Implement vec based scopes

- Replaced vartable hashmap with vec
- Use linear search in reverse to find the variables by name
- This is really fast with a small number of variables but tanks fast
  with more vars due to O(n) lookup times
- Implemented scopes by dropping all elements from the vartable at the
  end of a scope

Cargo.toml

@@ -4,3 +4,5 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+anyhow = "1.0.53"
+thiserror = "1.0.30"

README.md

@@ -1,38 +1,195 @@
 # NEK-Lang
 
+## Variables
+Currently all variables are global and completely unscoped. That means no matter where a variable is declared, it remains over the whole remaining runtime of the progam.
+
+All variables are currently of type `i64` (64-bit signed integer)
+
+### Declaration
+- Declare and initialize a new variable
+- Declaring a previously declared variable again is currently equivalent to an assignment
+- Declaration is needed before assignment or other usage
+- The variable name is on the left side of the `<-` operator
+- The assigned value is on the right side and can be any expression
+```
+a <- 123;
+```
+Create a new variable named `a` and assign the value `123` to it.
+
+### Assignment
+- Assigning a value to a previously declared variable
+- The variable name is on the left side of the `=` operator
+- The assigned value is on the right side and can be any expression
+```
+a = 123;
+```
+The value `123` is assigned to the variable named `a`. `a` needs to be declared before this.
+
+## Expressions
+The operator precedence is the same order as in `C` for all implemented operators. 
+Refer to the 
+[C Operator Precedence Table](https://en.cppreference.com/w/c/language/operator_precedence) 
+to see the different precedences.
+
+### General
+- Parentheses `(` and `)` can be used to modify evaluation oder just like in any other 
+programming language.
+- For example `(a + b) * c` will evaluate the addition before the multiplication, despite the multiplication having higher binding power
+
+### Mathematical Operators
+Supported mathematical operations:
+- Addition `a + b`
+- Subtraction `a - b`
+- Multiplication `a * b`
+- Division `a / b`
+- Modulo `a % b`
+- Negation `-a`
+
+### Bitwise Operators
+- And `a & b`
+- Or `a | b`
+- Xor `a ^ b`
+- Bitshift left (by `b` bits) `a << b`
+- Bitshift right (by `b` bits) `a >> b`
+- "Bit flip" (One's complement) `~a`
+
+### Logical Operators
+The logical operators evaluate the operands as `false` if they are equal to `0` and `true` if they are not equal to `0`
+- And `a && b`
+- Or `a || b`
+- Not `!a` (if `a` is equal to `0`, the result is `1`, otherwise the result is `0`)
+
+### Equality & Relational Operators
+The equality and relational operations result in `1` if the condition is evaluated as `true` and in `0` if the condition is evaluated as `false`.
+- Equality `a == b`
+- Inequality `a != b`
+- Greater than `a > b`
+- Greater or equal than `a >= b`
+- Less than `a < b`
+- Less or equal than `a <= b`
+
+## Control-Flow
+For conditions like in if or loops, every non zero value is equal to `true`, and `0` is `false`.
+
+### Loop
+- There is currently only the `loop` keyword that can act like a `while` with optional advancement (an expression that is executed after the loop body)
+- The `loop` keyword is followed by the condition (an expression) without needing parentheses
+- *Optional:* If there is a `;` after the condition, there must be another expression which is used as the advancement
+- The loops body is wrapped in braces (`{ }`) just like in C/C++
+
+```
+// Print the numbers from 0 to 9
+
+// Without advancement
+i <- 0;
+loop i < 10 {
+  print i;
+  i = i - 1;
+}
+
+// With advancement
+k <- 0;
+loop k < 10; k = k - 1 {
+  print k;
+}
+```
+
+### If / Else
+
+- The language supports `if` and an optional `else`
+- After the `if` keyword must be the deciding condition, parentheses are not needed
+- The block *if-true* block is wrapped in braces (`{ }`)
+- *Optional:* If there is an `else` after the *if-block*, there must be a following *if-false*, aka. else block
+```
+a <- 1;
+b <- 2;
+if a == b {
+  // a is equal to b
+  print 1;
+} else {
+  // a is not equal to b
+  print 0;
+}
+```
+
+## IO
+
+### Print
+Printing is implemented via the `print` keyword
+- The `print` keyword is followed by an expression, the value of which will be printed to the terminal.
+- Print currently automatically adds a linebreak
+```
+a <- 1;
+print a; // Outputs `"1\n"` to the terminal
+```
+
+## Comments
+
+### Line comments
+Line comments can be initiated by using `//`
+- Everything after `//` up to the end of the current line is ignored and not parsed
+```
+// This is a comment
+```
+
+
+# Feature Tracker
+
 ## High level Components
 
 - [x] Lexer: Transforms text into Tokens
 - [x] Parser: Transforms Tokens into Abstract Syntax Tree
 - [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] General expressions
+  - [x] Arithmetic operations
+    - [x] Addition `a + b`
+    - [x] Subtraction `a - b`
+    - [x] Multiplication `a * b`
+    - [x] Division `a / b`
+    - [x] Modulo `a % b
+    - [x] Negate `-a`
+  - [x] Parentheses `(a + b) * c`
   - [x] Logical boolean operators
+    - [x] Equal `a == b`
+    - [x] Not equal `a != b`
+    - [x] Greater than `a > b`
+    - [x] Less than `a < b`
+    - [x] Greater than or equal `a >= b`
+    - [x] Less than or equal `a <= b`
+  - [x] Logical operators
+    - [x] And `a && b`
+    - [x] Or `a || b`
+    - [x] Not `!a`
+  - [x] Bitwise operators
+    - [x] Bitwise AND `a & b`
+    - [x] Bitwise OR `a | b`
+    - [x] Bitwise XOR `a ^ b`
+    - [x] Bitwise NOT `~a`
+    - [x] Bitwise left shift `a << b`
+    - [x] Bitwise right shift `a >> b`
 - [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] Statements with semicolon & Multiline programs
+- [x] Control flow
+  - [x] While loop `while X { ... }`
+  - [x] If else statement `if X { ... } else { ... }`
+    - [x] If Statement
+    - [x] Else statement
+- [x] Line comments `//`
 - [x] Strings
-- [x] For loops `for X; Y; Z { ... }`
-- [ ] IO Intrinsics
+- [x] IO Intrinsics
   - [x] Print
-  - [ ] ReadLine
 
 ## Grammar
+
 ### Expressions
 ```
-LITERAL = I64 | Str
-expr_primary = LITERAL | IDENT | "(" expr ")" | "-" expr_primary
+LITERAL = I64_LITERAL | STR_LITERAL
+expr_primary = LITERAL | IDENT | "(" expr ")" | "-" expr_primary | "~" expr_primary
 expr_mul = expr_primary (("*" | "/" | "%") expr_primary)*
 expr_add = expr_mul (("+" | "-") expr_mul)*
 expr_shift = expr_add ((">>" | "<<") expr_add)*
@@ -41,17 +198,15 @@ 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
+expr_land = expr_bor ("&&" expr_bor)*
+expr_lor = expr_land ("||" expr_land)*
+expr = expr_lor
 ```
 
-## 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
+### Statements
 ```
+stmt_if = "if" expr "{" stmt* "}" ("else" "{" stmt* "}")?
+stmt_loop = "loop" expr (";" expr)? "{" stmt* "}"
+stmt_expr = expr ";"
+stmt = stmt_expr | stmt_loop
+```

examples/euler1.nek

@@ -0,0 +1,15 @@
+// If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. 
+// The sum of these multiples is 23.
+// Find the sum of all the multiples of 3 or 5 below 1000.
+// 
+// Correct Answer: 233168
+
+sum <- 0;
+i <- 0;
+loop i < 1_000; i = i + 1 {
+    if i % 3 == 0 | i % 5 == 0 {
+        sum = sum + i;
+    }
+}
+
+print sum;

examples/euler2.nek

@@ -0,0 +1,26 @@
+// Each new term in the Fibonacci sequence is generated by adding the previous two terms. 
+// By starting with 1 and 2, the first 10 terms will be:
+//   1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
+// By considering the terms in the Fibonacci sequence whose values do not exceed four million, 
+// find the sum of the even-valued terms.
+// 
+// Correct Answer: 4613732
+
+sum <- 0;
+
+a <- 0;
+b <- 1;
+tmp <- 0;
+
+loop a < 4_000_000 {
+    if a % 2 == 0 {
+        sum = sum + a;
+    }
+
+    tmp = a;
+    a = b;
+    b = b + tmp;
+}
+
+print sum;
+

examples/euler3.nek

@@ -0,0 +1,29 @@
+// The prime factors of 13195 are 5, 7, 13 and 29.
+// What is the largest prime factor of the number 600851475143 ?
+// 
+// Correct Answer: 6857
+
+number <- 600_851_475_143;
+result <- 0;
+
+div <- 2;
+
+loop number > 1 {
+    loop number % div == 0 {
+        if div > result {
+            result = div;
+        }
+        number = number / div;
+    }
+
+    div = div + 1;
+    if div * div > number {
+        if number > 1 & number > result {
+            result = number;
+        }
+        number = 0;
+    }
+
+}
+
+print result;

examples/euler4.nek

@@ -0,0 +1,36 @@
+// A palindromic number reads the same both ways. The largest palindrome made from the product of 
+// two 2-digit numbers is 9009 = 91 × 99.
+// Find the largest palindrome made from the product of two 3-digit numbers.
+// 
+// Correct Answer: 906609
+
+
+res <- 0;
+
+tmp <- 0;
+num <- 0;
+num_rev <- 0;
+
+i <- 100;
+k <- 100;
+loop i < 1_000; i = i + 1 {
+    k = 100;
+    loop k < 1_000; k = k + 1 {
+        num_rev = 0;
+
+        num = i * k;
+
+        tmp = num;
+
+        loop tmp {
+            num_rev = num_rev*10 + tmp % 10;
+            tmp = tmp / 10;
+        }
+
+        if num == num_rev & num > res {
+            res = num;
+        }
+    }
+}
+
+print res;

examples/euler4.py

@@ -0,0 +1,24 @@
+# A palindromic number reads the same both ways. The largest palindrome made from the product of 
+# two 2-digit numbers is 9009 = 91 × 99.
+# Find the largest palindrome made from the product of two 3-digit numbers.
+# 
+# Correct Answer: 906609
+
+
+res = 0
+
+for i in range(100, 999):
+    for k in range(100, 999):
+
+        num = i * k
+        tmp = num
+
+        num_rev = 0
+        while tmp != 0:
+            num_rev = num_rev*10 + tmp % 10
+            tmp = tmp // 10
+        
+        if num == num_rev and num > res:
+            res = num
+
+print(res)

examples/euler5.nek

@@ -0,0 +1,28 @@
+// 2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder.
+// What is the smallest positive number that is evenly divisible by all of the numbers from 1 to 20?
+// 
+// Correct Answer: 232_792_560
+
+num <- 20;
+should_continue <- 1;
+i <- 2;
+
+loop should_continue {
+    should_continue = 0;
+
+    i = 20;
+    loop i >= 2; i = i - 1 {
+        if num % i != 0 {
+            should_continue = 1;
+            
+            // break
+            i = 0;
+        }
+    }
+
+    if should_continue == 1 {
+        num = num + 20;
+    }
+}
+
+print num;

src/ast.rs

@@ -18,6 +18,24 @@ pub enum BinOpType {
     /// Modulo
     Mod,
 
+    /// Compare Equal
+    EquEqu,
+
+    /// Compare Not Equal
+    NotEqu,
+
+    /// Less than
+    Less,
+
+    /// Less than or Equal
+    LessEqu,
+
+    /// Greater than
+    Greater,
+
+    /// Greater than or Equal
+    GreaterEqu,
+
     /// Bitwise OR (inclusive or)
     BOr,
 
@@ -27,78 +45,106 @@ pub enum BinOpType {
     /// Bitwise Xor (exclusive or)
     BXor,
 
+    /// Logical And
+    LAnd,
+
+    /// Logical Or
+    LOr,
+
     /// 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 value to variable
     Assign,
+
+    /// Declare new variable with value
+    Declare,
 }
 
-/// Types for unary operators
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum UnOpType {
-    /// Negation
-    Neg,
-}
+    /// Unary Negate
+    Negate,
 
-/// 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>,
+    /// Bitwise Not
+    BNot,
+
+    /// Logical Not
+    LNot,
 }
 
 #[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 {
+pub enum Expression {
     /// Integer literal (64-bit)
     I64(i64),
     /// String literal
-    Str(Rc<String>),
-    /// Identifier (variable name)
-    Ident(String),
+    String(Rc<String>),
+    /// Variable
+    Var(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>),
-}
+    BinOp(BinOpType, Box<Expression>, Box<Expression>),
+    /// Unary operation. Consists of type and operand
+    UnOp(UnOpType, Box<Expression>),
+}
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub struct Loop {
+    /// The condition that determines if the loop should continue
+    pub condition: Expression,
+    /// This is executed after each loop to advance the condition variables
+    pub advancement: Option<Expression>,
+    /// The loop body that is executed each loop
+    pub body: Ast,
+}
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub struct If {
+    /// The condition
+    pub condition: Expression,
+    /// The body that is executed when condition is true
+    pub body_true: Ast,
+    /// The if body that is executed when the condition is false
+    pub body_false: Ast,
+}
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub enum Statement {
+    Expr(Expression),
+    Loop(Loop),
+    If(If),
+    Print(Expression),
+}
+
+#[derive(Debug, PartialEq, Eq, Clone, Default)]
+pub struct Ast {
+    pub prog: Vec<Statement>,
+}
+
+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
+
+    pub fn precedence(&self) -> u8 {
+        match self {
+            BinOpType::Declare => 0,
+            BinOpType::Assign => 1,
+            BinOpType::LOr => 2,
+            BinOpType::LAnd => 3,
+            BinOpType::BOr => 4,
+            BinOpType::BXor => 5,
+            BinOpType::BAnd => 6,
+            BinOpType::EquEqu | BinOpType::NotEqu => 7,
+            BinOpType::Less | BinOpType::LessEqu | BinOpType::Greater | BinOpType::GreaterEqu => 8,
+            BinOpType::Shl | BinOpType::Shr => 9,
+            BinOpType::Add | BinOpType::Sub => 10,
+            BinOpType::Mul | BinOpType::Div | BinOpType::Mod => 11,
+        }
+    }
+}

src/bytecode.rs

@@ -1,197 +0,0 @@
-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

@@ -1,7 +1,7 @@
-use std::{collections::HashMap, fmt::Display, rc::Rc};
+use std::{fmt::Display, rc::Rc};
 
 use crate::{
-    ast::{Ast, BinOpType, Expr, Stmt, UnOpType},
+    ast::{Ast, BinOpType, Expression, If, Statement, UnOpType},
     lexer::lex,
     parser::parse,
 };
@@ -9,126 +9,143 @@ use crate::{
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum Value {
     I64(i64),
-    Str(Rc<String>),
+    String(Rc<String>),
 }
 
 pub struct Interpreter {
-    /// The variable table maps all variables by their names to their values
-    vartable: HashMap<String, Value>,
+    // Variable table stores the runtime values of variables
+    vartable: Vec<(String, Value)>,
 }
 
 impl Interpreter {
     pub fn new() -> Self {
-        let vartable = HashMap::new();
-        Self { vartable }
+        Self {
+            vartable: Vec::new(),
+        }
     }
 
-    pub fn run_text(&mut self, code: &str, print_tokens: bool, print_ast: bool) {
-        let tokens = lex(code);
+    fn get_var(&self, name: &str) -> Option<Value> {
+        self.vartable
+            .iter()
+            .rev()
+            .find(|it| it.0 == name)
+            .map(|it| it.1.clone())
+    }
+
+    fn get_var_mut(&mut self, name: &str) -> Option<&mut Value> {
+        self.vartable
+            .iter_mut()
+            .rev()
+            .find(|it| it.0 == name)
+            .map(|it| &mut it.1)
+    }
+
+    pub fn run_str(&mut self, code: &str, print_tokens: bool, print_ast: bool) {
+        let tokens = lex(code).unwrap();
         if print_tokens {
             println!("Tokens: {:?}", tokens);
         }
+
         let ast = parse(tokens);
         if print_ast {
-            println!("Ast:\n{:#?}", ast);
+            println!("{:#?}", ast);
         }
+
         self.run(&ast);
     }
 
     pub fn run(&mut self, prog: &Ast) {
+        let vartable_len = self.vartable.len();
         for stmt in &prog.prog {
             match stmt {
-                Stmt::Expr(expr) => {
+                Statement::Expr(expr) => {
                     self.resolve_expr(expr);
                 }
-                Stmt::DbgPrint(expr) => {
-                    let result = self.resolve_expr(expr);
-                    println!("{:?}", result);
+
+                Statement::Loop(looop) => {
+                    // loop runs as long condition != 0
+                    loop {
+                        if matches!(self.resolve_expr(&looop.condition), Value::I64(0)) {
+                            break;
+                        }
+
+                        self.run(&looop.body);
+
+                        if let Some(adv) = &looop.advancement {
+                            self.resolve_expr(&adv);
+                        }
+                    }
                 }
-                Stmt::Print(expr) => {
+
+                Statement::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) => {
+                Statement::If(If {
+                    condition,
+                    body_true,
+                    body_false,
+                }) => {
                     if matches!(self.resolve_expr(condition), Value::I64(0)) {
-                        self.run(body_else);
+                        self.run(body_false);
                     } else {
-                        self.run(body_if);
+                        self.run(body_true);
                     }
                 }
             }
         }
+
+        self.vartable.truncate(vartable_len);
     }
 
-    fn resolve_expr(&mut self, expr: &Expr) -> Value {
+    fn resolve_expr(&mut self, expr: &Expression) -> 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(),
-            },
+            Expression::I64(val) => Value::I64(*val),
+            Expression::String(text) => Value::String(text.clone()),
+            Expression::BinOp(bo, lhs, rhs) => self.resolve_binop(bo, lhs, rhs),
+            Expression::UnOp(uo, operand) => self.resolve_unop(uo, operand),
+            Expression::Var(name) => self.resolve_var(name),
         }
     }
 
-    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"),
+    fn resolve_var(&mut self, name: &str) -> Value {
+        match self.get_var(name) {
+            Some(val) => val.clone(),
+            None => panic!("Variable '{}' used but not declared", name),
+        }
+    }
+
+    fn resolve_unop(&mut self, uo: &UnOpType, operand: &Expression) -> Value {
+        let operand = self.resolve_expr(operand);
+
+        match (operand, uo) {
+            (Value::I64(val), UnOpType::Negate) => Value::I64(-val),
+            (Value::I64(val), UnOpType::BNot) => Value::I64(!val),
+            (Value::I64(val), UnOpType::LNot) => Value::I64(if val == 0 { 1 } else { 0 }),
+            _ => panic!("Value type is not compatible with unary operation"),
+        }
+    }
+
+    fn resolve_binop(&mut self, bo: &BinOpType, lhs: &Expression, rhs: &Expression) -> Value {
+        let rhs = self.resolve_expr(rhs);
+
+        match (&bo, &lhs) {
+            (BinOpType::Declare, Expression::Var(name)) => {
+                self.vartable.push((name.clone(), rhs.clone()));
+                return rhs;
             }
+            (BinOpType::Assign, Expression::Var(name)) => {
+                match self.get_var_mut(name) {
+                    Some(val) => *val = rhs.clone(),
+                    None => panic!("Runtime Error: Trying to assign value to undeclared variable"),
+                }
+                return rhs;
+            }
+            _ => (),
         }
 
         let lhs = self.resolve_expr(lhs);
-        let rhs = self.resolve_expr(rhs);
 
         match (lhs, rhs) {
             (Value::I64(lhs), Value::I64(rhs)) => match bo {
@@ -140,36 +157,29 @@ impl Interpreter {
                 BinOpType::BOr => Value::I64(lhs | rhs),
                 BinOpType::BAnd => Value::I64(lhs & rhs),
                 BinOpType::BXor => Value::I64(lhs ^ rhs),
+                BinOpType::LAnd => Value::I64(if (lhs != 0) && (rhs != 0) { 1 } else { 0 }),
+                BinOpType::LOr => Value::I64(if (lhs != 0) || (rhs != 0) { 1 } else { 0 }),
                 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!(),
+                BinOpType::EquEqu => Value::I64(if lhs == rhs { 1 } else { 0 }),
+                BinOpType::NotEqu => Value::I64(if lhs != rhs { 1 } else { 0 }),
+                BinOpType::Less => Value::I64(if lhs < rhs { 1 } else { 0 }),
+                BinOpType::LessEqu => Value::I64(if lhs <= rhs { 1 } else { 0 }),
+                BinOpType::Greater => Value::I64(if lhs > rhs { 1 } else { 0 }),
+                BinOpType::GreaterEqu => Value::I64(if lhs >= rhs { 1 } else { 0 }),
+
+                BinOpType::Declare | BinOpType::Assign => unreachable!(),
             },
             _ => 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),
+            Value::String(text) => write!(f, "{}", text),
         }
     }
 }
@@ -177,21 +187,26 @@ impl Display for Value {
 #[cfg(test)]
 mod test {
     use super::{Interpreter, Value};
-    use crate::ast::{BinOpType, Expr};
+    use crate::ast::{BinOpType, Expression};
 
     #[test]
     fn test_interpreter_expr() {
         // Expression: 1 + 2 * 3 + 4
         // With precedence: (1 + (2 * 3)) + 4
-        let ast = Expr::BinOp(
+        let ast = Expression::BinOp(
             BinOpType::Add,
-            Expr::BinOp(
+            Expression::BinOp(
                 BinOpType::Add,
-                Expr::I64(1).into(),
-                Expr::BinOp(BinOpType::Mul, Expr::I64(2).into(), Expr::I64(3).into()).into(),
+                Expression::I64(1).into(),
+                Expression::BinOp(
+                    BinOpType::Mul,
+                    Expression::I64(2).into(),
+                    Expression::I64(3).into(),
+                )
+                .into(),
             )
             .into(),
-            Expr::I64(4).into(),
+            Expression::I64(4).into(),
         );
 
         let expected = Value::I64(11);

src/lexer.rs

@@ -1,14 +1,31 @@
+use crate::token::Token;
+use anyhow::Result;
 use std::{iter::Peekable, str::Chars};
+use thiserror::Error;
 
-use crate::token::{Keyword, Literal, Token};
+#[derive(Debug, Error)]
+pub enum LexErr {
+    #[error("Failed to parse '{0}' as i64")]
+    NumericParse(String),
+
+    #[error("Invalid escape character '\\{0}'")]
+    InvalidStrEscape(char),
+
+    #[error("Lexer encountered unexpected char: '{0}'")]
+    UnexpectedChar(char),
+
+    #[error("Missing closing string quote '\"'")]
+    MissingClosingString,
+}
 
 /// Lex the provided code into a Token Buffer
-pub fn lex(code: &str) -> Vec<Token> {
+pub fn lex(code: &str) -> Result<Vec<Token>, LexErr> {
     let mut lexer = Lexer::new(code);
     lexer.lex()
 }
 
 struct Lexer<'a> {
+    /// The sourcecode text as an iterator over the chars
     code: Peekable<Chars<'a>>,
 }
 
@@ -18,29 +35,21 @@ 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> {
+    fn lex(&mut self) -> Result<Vec<Token>, LexErr> {
         let mut tokens = Vec::new();
 
         loop {
             match self.next() {
-                // End of text
+                // Stop lexing at EOF
                 '\0' => break,
 
                 // Skip whitespace
-                ' ' | '\r' | '\n' | '\t' => (),
+                ' ' | '\t' | '\n' | '\r' => (),
 
-                // Handle tokens that span two characters
+                // Line comment. Consume every char until linefeed (next line)
+                '/' if matches!(self.peek(), '/') => while !matches!(self.next(), '\n' | '\0') {},
+
+                // Double character tokens
                 '>' if matches!(self.peek(), '>') => {
                     self.next();
                     tokens.push(Token::Shr);
@@ -51,26 +60,35 @@ impl<'a> Lexer<'a> {
                 }
                 '=' if matches!(self.peek(), '=') => {
                     self.next();
-                    tokens.push(Token::Equ);
+                    tokens.push(Token::EquEqu);
                 }
                 '!' if matches!(self.peek(), '=') => {
                     self.next();
-                    tokens.push(Token::Neq);
+                    tokens.push(Token::NotEqu);
                 }
                 '<' if matches!(self.peek(), '=') => {
                     self.next();
-                    tokens.push(Token::Le);
+                    tokens.push(Token::LAngleEqu);
                 }
                 '>' if matches!(self.peek(), '=') => {
                     self.next();
-                    tokens.push(Token::Ge);
+                    tokens.push(Token::RAngleEqu);
                 }
-                '$' if matches!(self.peek(), '$') => {
+                '<' if matches!(self.peek(), '-') => {
                     self.next();
-                    tokens.push(Token::DoubleDollar);
+                    tokens.push(Token::LArrow);
+                }
+                '&' if matches!(self.peek(), '&') => {
+                    self.next();
+                    tokens.push(Token::LAnd);
+                }
+                '|' if matches!(self.peek(), '|') => {
+                    self.next();
+                    tokens.push(Token::LOr);
                 }
 
-                // Handle tokens that span one character
+                // Single character tokens
+                ';' => tokens.push(Token::Semicolon),
                 '+' => tokens.push(Token::Add),
                 '-' => tokens.push(Token::Sub),
                 '*' => tokens.push(Token::Mul),
@@ -81,34 +99,36 @@ impl<'a> Lexer<'a> {
                 '^' => 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),
+                '~' => tokens.push(Token::Tilde),
+                '<' => tokens.push(Token::LAngle),
+                '>' => tokens.push(Token::RAngle),
+                '=' => tokens.push(Token::Equ),
+                '{' => tokens.push(Token::LBraces),
+                '}' => tokens.push(Token::RBraces),
+                '!' => tokens.push(Token::LNot),
 
-                // Handle special multicharacter tokens
+                // Special tokens with variable length
 
-                // Lex numbers
-                ch @ '0'..='9' => tokens.push(self.lex_number(ch)),
+                // Lex multiple characters together as numbers
+                ch @ '0'..='9' => tokens.push(self.lex_number(ch)?),
 
-                // Lex strings
-                '"' => tokens.push(self.lex_string()),
+                // Lex multiple characters together as a string
+                '"' => tokens.push(self.lex_str()?),
 
-                // Lex identifiers
-                ch @ ('a'..='z' | 'A'..='Z' | '_') => tokens.push(self.lex_ident(ch)),
+                // Lex multiple characters together as identifier
+                ch @ ('a'..='z' | 'A'..='Z' | '_') => tokens.push(self.lex_identifier(ch)?),
 
-                // Any other character is unexpected
-                ch => panic!("Lexer encountered unexpected char: '{}'", ch),
+                ch => Err(LexErr::UnexpectedChar(ch))?,
             }
         }
 
-        tokens
+        Ok(tokens)
     }
 
-    fn lex_number(&mut self, first_char: char) -> Token {
+    /// Lex multiple characters as a number until encountering a non numeric digit. This includes
+    /// the first character
+    fn lex_number(&mut self, first_char: char) -> Result<Token, LexErr> {
+        // String representation of the integer value
         let mut sval = String::from(first_char);
 
         // Do as long as a next char exists and it is a numeric char
@@ -127,101 +147,105 @@ impl<'a> Lexer<'a> {
             }
         }
 
-        // TODO: We only added numeric chars to the string, but the conversion could still fail
-        Token::Literal(Literal::I64(sval.parse().unwrap()))
+        // Try to convert the string representation of the value to i64
+        let i64val = sval.parse().map_err(|_| LexErr::NumericParse(sval))?;
+        Ok(Token::I64(i64val))
     }
 
-    /// Lex an identifier from the character stream. The first char has to have been consumed
-    /// from the stream already and is passed as an argument instead.
-    fn lex_ident(&mut self, first_char: char) -> Token {
-        let mut ident = String::from(first_char);
+    /// Lex characters as a string until encountering an unescaped closing doublequoute char '"'
+    fn lex_str(&mut self) -> Result<Token, LexErr> {
+        // Opening " was consumed in match
 
-        // 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 a string token from the character stream. This requires the initial quote '"' to be
-    /// consumed before.
-    fn lex_string(&mut self) -> Token {
         let mut text = String::new();
 
-        let mut escape = false;
-
-        // Do as long as a next char exists and it is not '"'
+        // Read all chars until encountering the closing "
         loop {
-            if escape {
-                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()),
-                }
+            match self.peek() {
+                '"' => break,
+                // If the end of file is reached while still waiting for '"', error out
+                '\0' => Err(LexErr::MissingClosingString)?,
+                _ => match self.next() {
+                    // Backshlash indicates an escaped character
+                    '\\' => match self.next() {
+                        'n' => text.push('\n'),
+                        'r' => text.push('\r'),
+                        't' => text.push('\t'),
+                        '\\' => text.push('\\'),
+                        '"' => text.push('"'),
+                        ch => Err(LexErr::InvalidStrEscape(ch))?,
+                    },
+                    // All other characters are simply appended to the string
+                    ch => text.push(ch),
+                },
             }
         }
 
-        Token::Literal(Literal::Str(text))
+        // Consume closing "
+        self.next();
+
+        Ok(Token::String(text))
+    }
+
+    /// Lex characters from the text as an identifier. This includes the first character passed in
+    fn lex_identifier(&mut self, first_char: char) -> Result<Token, LexErr> {
+        let mut ident = String::from(first_char);
+
+        // Do as long as a next char exists and it is a valid char for an identifier
+        loop {
+            match self.peek() {
+                // In the middle of an identifier numbers are also allowed
+                'a'..='z' | 'A'..='Z' | '0'..='9' | '_' => {
+                    ident.push(self.next());
+                }
+                // Next char is not valid, so stop and finish the ident token
+                _ => break,
+            }
+        }
+
+        // Check for pre-defined keywords
+        let token = match ident.as_str() {
+            "loop" => Token::Loop,
+            "print" => Token::Print,
+            "if" => Token::If,
+            "else" => Token::Else,
+
+            // If it doesn't match a keyword, it is a normal identifier
+            _ => Token::Ident(ident),
+        };
+
+        Ok(token)
+    }
+
+    /// Advance to next character and return the removed char
+    fn next(&mut self) -> char {
+        self.code.next().unwrap_or('\0')
+    }
+
+    /// Get the next character without removing it
+    fn peek(&mut self) -> char {
+        self.code.peek().copied().unwrap_or('\0')
     }
 }
 
 #[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 expected = vec![
-            Token::Literal(Literal::I64(33)),
+            Token::I64(33),
             Token::Add,
-            Token::Literal(Literal::I64(5)),
+            Token::I64(5),
             Token::Mul,
-            Token::Literal(Literal::I64(2)),
+            Token::I64(2),
             Token::Add,
-            Token::Literal(Literal::I64(4456467)),
+            Token::I64(4456467),
             Token::Mul,
-            Token::Literal(Literal::I64(2334)),
+            Token::I64(2334),
             Token::Add,
-            Token::Literal(Literal::I64(3)),
+            Token::I64(3),
             Token::Mod,
             Token::Sub,
             Token::Div,
@@ -232,7 +256,7 @@ mod tests {
             Token::Shr,
         ];
 
-        let actual = lex(code);
+        let actual = lex(code).unwrap();
         assert_eq!(expected, actual);
     }
 }

src/lib.rs

@@ -1,7 +1,5 @@
 pub mod lexer;
-pub mod parser;
-pub mod interpreter;
 pub mod token;
+pub mod parser;
 pub mod ast;
-pub mod bytecode;
-pub mod vm;
+pub mod interpreter;

src/main.rs

@@ -1,6 +1,10 @@
-use std::{env::args, io::Write};
+use std::{
+    env::args,
+    fs,
+    io::{stdin, stdout, Write},
+};
 
-use nek_lang::{interpreter::Interpreter, lexer::lex, parser::parse, bytecode::compile, vm::Vm};
+use nek_lang::interpreter::Interpreter;
 
 #[derive(Debug, Default)]
 struct CliConfig {
@@ -11,53 +15,41 @@ struct CliConfig {
 }
 
 fn main() {
-    let mut cfg = CliConfig::default();
+    let mut conf = CliConfig::default();
 
+    // Go through all commandline arguments except the first (filename)
     for arg in args().skip(1) {
         match arg.as_str() {
-            "--tokens" | "-t" => cfg.print_tokens = true,
-            "--ast" | "-a" => cfg.print_ast = true,
-            "--interactive" | "-i" => cfg.interactive = true,
-            file if cfg.file.is_none() => cfg.file = Some(file.to_string()),
+            "--token" | "-t" => conf.print_tokens = true,
+            "--ast" | "-a" => conf.print_ast = true,
+            "--interactive" | "-i" => conf.interactive = true,
+            file if conf.file.is_none() => conf.file = Some(file.to_string()),
             _ => panic!("Invalid argument: '{}'", arg),
         }
     }
 
     let mut interpreter = Interpreter::new();
 
-    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 let Some(file) = &conf.file {
+        let code = fs::read_to_string(file).expect(&format!("File not found: '{}'", file));
+        interpreter.run_str(&code, conf.print_tokens, conf.print_ast);
     }
 
-    if cfg.interactive || cfg.file.is_none() {
-
+    if conf.interactive || conf.file.is_none() {
         let mut code = String::new();
 
         loop {
             print!(">> ");
-            std::io::stdout().flush().unwrap();
+            stdout().flush().unwrap();
 
             code.clear();
-            std::io::stdin().read_line(&mut code).unwrap();
-            let code = code.trim();
+            stdin().read_line(&mut code).unwrap();
 
-            if code == "exit" {
+            if code.trim() == "exit" {
                 break;
             }
 
-            interpreter.run_text(&code, cfg.print_tokens, cfg.print_ast);
+            interpreter.run_str(&code, conf.print_tokens, conf.print_ast);
         }
     }
 }

src/parser.rs

@@ -1,9 +1,13 @@
 use std::iter::Peekable;
 
-use crate::{
-    ast::{Ast, BinOpType, Expr, Stmt, UnOpType},
-    token::{Keyword, Literal, Token},
-};
+use crate::ast::*;
+use crate::token::Token;
+
+/// Parse the given tokens into an abstract syntax tree
+pub fn parse<T: Iterator<Item = Token>, A: IntoIterator<IntoIter = T>>(tokens: A) -> Ast {
+    let mut parser = Parser::new(tokens);
+    parser.parse()
+}
 
 struct Parser<T: Iterator<Item = Token>> {
     tokens: Peekable<T>,
@@ -16,171 +20,149 @@ impl<T: Iterator<Item = Token>> Parser<T> {
         Self { tokens }
     }
 
-    /// 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)
-    }
-
+    /// Parse tokens into an abstract syntax tree. This will continuously parse statements until
+    /// encountering end-of-file or a block end '}' .
     fn parse(&mut self) -> Ast {
         let mut prog = Vec::new();
 
         loop {
-            let stmt = match self.peek() {
+            match self.peek() {
                 Token::Semicolon => {
                     self.next();
-                    continue;
                 }
-                Token::EoF => break,
-                Token::RBrace => break,
+                Token::EoF | Token::RBraces => 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);
+                // By default try to lex a statement
+                _ => prog.push(self.parse_stmt()),
+            }
         }
 
         Ast { prog }
     }
 
-    fn parse_for(&mut self) -> Stmt {
-        if !matches!(self.next(), Token::Keyword(Keyword::For)) {
-            panic!("Error parsing for: Expected for token");
+    /// Parse a single statement from the tokens.
+    fn parse_stmt(&mut self) -> Statement {
+        match self.peek() {
+            Token::Loop => Statement::Loop(self.parse_loop()),
+
+            Token::Print => {
+                self.next();
+
+                let expr = self.parse_expr();
+
+                // After a statement, there must be a semicolon
+                if !matches!(self.next(), Token::Semicolon) {
+                    panic!("Expected semicolon after statement");
+                }
+
+                Statement::Print(expr)
+            }
+
+            Token::If => Statement::If(self.parse_if()),
+
+            // If it is not a loop, try to lex as an expression
+            _ => {
+                let stmt = Statement::Expr(self.parse_expr());
+
+                // After a statement, there must be a semicolon
+                if !matches!(self.next(), Token::Semicolon) {
+                    panic!("Expected semicolon after statement");
+                }
+
+                stmt
+            }
         }
-
-        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");
+    /// Parse an if statement from the tokens
+    fn parse_if(&mut self) -> If {
+        if !matches!(self.next(), Token::If) {
+            panic!("Error lexing if: Expected if token");
         }
 
         let condition = self.parse_expr();
 
-        if !matches!(self.next(), Token::LBrace) {
-            panic!("Error parsing if: Expected '{{' token");
+        if !matches!(self.next(), Token::LBraces) {
+            panic!("Error lexing if: Expected '{{'")
         }
 
-        let body_if = self.parse();
+        let body_true = self.parse();
 
-        if !matches!(self.next(), Token::RBrace) {
-            panic!("Error parsing if: Expected '}}' token");
+        if !matches!(self.next(), Token::RBraces) {
+            panic!("Error lexing if: Expected '}}'")
         }
 
-        let mut body_else = Ast { prog: Vec::new() };
+        let mut body_false = Ast::default();
 
-        if matches!(self.peek(), Token::Keyword(Keyword::Else)) {
+        if matches!(self.peek(), Token::Else) {
             self.next();
 
-            if !matches!(self.next(), Token::LBrace) {
-                panic!("Error parsing else: Expected '{{' token");
+            if !matches!(self.next(), Token::LBraces) {
+                panic!("Error lexing if: Expected '{{'")
             }
 
-            body_else = self.parse();
+            body_false = self.parse();
 
-            if !matches!(self.next(), Token::RBrace) {
-                panic!("Error parsing else: Expected '}}' token");
+            if !matches!(self.next(), Token::RBraces) {
+                panic!("Error lexing if: Expected '}}'")
             }
         }
 
-        Stmt::If(condition, body_if, body_else)
+        If {
+            condition,
+            body_true,
+            body_false,
+        }
     }
 
-    fn parse_while(&mut self) -> Stmt {
-        if !matches!(self.next(), Token::Keyword(Keyword::While)) {
-            panic!("Error parsing while: Expected while token");
+    /// Parse a loop statement from the tokens
+    fn parse_loop(&mut self) -> Loop {
+        if !matches!(self.next(), Token::Loop) {
+            panic!("Error lexing loop: Expected loop token");
         }
 
         let condition = self.parse_expr();
+        let mut advancement = None;
 
-        if !matches!(self.next(), Token::LBrace) {
-            panic!("Error parsing while: Expected '{{' token");
+        let body;
+
+        match self.next() {
+            Token::LBraces => {
+                body = self.parse();
+            }
+
+            Token::Semicolon => {
+                advancement = Some(self.parse_expr());
+
+                if !matches!(self.next(), Token::LBraces) {
+                    panic!("Error lexing loop: Expected '{{'")
+                }
+
+                body = self.parse();
+            }
+
+            _ => panic!("Error lexing loop: Expected ';' or '{{'"),
         }
 
-        let body = self.parse();
-
-        if !matches!(self.next(), Token::RBrace) {
-            panic!("Error parsing while: Expected '}}' token");
+        if !matches!(self.next(), Token::RBraces) {
+            panic!("Error lexing loop: Expected '}}'")
         }
 
-        Stmt::While(condition, body)
+        Loop {
+            condition,
+            advancement,
+            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 {
+    /// Parse a single expression from the tokens
+    fn parse_expr(&mut self) -> Expression {
         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: Expr, min_prec: u8) -> Expr {
+    fn parse_expr_precedence(&mut self, mut lhs: Expression, min_prec: u8) -> Expression {
         while let Some(binop) = &self.peek().try_to_binop() {
             // Stop if the next operator has a lower binding power
             if !(binop.precedence() >= min_prec) {
@@ -201,75 +183,74 @@ impl<T: Iterator<Item = Token>> Parser<T> {
                 rhs = self.parse_expr_precedence(rhs, binop.precedence() + 1);
             }
 
-            lhs = Expr::BinOp(binop, lhs.into(), rhs.into());
+            lhs = Expression::BinOp(binop, lhs.into(), rhs.into());
         }
 
         lhs
     }
 
     /// Parse a primary expression (for now only number)
-    fn parse_primary(&mut self) -> Expr {
+    fn parse_primary(&mut self) -> Expression {
         match self.next() {
-            Token::Literal(Literal::I64(val)) => Expr::I64(val),
+            // Literal i64
+            Token::I64(val) => Expression::I64(val),
 
-            Token::Literal(Literal::Str(text)) => Expr::Str(text.into()),
+            // Literal String
+            Token::String(text) => Expression::String(text.into()),
 
-            Token::Ident(name) => Expr::Ident(name),
+            Token::Ident(name) => Expression::Var(name),
 
+            // Parentheses grouping
             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();
+                let inner_expr = self.parse_expr();
 
-                // If there is no closing parenthesis after the expression, it is a syntax error
+                // Verify that there is a closing parenthesis
                 if !matches!(self.next(), Token::RParen) {
-                    panic!("Error parsing primary expr: Missing closing parenthesis ')'");
+                    panic!("Error parsing primary expr: Exepected closing parenthesis ')'");
                 }
 
-                inner
+                inner_expr
             }
 
-            Token::Sub => Expr::UnOp(UnOpType::Neg, self.parse_primary().into()),
+            // Unary negation
+            Token::Sub => {
+                let operand = self.parse_primary();
+                Expression::UnOp(UnOpType::Negate, operand.into())
+            }
+
+            // Unary bitwise not (bitflip)
+            Token::Tilde => {
+                let operand = self.parse_primary();
+                Expression::UnOp(UnOpType::BNot, operand.into())
+            }
+
+            // Unary logical not
+            Token::LNot => {
+                let operand = self.parse_primary();
+                Expression::UnOp(UnOpType::LNot, operand.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)
+    }
 
-pub fn parse<T: Iterator<Item = Token>, A: IntoIterator<IntoIter = T>>(tokens: A) -> Ast {
-    let mut parser = Parser::new(tokens);
-    parser.parse()
-}
-
-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::Assign => 0,
-            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,
-        }
+    /// Advance to next Token and return the removed Token
+    fn next(&mut self) -> Token {
+        self.tokens.next().unwrap_or(Token::EoF)
     }
 }
 
 #[cfg(test)]
 mod tests {
-    use super::{parse, BinOpType, Expr};
+    use super::{parse, BinOpType, Expression};
     use crate::{
-        parser::{Ast, Stmt},
-        token::{Literal, Token},
+        parser::{Ast, Statement},
+        token::Token,
     };
 
     #[test]
@@ -277,28 +258,34 @@ mod tests {
         // Expression: 1 + 2 * 3 + 4
         // With precedence: (1 + (2 * 3)) + 4
         let tokens = [
-            Token::Literal(Literal::I64(1)),
+            Token::I64(1),
             Token::Add,
-            Token::Literal(Literal::I64(2)),
+            Token::I64(2),
             Token::Mul,
-            Token::Literal(Literal::I64(3)),
+            Token::I64(3),
             Token::Sub,
-            Token::Literal(Literal::I64(4)),
+            Token::I64(4),
+            Token::Semicolon,
         ];
 
-        let expected = Expr::BinOp(
+        let expected = Statement::Expr(Expression::BinOp(
             BinOpType::Sub,
-            Expr::BinOp(
+            Expression::BinOp(
                 BinOpType::Add,
-                Expr::I64(1).into(),
-                Expr::BinOp(BinOpType::Mul, Expr::I64(2).into(), Expr::I64(3).into()).into(),
+                Expression::I64(1).into(),
+                Expression::BinOp(
+                    BinOpType::Mul,
+                    Expression::I64(2).into(),
+                    Expression::I64(3).into(),
+                )
+                .into(),
             )
             .into(),
-            Expr::I64(4).into(),
-        );
+            Expression::I64(4).into(),
+        ));
 
         let expected = Ast {
-            prog: vec![Stmt::Expr(expected)],
+            prog: vec![expected],
         };
 
         let actual = parse(tokens);

src/token.rs

@@ -1,63 +1,39 @@
 use crate::ast::BinOpType;
 
 #[derive(Debug, PartialEq, Eq)]
-pub enum Literal {
+pub enum Token {
     /// Integer literal (64-bit)
     I64(i64),
 
-    /// String literal ("Some string")
-    Str(String),
-}
+    /// String literal
+    String(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)
+    /// Identifier (name for variables, functions, ...)
     Ident(String),
 
-    /// Specific identifiers that have a special meaning as keywords
-    Keyword(Keyword),
+    /// Loop keyword (loop)
+    Loop,
 
-    /// Left parenthesis ('(')
+    /// Print keyword (print)
+    Print,
+
+    /// If keyword (if)
+    If,
+
+    /// Else keyword (else)
+    Else,
+
+    /// Left Parenthesis ('(')
     LParen,
 
-    /// Right parentheses (')')
+    /// Right Parenthesis (')')
     RParen,
 
-    /// Left brace ({)
-    LBrace,
+    /// Left curly braces ({)
+    LBraces,
 
-    /// Right brace (})
-    RBrace,
-
-    /// Dollar sign ($)
-    Dollar,
-
-    /// Double Dollar sign ($$)
-    DoubleDollar,
-
-    /// Assignment (single equal) (=)
-    Assign,
+    /// Right curly braces (})
+    RBraces,
 
     /// Plus (+)
     Add,
@@ -74,6 +50,12 @@ pub enum Token {
     /// Percent (%)
     Mod,
 
+    /// Equal Equal (==)
+    EquEqu,
+
+    /// Exclamationmark Equal (!=)
+    NotEqu,
+
     /// Pipe (|)
     BOr,
 
@@ -83,30 +65,42 @@ pub enum Token {
     /// Circumflex (^)
     BXor,
 
+    /// Logical AND (&&)
+    LAnd,
+
+    /// Logical OR (||)
+    LOr,
+
     /// Shift Left (<<)
     Shl,
 
     /// Shift Right (>>)
     Shr,
 
-    /// Equal sign (==)
+    /// Tilde (~)
+    Tilde,
+
+    /// Logical not (!)
+    LNot,
+
+    /// Left angle bracket (<)
+    LAngle,
+
+    /// Right angle bracket (>)
+    RAngle,
+
+    /// Left angle bracket Equal (<=)
+    LAngleEqu,
+
+    /// Left angle bracket Equal (>=)
+    RAngleEqu,
+
+    /// Left arrow (<-)
+    LArrow,
+
+    /// Equal Sign (=)
     Equ,
 
-    /// Not Equal sign (!=)
-    Neq,
-
-    /// Greater than (>)
-    Gt,
-
-    /// Greater or equal (>=)
-    Ge,
-
-    /// Less than (<)
-    Lt,
-
-    /// Less or equal (<=)
-    Le,
-
     /// Semicolon (;)
     Semicolon,
 
@@ -128,18 +122,23 @@ impl Token {
             Token::BOr => BinOpType::BOr,
             Token::BXor => BinOpType::BXor,
 
+            Token::LAnd => BinOpType::LAnd,
+            Token::LOr => BinOpType::LOr,
+
             Token::Shl => BinOpType::Shl,
             Token::Shr => BinOpType::Shr,
 
-            Token::Equ => BinOpType::Equ,
-            Token::Neq => BinOpType::Neq,
+            Token::EquEqu => BinOpType::EquEqu,
+            Token::NotEqu => BinOpType::NotEqu,
 
-            Token::Gt => BinOpType::Gt,
-            Token::Ge => BinOpType::Ge,
-            Token::Lt => BinOpType::Lt,
-            Token::Le => BinOpType::Le,
+            Token::LAngle => BinOpType::Less,
+            Token::LAngleEqu => BinOpType::LessEqu,
 
-            Token::Assign => BinOpType::Assign,
+            Token::RAngle => BinOpType::Greater,
+            Token::RAngleEqu => BinOpType::GreaterEqu,
+
+            Token::LArrow => BinOpType::Declare,
+            Token::Equ => BinOpType::Assign,
 
             _ => return None,
         })

src/vm.rs

@@ -1,208 +0,0 @@
-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
-    }
-}