Token::BAnd),
+                '^' => tokens.push(Token::BXor),
+                '(' => tokens.push(Token::LParen),
+                ')' => tokens.push(Token::RParen),
+                '<' => tokens.push(Token::Lt),
+                '>' => tokens.push(Token::Gt),
+                '=' => tokens.push(Token::Assign),
+                ';' => tokens.push(Token::Semicolon),
+                '{' => tokens.push(Token::LBrace),
+                '}' => tokens.push(Token::RBrace),
+                '$' => tokens.push(Token::Dollar),
 
-                //TODO: Don't panic, keep calm
+                // Handle special multicharacter tokens
-                _ => panic!("Lexer encountered unexpected char: '{}'", ch),
+
+                // Lex numbers
+                ch @ '0'..='9' => tokens.push(self.lex_number(ch)),
+
+                // Lex strings
+                '"' => tokens.push(self.lex_string()),
+
+                // Lex identifiers
+                ch @ ('a'..='z' | 'A'..='Z' | '_') => tokens.push(self.lex_ident(ch)),
+
+                // Any other character is unexpected
+                ch => panic!("Lexer encountered unexpected char: '{}'", ch),
             }
         }
 
         tokens
     }
 
-    /// Advance to next character and return the removed char
+    fn lex_number(&mut self, first_char: char) -> Token {
-    fn next(&mut self) -> Option<char> {
+        let mut sval = String::from(first_char);
-        self.code.next()
+
+        // Do as long as a next char exists and it is a numeric char
+        loop {
+            // The next char is verified to be Some, so unwrap is safe
+            match self.peek() {
+                // Underscore is a separator, so remove it but don't add to number
+                '_' => {
+                    self.next();
+                }
+                '0'..='9' => {
+                    sval.push(self.next());
+                }
+                // Next char is not a number, so stop and finish the number token
+                _ => break,
+            }
+        }
+
+        // TODO: We only added numeric chars to the string, but the conversion could still fail
+        Token::Literal(Literal::I64(sval.parse().unwrap()))
     }
 
-    /// Get the next character without removing it
+    /// Lex an identifier from the character stream. The first char has to have been consumed
-    fn peek(&mut self) -> Option<char> {
+    /// from the stream already and is passed as an argument instead.
-        self.code.peek().copied()
+    fn lex_ident(&mut self, first_char: char) -> Token {
+        let mut ident = String::from(first_char);
+
+        // Do as long as a next char exists and it is a valid ident char
+        while let 'a'..='z' | 'A'..='Z' | '_' | '0'..='9' = self.peek() {
+            // The next char is verified to be Some, so unwrap is safe
+            ident.push(self.next());
+        }
+
+        // Check if the identifier is a keyword
+        match ident.as_str() {
+            "true" => Token::Literal(Literal::I64(1)),
+            "false" => Token::Literal(Literal::I64(0)),
+            "let" => Token::Keyword(Keyword::Let),
+            "while" => Token::Keyword(Keyword::While),
+            "if" => Token::Keyword(Keyword::If),
+            "else" => Token::Keyword(Keyword::Else),
+            "for" => Token::Keyword(Keyword::For),
+
+            _ => Token::Ident(ident),
+        }
     }
-}
 
-/// Lex the provided code into a Token Buffer
+    /// Lex a string token from the character stream. This requires the initial quote '"' to be
-///
+    /// consumed before.
-/// TODO: Don't panic and implement error handling using Result
+    fn lex_string(&mut self) -> Token {
-pub fn lex(code: &str) -> Vec<Token> {
+        let mut text = String::new();
-    let mut lexer = Lexer::new(code);
-    lexer.lex()
-}
 
-impl Token {
+        let mut escape = false;
-    pub fn try_to_binop(&self) -> Option<BinOpType> {
+
-        Some(match self {
+        // Do as long as a next char exists and it is not '"'
-            Token::Add => BinOpType::Add,
+        loop {
-            Token::Mul => BinOpType::Mul,
+            if escape {
-            _ => return None,
+                escape = false;
-        })
+
+                // Escape characters
+                match self.next() {
+                    '\\' => text.push('\\'),
+                    'n' => text.push('\n'),
+                    'r' => text.push('\r'),
+                    't' => text.push('\t'),
+                    ch => panic!("Invalid string escape: '{:?}'", ch),
+                }
+            } else {
+                match self.peek() {
+                    // Doublequote '"' ends the string lexing
+                    '"' => {
+                        self.next();
+                        break;
+                    }
+                    // Backslash '\' escapes the next character
+                    '\\' => {
+                        self.next();
+                        escape = true;
+                    }
+
+                    // Reached end of text but didn't encounter closing doublequote '"'
+                    '\0' => panic!("String is never terminated (missing '\"')"),
+
+                    _ => text.push(self.next()),
+                }
+            }
+        }
+
+        Token::Literal(Literal::Str(text))
     }
 }
 
 #[cfg(test)]
 mod tests {
+    use crate::token::Literal;
+
     use super::{lex, Token};
 
     #[test]
     fn test_lexer() {
-        let code = "33   +5*2  + 4456467*2334+3";
+        let code = "33   +5*2  + 4456467*2334+3 % - / << ^ | & >>";
         let expected = vec![
-            Token::I64(33),
+            Token::Literal(Literal::I64(33)),
             Token::Add,
-            Token::I64(5),
+            Token::Literal(Literal::I64(5)),
             Token::Mul,
-            Token::I64(2),
+            Token::Literal(Literal::I64(2)),
             Token::Add,
-            Token::I64(4456467),
+            Token::Literal(Literal::I64(4456467)),
             Token::Mul,
-            Token::I64(2334),
+            Token::Literal(Literal::I64(2334)),
             Token::Add,
-            Token::I64(3),
+            Token::Literal(Literal::I64(3)),
+            Token::Mod,
+            Token::Sub,
+            Token::Div,
+            Token::Shl,
+            Token::BXor,
+            Token::BOr,
+            Token::BAnd,
+            Token::Shr,
         ];
 
         let actual = lex(code);

src/lib.rs

@@ -1,3 +1,7 @@
 pub mod lexer;
 pub mod parser;
 pub mod interpreter;
+pub mod token;
+pub mod ast;
+pub mod bytecode;
+pub mod vm;

src/main.rs

@@ -1,23 +1,63 @@
-use nek_lang::{lexer::lex, parser::parse, interpreter::Interpreter};
+use std::{env::args, io::Write};
 
+use nek_lang::{interpreter::Interpreter, lexer::lex, parser::parse, bytecode::compile, vm::Vm};
+
+#[derive(Debug, Default)]
+struct CliConfig {
+    print_tokens: bool,
+    print_ast: bool,
+    interactive: bool,
+    file: Option<String>,
+}
 
 fn main() {
+    let mut cfg = CliConfig::default();
 
-    let mut code = String::new();
+    for arg in args().skip(1) {
-
+        match arg.as_str() {
-    std::io::stdin().read_line(&mut code).unwrap();
+            "--tokens" | "-t" => cfg.print_tokens = true,
-    let code = code.trim();
+            "--ast" | "-a" => cfg.print_ast = true,
-
+            "--interactive" | "-i" => cfg.interactive = true,
-    let tokens = lex(&code);
+            file if cfg.file.is_none() => cfg.file = Some(file.to_string()),
-
+            _ => panic!("Invalid argument: '{}'", arg),
-    println!("Tokens: {:?}\n", tokens);
+        }
-
+    }
-    let ast = parse(tokens);
-
-    println!("Ast: {:#?}\n", ast);
 
     let mut interpreter = Interpreter::new();
 
-    interpreter.run(ast);
+    if let Some(file) = &cfg.file {
+        let code = std::fs::read_to_string(file).expect(&format!("File not found: '{}'", file));
+        let tokens = lex(&code);
+        let ast = parse(tokens);
 
+        let prog = compile(&ast);
+
+        // println!("{:?}", prog);
+
+        let mut vm = Vm::new(prog);
+
+        vm.run();
+
+        // interpreter.run_text(&code, cfg.print_tokens, cfg.print_ast);
+    }
+
+    if cfg.interactive || cfg.file.is_none() {
+
+        let mut code = String::new();
+
+        loop {
+            print!(">> ");
+            std::io::stdout().flush().unwrap();
+
+            code.clear();
+            std::io::stdin().read_line(&mut code).unwrap();
+            let code = code.trim();
+
+            if code == "exit" {
+                break;
+            }
+
+            interpreter.run_text(&code, cfg.print_tokens, cfg.print_ast);
+        }
+    }
 }

src/parser.rs

@@ -1,24 +1,9 @@
 use std::iter::Peekable;
 
-use crate::lexer::Token;
+use crate::{
-
+    ast::{Ast, BinOpType, Expr, Stmt, UnOpType},
-/// Types for binary operators
+    token::{Keyword, Literal, Token},
-#[derive(Debug, PartialEq, Eq, Clone)]
+};
-pub enum BinOpType {
-    /// Addition
-    Add,
-
-    /// Multiplication
-    Mul,
-}
-
-#[derive(Debug, PartialEq, Eq, Clone)]
-pub enum Ast {
-    /// Integer literal (64-bit)
-    I64(i64),
-    /// Binary operation. Consists of type, left hand side and right hand side
-    BinOp(BinOpType, Box<Ast>, Box<Ast>),
-}
 
 struct Parser<T: Iterator<Item = Token>> {
     tokens: Peekable<T>,
@@ -31,18 +16,173 @@ impl<T: Iterator<Item = Token>> Parser<T> {
         Self { tokens }
     }
 
-    fn parse(&mut self) -> Ast {
+    /// Get the next Token without removing it
-        self.parse_expr()
+    fn peek(&mut self) -> &Token {
+        self.tokens.peek().unwrap_or(&Token::EoF)
     }
 
-    fn parse_expr(&mut self) -> Ast {
+    /// Advance to next Token and return the removed Token
+    fn next(&mut self) -> Token {
+        self.tokens.next().unwrap_or(Token::EoF)
+    }
+
+    fn parse(&mut self) -> Ast {
+        let mut prog = Vec::new();
+
+        loop {
+            let stmt = match self.peek() {
+                Token::Semicolon => {
+                    self.next();
+                    continue;
+                }
+                Token::EoF => break,
+                Token::RBrace => break,
+
+                Token::Keyword(keyword) => match keyword {
+                    Keyword::Let => self.parse_let_stmt(),
+                    Keyword::While => self.parse_while(),
+                    Keyword::If => self.parse_if(),
+                    Keyword::For => self.parse_for(),
+                    Keyword::Else => panic!("Unexpected else keyword"),
+                },
+
+                Token::Dollar => {
+                    self.next();
+                    Stmt::Print(self.parse_expr())
+                }
+                Token::DoubleDollar => {
+                    self.next();
+                    Stmt::DbgPrint(self.parse_expr())
+                }
+                // By default try to parse an expression
+                _ => Stmt::Expr(self.parse_expr()),
+            };
+
+            prog.push(stmt);
+        }
+
+        Ast { prog }
+    }
+
+    fn parse_for(&mut self) -> Stmt {
+        if !matches!(self.next(), Token::Keyword(Keyword::For)) {
+            panic!("Error parsing for: Expected for token");
+        }
+
+        let init = match self.parse_let_stmt() {
+            Stmt::Let(name, rhs) => (name, rhs),
+            _ => unreachable!(),
+        };
+
+        if !matches!(self.next(), Token::Semicolon) {
+            panic!("Error parsing for: Expected semicolon token");
+        }
+
+        let condition = self.parse_expr();
+
+        if !matches!(self.next(), Token::Semicolon) {
+            panic!("Error parsing for: Expected semicolon token");
+        }
+
+        let advance = self.parse_expr();
+
+        if !matches!(self.next(), Token::LBrace) {
+            panic!("Error parsing for: Expected '{{' token");
+        }
+
+        let body = self.parse();
+
+        if !matches!(self.next(), Token::RBrace) {
+            panic!("Error parsing for: Expected '}}' token");
+        }
+
+        Stmt::For(init, condition, advance, body)
+    }
+
+    fn parse_if(&mut self) -> Stmt {
+        if !matches!(self.next(), Token::Keyword(Keyword::If)) {
+            panic!("Error parsing if: Expected if token");
+        }
+
+        let condition = self.parse_expr();
+
+        if !matches!(self.next(), Token::LBrace) {
+            panic!("Error parsing if: Expected '{{' token");
+        }
+
+        let body_if = self.parse();
+
+        if !matches!(self.next(), Token::RBrace) {
+            panic!("Error parsing if: Expected '}}' token");
+        }
+
+        let mut body_else = Ast { prog: Vec::new() };
+
+        if matches!(self.peek(), Token::Keyword(Keyword::Else)) {
+            self.next();
+
+            if !matches!(self.next(), Token::LBrace) {
+                panic!("Error parsing else: Expected '{{' token");
+            }
+
+            body_else = self.parse();
+
+            if !matches!(self.next(), Token::RBrace) {
+                panic!("Error parsing else: Expected '}}' token");
+            }
+        }
+
+        Stmt::If(condition, body_if, body_else)
+    }
+
+    fn parse_while(&mut self) -> Stmt {
+        if !matches!(self.next(), Token::Keyword(Keyword::While)) {
+            panic!("Error parsing while: Expected while token");
+        }
+
+        let condition = self.parse_expr();
+
+        if !matches!(self.next(), Token::LBrace) {
+            panic!("Error parsing while: Expected '{{' token");
+        }
+
+        let body = self.parse();
+
+        if !matches!(self.next(), Token::RBrace) {
+            panic!("Error parsing while: Expected '}}' token");
+        }
+
+        Stmt::While(condition, body)
+    }
+
+    fn parse_let_stmt(&mut self) -> Stmt {
+        if !matches!(self.next(), Token::Keyword(Keyword::Let)) {
+            panic!("Error parsing let: Expected let token");
+        }
+
+        let name = match self.next() {
+            Token::Ident(name) => name,
+            _ => panic!("Error parsing let: Expected identifier after let"),
+        };
+
+        if !matches!(self.next(), Token::Assign) {
+            panic!("Error parsing let: Expected assignment token");
+        }
+
+        let rhs = self.parse_expr();
+
+        Stmt::Let(name, rhs)
+    }
+
+    fn parse_expr(&mut self) -> Expr {
         let lhs = self.parse_primary();
         self.parse_expr_precedence(lhs, 0)
     }
 
     /// Parse binary expressions with a precedence equal to or higher than min_prec
-    fn parse_expr_precedence(&mut self, mut lhs: Ast, min_prec: u8) -> Ast {
+    fn parse_expr_precedence(&mut self, mut lhs: Expr, min_prec: u8) -> Expr {
         while let Some(binop) = &self.peek().try_to_binop() {
+            // Stop if the next operator has a lower binding power
             if !(binop.precedence() >= min_prec) {
                 break;
             }
@@ -61,30 +201,40 @@ impl<T: Iterator<Item = Token>> Parser<T> {
                 rhs = self.parse_expr_precedence(rhs, binop.precedence() + 1);
             }
 
-            lhs = Ast::BinOp(binop, lhs.into(), rhs.into());
+            lhs = Expr::BinOp(binop, lhs.into(), rhs.into());
         }
 
         lhs
     }
 
     /// Parse a primary expression (for now only number)
-    fn parse_primary(&mut self) -> Ast {
+    fn parse_primary(&mut self) -> Expr {
         match self.next() {
-            Token::I64(val) => Ast::I64(val),
+            Token::Literal(Literal::I64(val)) => Expr::I64(val),
+
+            Token::Literal(Literal::Str(text)) => Expr::Str(text.into()),
+
+            Token::Ident(name) => Expr::Ident(name),
+
+            Token::LParen => {
+                // The tokens was an opening parenthesis, so parse a full expression again as the
+                // expression inside the parentheses `"(" expr ")"`
+                let inner = self.parse_expr();
+
+                // If there is no closing parenthesis after the expression, it is a syntax error
+                if !matches!(self.next(), Token::RParen) {
+                    panic!("Error parsing primary expr: Missing closing parenthesis ')'");
+                }
+
+                inner
+            }
+
+            Token::Sub => Expr::UnOp(UnOpType::Neg, self.parse_primary().into()),
 
             tok => panic!("Error parsing primary expr: Unexpected Token '{:?}'", tok),
         }
     }
 
-    /// Get the next Token without removing it
-    fn peek(&mut self) -> &Token {
-        self.tokens.peek().unwrap_or(&Token::EoF)
-    }
-
-    /// Advance to next Token and return the removed Token
-    fn next(&mut self) -> Token {
-        self.tokens.next().unwrap_or(Token::EoF)
-    }
 }
 
 pub fn parse<T: Iterator<Item = Token>, A: IntoIterator<IntoIter = T>>(tokens: A) -> Ast {
@@ -95,44 +245,62 @@ pub fn parse<T: Iterator<Item = Token>, A: IntoIterator<IntoIter = T>>(tokens: A
 impl BinOpType {
     /// Get the precedence for a binary operator. Higher value means the OP is stronger binding.
     /// For example Multiplication is stronger than addition, so Mul has higher precedence than Add.
+    ///
+    /// The operator precedences are derived from the C language operator precedences. While not all
+    /// C operators are included or the exact same, the precedence oder is the same.
+    /// See: https://en.cppreference.com/w/c/language/operator_precedence
     fn precedence(&self) -> u8 {
         match self {
-            BinOpType::Add => 0,
+            BinOpType::Assign => 0,
-            BinOpType::Mul => 1,
+            BinOpType::BOr => 1,
+            BinOpType::BXor => 2,
+            BinOpType::BAnd => 3,
+            BinOpType::Equ | BinOpType::Neq => 4,
+            BinOpType::Gt | BinOpType::Ge | BinOpType::Lt | BinOpType::Le => 5,
+            BinOpType::Shl | BinOpType::Shr => 6,
+            BinOpType::Add | BinOpType::Sub => 7,
+            BinOpType::Mul | BinOpType::Div | BinOpType::Mod => 8,
         }
     }
 }
 
 #[cfg(test)]
 mod tests {
-    use super::{parse, Ast, BinOpType};
+    use super::{parse, BinOpType, Expr};
-    use crate::lexer::Token;
+    use crate::{
+        parser::{Ast, Stmt},
+        token::{Literal, Token},
+    };
 
     #[test]
     fn test_parser() {
         // Expression: 1 + 2 * 3 + 4
         // With precedence: (1 + (2 * 3)) + 4
         let tokens = [
-            Token::I64(1),
+            Token::Literal(Literal::I64(1)),
             Token::Add,
-            Token::I64(2),
+            Token::Literal(Literal::I64(2)),
             Token::Mul,
-            Token::I64(3),
+            Token::Literal(Literal::I64(3)),
-            Token::Add,
+            Token::Sub,
-            Token::I64(4),
+            Token::Literal(Literal::I64(4)),
         ];
 
-        let expected = Ast::BinOp(
+        let expected = Expr::BinOp(
-            BinOpType::Add,
+            BinOpType::Sub,
-            Ast::BinOp(
+            Expr::BinOp(
                 BinOpType::Add,
-                Ast::I64(1).into(),
+                Expr::I64(1).into(),
-                Ast::BinOp(BinOpType::Mul, Ast::I64(2).into(), Ast::I64(3).into()).into(),
+                Expr::BinOp(BinOpType::Mul, Expr::I64(2).into(), Expr::I64(3).into()).into(),
             )
             .into(),
-            Ast::I64(4).into(),
+            Expr::I64(4).into(),
         );
 
+        let expected = Ast {
+            prog: vec![Stmt::Expr(expected)],
+        };
+
         let actual = parse(tokens);
         assert_eq!(expected, actual);
     }

src/token.rs

@@ -0,0 +1,147 @@
+use crate::ast::BinOpType;
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum Literal {
+    /// Integer literal (64-bit)
+    I64(i64),
+
+    /// String literal ("Some string")
+    Str(String),
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum Keyword {
+    /// Let identifier (let)
+    Let,
+
+    /// While (while)
+    While,
+
+    /// For (for)
+    For,
+
+    /// If (if)
+    If,
+
+    /// Else (else)
+    Else,
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum Token {
+    /// Literal values
+    Literal(Literal),
+
+    /// Identifier (variable / function / ... name)
+    Ident(String),
+
+    /// Specific identifiers that have a special meaning as keywords
+    Keyword(Keyword),
+
+    /// Left parenthesis ('(')
+    LParen,
+
+    /// Right parentheses (')')
+    RParen,
+
+    /// Left brace ({)
+    LBrace,
+
+    /// Right brace (})
+    RBrace,
+
+    /// Dollar sign ($)
+    Dollar,
+
+    /// Double Dollar sign ($$)
+    DoubleDollar,
+
+    /// Assignment (single equal) (=)
+    Assign,
+
+    /// Plus (+)
+    Add,
+
+    /// Minus (-)
+    Sub,
+
+    /// Asterisk (*)
+    Mul,
+
+    /// Slash (/)
+    Div,
+
+    /// Percent (%)
+    Mod,
+
+    /// Pipe (|)
+    BOr,
+
+    /// Ampersand (&)
+    BAnd,
+
+    /// Circumflex (^)
+    BXor,
+
+    /// Shift Left (<<)
+    Shl,
+
+    /// Shift Right (>>)
+    Shr,
+
+    /// Equal sign (==)
+    Equ,
+
+    /// Not Equal sign (!=)
+    Neq,
+
+    /// Greater than (>)
+    Gt,
+
+    /// Greater or equal (>=)
+    Ge,
+
+    /// Less than (<)
+    Lt,
+
+    /// Less or equal (<=)
+    Le,
+
+    /// Semicolon (;)
+    Semicolon,
+
+    /// End of file
+    EoF,
+}
+
+impl Token {
+    pub fn try_to_binop(&self) -> Option<BinOpType> {
+        Some(match self {
+            Token::Add => BinOpType::Add,
+            Token::Sub => BinOpType::Sub,
+
+            Token::Mul => BinOpType::Mul,
+            Token::Div => BinOpType::Div,
+            Token::Mod => BinOpType::Mod,
+
+            Token::BAnd => BinOpType::BAnd,
+            Token::BOr => BinOpType::BOr,
+            Token::BXor => BinOpType::BXor,
+
+            Token::Shl => BinOpType::Shl,
+            Token::Shr => BinOpType::Shr,
+
+            Token::Equ => BinOpType::Equ,
+            Token::Neq => BinOpType::Neq,
+
+            Token::Gt => BinOpType::Gt,
+            Token::Ge => BinOpType::Ge,
+            Token::Lt => BinOpType::Lt,
+            Token::Le => BinOpType::Le,
+
+            Token::Assign => BinOpType::Assign,
+
+            _ => return None,
+        })
+    }
+}

src/vm.rs

@@ -0,0 +1,208 @@
+use crate::{bytecode::op::*, interpreter::Value};
+
+#[derive(Debug, Default)]
+pub struct Vm {
+    prog: Vec<u32>,
+    ip: usize,
+    stack: Vec<Value>,
+
+    /// This isn't actually a heap. It's actually still more of a f*cked up stack
+    heap: Vec<Value>,
+}
+
+macro_rules! binop_stack {
+    ($self:ident, $op:tt) => {
+        {
+            let rhs = $self.stack.pop().unwrap();
+            let lhs = $self.stack.last_mut().unwrap();
+            match (lhs, rhs) {
+                (Value::I64(lhs), Value::I64(rhs)) => *lhs = *lhs $op rhs,
+                _ => panic!("Invalid data for add"),
+            }
+        }
+    };
+}
+
+impl Vm {
+    pub fn new(prog: Vec<u32>) -> Self {
+        Self {
+            prog,
+            ..Default::default()
+        }
+    }
+
+    pub fn run(&mut self) {
+        while let Some(op) = self.prog.get(self.ip).copied() {
+            self.ip += 1;
+
+            match op & 0xff {
+                PUSH => {
+                    let val = self.read_i64();
+                    self.stack.push(Value::I64(val));
+                }
+                POP => {
+                    self.stack.pop();
+                }
+                LOAD => {
+                    // let addr = self.read_i64() as usize;
+                    let addr = (op >> 8) as usize;
+
+                    if let Some(val) = self.heap.get(addr) {
+                        self.stack.push(val.clone());
+                    } else {
+                        panic!("Trying to load from uninitialized heap");
+                    }
+                }
+                STORE => {
+                    let val = self
+                        .stack
+                        .pop()
+                        .expect("Trying to pop value from stack for storing");
+                    // let addr = self.read_i64() as usize;
+                    let addr = (op >> 8) as usize;
+
+                    if self.heap.len() == addr {
+                        self.heap.push(val);
+                    } else {
+                        self.heap[addr] = val;
+                    }
+                }
+                PRINT => {
+                    let val = self
+                        .stack
+                        .pop()
+                        .expect("Trying to pop value from stack for printing");
+                    print!("{}", val);
+                }
+                DBG_PRINT => {
+                    let val = self
+                        .stack
+                        .pop()
+                        .expect("Trying to pop value from stack for printing");
+                    print!("{:?}", val);
+                }
+
+                ADD => {
+                    binop_stack!(self, +);
+                    // self.stack.push(Value::I64(vals.0 + vals.1))
+                }
+                SUB => {
+                    binop_stack!(self, -);
+                    // let vals = self.pop2_i64();
+                    // self.stack.push(Value::I64(vals.0 - vals.1))
+                }
+                MUL => {
+                    binop_stack!(self, *);
+                    // let vals = self.pop2_i64();
+                    // self.stack.push(Value::I64(vals.0 * vals.1))
+                }
+                DIV => {
+                    binop_stack!(self, /);
+                    // let vals = self.pop2_i64();
+                    // self.stack.push(Value::I64(vals.0 / vals.1))
+                }
+                MOD => {
+                    binop_stack!(self, %);
+                    // let vals = self.pop2_i64();
+                    // self.stack.push(Value::I64(vals.0 % vals.1))
+                }
+                EQ => {
+                    let vals = self.pop2_i64();
+                    self.stack
+                        .push(Value::I64(if vals.0 == vals.1 { 1 } else { 0 }))
+                }
+                NEQ => {
+                    let vals = self.pop2_i64();
+                    self.stack
+                        .push(Value::I64(if vals.0 != vals.1 { 1 } else { 0 }))
+                }
+                GT => {
+                    let vals = self.pop2_i64();
+                    self.stack
+                        .push(Value::I64(if vals.0 > vals.1 { 1 } else { 0 }))
+                }
+                GE => {
+                    let vals = self.pop2_i64();
+                    self.stack
+                        .push(Value::I64(if vals.0 >= vals.1 { 1 } else { 0 }))
+                }
+                LT => {
+                    let vals = self.pop2_i64();
+                    self.stack
+                        .push(Value::I64(if vals.0 < vals.1 { 1 } else { 0 }))
+                }
+                LE => {
+                    let vals = self.pop2_i64();
+                    self.stack
+                        .push(Value::I64(if vals.0 <= vals.1 { 1 } else { 0 }))
+                }
+                BOR => {
+                    let vals = self.pop2_i64();
+                    self.stack.push(Value::I64(vals.0 | vals.1))
+                }
+                BAND => {
+                    let vals = self.pop2_i64();
+                    self.stack.push(Value::I64(vals.0 & vals.1))
+                }
+                BXOR => {
+                    let vals = self.pop2_i64();
+                    self.stack.push(Value::I64(vals.0 ^ vals.1))
+                }
+                SHL => {
+                    let vals = self.pop2_i64();
+                    self.stack.push(Value::I64(vals.0 << vals.1))
+                }
+                SHR => {
+                    let vals = self.pop2_i64();
+                    self.stack.push(Value::I64(vals.0 >> vals.1))
+                }
+                JUMP => {
+                    self.ip = self.read_i64() as usize;
+                }
+                JUMP_TRUE => {
+                    let jmp_target = self.read_i64() as usize;
+                    if !matches!(self.stack.pop(), Some(Value::I64(0))) {
+                        self.ip = jmp_target;
+                    }
+                }
+                JUMP_FALSE => {
+                    let jmp_target = self.read_i64() as usize;
+                    if matches!(self.stack.pop(), Some(Value::I64(0))) {
+                        self.ip = jmp_target;
+                    }
+                }
+                _ => panic!("Invalid opcode")
+            }
+        }
+    }
+
+    fn pop2_i64(&mut self) -> (i64, i64) {
+        let rhs = self.stack.pop();
+        let lhs = self.stack.pop();
+        match (lhs, rhs) {
+            (Some(Value::I64(lhs)), Some(Value::I64(rhs))) => (lhs, rhs),
+            _ => panic!("Invalid data for add"),
+        }
+    }
+
+    fn read_i64(&mut self) -> i64 {
+        let mut val = if let Some(val) = self.prog.get(self.ip).copied() {
+            val
+        } else {
+            panic!("Expected Value as next OP")
+        } as i64;
+
+        self.ip += 1;
+
+        val |= (if let Some(val) = self.prog.get(self.ip).copied() {
+            val
+        } else {
+            panic!("Expected Value as next OP")
+        } as i64)
+            << 32;
+
+        self.ip += 1;
+
+        val
+    }
+}