Playing around with non enum based bytecode

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

Cargo.toml

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

README.md

@@ -1,400 +1,38 @@
 # NEK-Lang
-## Table of contents
-- [NEK-Lang](#nek-lang)
-  - [Table of contents](#table-of-contents)
-  - [Variables](#variables)
-    - [Declaration](#declaration)
-    - [Assignment](#assignment)
-  - [Datatypes](#datatypes)
-    - [I64](#i64)
-    - [String](#string)
-    - [Array](#array)
-  - [Expressions](#expressions)
-    - [General](#general)
-    - [Mathematical Operators](#mathematical-operators)
-    - [Bitwise Operators](#bitwise-operators)
-    - [Logical Operators](#logical-operators)
-    - [Equality & Relational Operators](#equality--relational-operators)
-  - [Control-Flow](#control-flow)
-    - [Loop](#loop)
-    - [If / Else](#if--else)
-    - [Block Scopes](#block-scopes)
-  - [Functions](#functions)
-    - [Function definition](#function-definition)
-    - [Function calls](#function-calls)
-  - [IO](#io)
-    - [Print](#print)
-  - [Comments](#comments)
-    - [Line comments](#line-comments)
-- [Feature Tracker](#feature-tracker)
-  - [High level Components](#high-level-components)
-  - [Language features](#language-features)
-- [Parsing Grammar](#parsing-grammar)
-  - [Expressions](#expressions-1)
-  - [Statements](#statements)
-- [Examples](#examples)
-- [Extras](#extras)
-  - [Visual Studio Code Language Support](#visual-studio-code-language-support)
-
-## Variables
-The variables are all contained in scopes. Variables defined in an outer scope can be accessed in 
-inner scoped. All variables defined in a scope that has ended do no longer exist and can't be 
-accessed.
-
-### Declaration
-- Declare and initialize a new variable
-- Declaring a previously declared variable again will shadow the previous variable
-- 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.
-
-## Datatypes
-The available variable datatypes are `i64` (64-bit signed integer), `string` (`"this is a string"`) and `array` (`[10]`)
-
-### I64
-- The normal default datatype is `i64` which is a 64-bit signed integer
-- Can be created by just writing an integer literal like `546`
-- Inside the number literal `_` can be inserted for visual separation `100_000`
-- The i64 values can be used as expected in calculations, conditions and so on
-```
-my_i64 <- 123_456;
-```
-
-### String
-- Strings mainly exist for formatting the text output of a program
-- Strings can be created by using doublequotes like in other languages `"Hello world"`
-- There is no way to access or change the characters of the string
-- Unicode characters are supported `"Hello 🌎"`
-- Escape characters `\n`, `\r`, `\t`, `\"`, `\\` are supported
-- String can be assigned to variables, just like i64
-```
-world <- "🌎";
-
-print "Hello ";
-print world;
-print "\n";
-```
-
-### Array
-- Arrays can contain any other datatypes and don't need to have the same type in all cells
-- Arrays can be created by using brackets with the size in between `[size]`
-- Arrays must be assigned to a variable in order to be used
-- All cells will be initialized with i64 0 values
-- The size can be any expression that results in a positive i64 value
-- The array size can't be changed after creation
-- The arrays data is always allocated on the heap
-- The array cells can be accessed by using the variable name and specifying the index in brackets 
-  `my_arr[index]`
-- The index can be any expression that results in a positive i64 value in the range of the arrays 
-  indices
-- The indices start with 0
-- When an array is passed to a function, it is passed by reference
-```
-width <- 5;
-heigt <- 5;
-
-// Initialize array of size 25, initialized with 25x 0
-my_array = [width * height];
-
-// Modify first value
-my_array[0] = 5;
-
-// Print first value
-// Outputs `5`
-print my_array[0];
-```
-
-## 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`.
-Note that logical operators like AND / OR do not support short-circuit evaluation. So Both sides of 
-the logical operation will be evaluated, even if it might not be necessary.
-- 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
-- The `loop` keyword can be used as an infinite loop, as a while loop or as a while loop with 
-  advancement (an expression that is executed after each loop)
-- If only `loop` is used, directly followed by the body, it is an infinite loop that needs to be 
-  terminated by using the `break` keyword
-- The `loop` keyword can be 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++
-- The `continue` keyword can be used to end the current loop iteration early
-- The `break` keyword can be used to fully break out of the current loop
-
-```
-// Print the numbers from 0 to 9
-
-// With endless loop
-i <- 0;
-loop {
-  if i >= 10 {
-    break;
-  }
-  print i;
-  i = i + 1;
-}
-
-// 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 blocks are wrapped in braces (`{ }`)
-- *Optional:* If there is an `else` after the *if-block*, there must be a following *if-false*, aka. else block
-- NOTE: Logical operators like AND / OR do not support short-circuit evaluation. So Both sides of 
-  the logical operations will be evaluated, even if it might not be necessary
-```
-a <- 1;
-b <- 2;
-if a == b {
-  // a is equal to b
-  print 1;
-} else {
-  // a is not equal to b
-  print 0;
-}
-```
-
-### Block Scopes
-
-- It is possible to create a limited scope for local variables that will no longer exist once the 
-  scope ends
-- Shadowing variables by redefining a variable in an inner scope is supported
-```
-var_in_outer_scope <- 5;
-{
-  var_in_inner_scope <- 3;
-  
-  // Inner scope can access both vars
-  print var_in_outer_scope;
-  print var_in_inner_scope;
-}
-
-// Outer scope is still valid
-print var_in_outer_scope;
-
-// !!! THIS DOES NOT WORK !!!
-// The inner scope has ended
-print var_in_inner_scope;
-```
-
-## Functions
-
-### Function definition
-- Functions can be defined by using the `fun` keyword, followed by the function name and the 
-  parameters in parentheses. After the parentheses, the body is specified inside a braces block
-- The function parameters are specified by only their names
-- The function body has its own scope
-- Parameters are only accessible inside the body
-- Variables from the outer scope can be accessed and modified if the are defined before the function
-- Variables from the outer scope are shadowed by parameters or local variables with the same name
-- The `return` keyword can be used to return a value from the function and exit it immediately
-- If no return is specified, a special `void` value is returned. That value can't be used in 
-  calculations or comparisons, but can be stored in a variable (even tho it doesn't make sense)
-- Functions can only be defined at the top-level. So defining a function inside of any other scoped 
-  block (like inside another function, if, loop, ...) is invalid
-- Functions can only be used after definition and there is no forward declaration right now
-- However a function can be called recursively inside of itself
-- Functions can't be redefined, so defining a function with an existing name is invalid
-```
-fun add_maybe(a, b) {
-  if a < 100 {
-    return a;
-  } else {
-    return a + b;
-  }
-}
-
-fun println(val) {
-  print val;
-  print "\n";
-}
-```
-
-### Function calls
-- Function calls are primary expressions, so they can be directly used in calculations (if they 
-  return appropriate values)
-- Function calls are performed by writing the function name, followed by the arguments in parentheses
-- The arguments can be any expressions, separated by commas
-```
-b <- 100;
-result <- add_maybe(250, b);
-
-// Prints 350 + new-line
-println(result);
-```
-
-## 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
-- To add a line break a string print can be used `print "\n";`
-```
-a <- 1;
-// Outputs `1` to the terminal
-print a;
-
-// Outputs a new-line to the terminal
-print "\n";
-```
-
-## 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
-- [x] Simple optimizer: Apply trivial optimizations to the Ast
+- [ ] Abstract Syntax Tree Optimizer
-  - [x] Precalculate binary ops / unary ops that have only literal operands
 
 ## Language features
 
-- [x] General expressions
+- [x] Math expressions
-  - [x] Arithmetic operations
+  - [x] Unary operators
-    - [x] Addition `a + b`
+    - [x] Negate `-X`
-    - [x] Subtraction `a - b`
+  - [x] Parentheses `(X+Y)*Z`
-    - [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] Local variables (for example inside loop, if, else, functions)
+- [x] While loop `while X { ... }`
-  - [x] Scoped block for specific local vars `{ ... }`
+- [x] If else statement `if X { ... } else { ... }`
-- [x] Statements with semicolon & Multiline programs
+  - [x] If Statement
-- [x] Control flow
+  - [x] Else statement
-  - [x] Loops
+- [ ] Line comments `//`
-    - [x] While-style loop `loop X { ... }`
-    - [x] For-style loop without with `X` as condition and `Y` as advancement `loop X; Y { ... }`
-    - [x] Infinite loop `loop { ... }`
-    - [x] Break `break`
-    - [x] Continue `continue`
-  - [x] If else statement `if X { ... } else { ... }`
-    - [x] If Statement
-    - [x] Else statement
-- [x] Line comments `//`
 - [x] Strings
-- [x] Arrays
+- [x] For loops `for X; Y; Z { ... }`
-  - [x] Creating array with size `X` as a variable `arr <- [X]`
+- [ ] IO Intrinsics
-  - [x] Accessing arrays by index `arr[X]`
-- [x] IO Intrinsics
   - [x] Print
-- [x] Functions
+  - [ ] ReadLine
-  - [x] Function declaration `fun f(X, Y, Z) { ... }`
-  - [x] Function calls `f(1, 2, 3)`
-  - [x] Function returns `return X`
-  - [x] Local variables
-  - [x] Pass arrays by-reference, i64 by-vale, string is a const ref
 
-# Parsing Grammar
+## Grammar
-
+### Expressions
-## Expressions
 ```
-ARRAY_LITERAL = "[" expr "]"
+LITERAL = I64 | Str
-ARRAY_ACCESS = IDENT "[" expr "]"
+expr_primary = LITERAL | IDENT | "(" expr ")" | "-" expr_primary
-FUN_CALL = IDENT "(" (expr ",")* expr? ")"
-LITERAL = I64_LITERAL | STR_LITERAL | ARRAY_LITERAL
-expr_primary = LITERAL | IDENT | FUN_CALL | ARRAY_ACCESS | "(" expr ")" | "-" expr_primary 
-             | "~" expr_primary
 expr_mul = expr_primary (("*" | "/" | "%") expr_primary)*
 expr_add = expr_mul (("+" | "-") expr_mul)*
 expr_shift = expr_add ((">>" | "<<") expr_add)*
@@ -403,38 +41,17 @@ 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_land = expr_bor ("&&" expr_bor)*
+expr = expr_bor
-expr_lor = expr_land ("||" expr_land)*
-expr = expr_lor
 ```
 
 ## Statements
 ```
-stmt_return = "return" expr ";"
+stmt_expr = expr
-stmt_break = "break" ";"
+stmt_let = "let" IDENT "=" expr
-stmt_continue = "continue" ";"
+stmt_while = "while" expr "{" (stmt)* "}"
-stmt_var_decl = IDENT "<-" expr ";"
+stmt_for = "for" stmt_let ";" expr ";" expr "{" (stmt)* "}"
-stmt_fun_decl = "fun" IDENT "(" (IDENT ",")* IDENT? ")" "{" stmt* "}"
+stmt_if = "if" expr "{" (stmt)* "}" ( "else" "{" (stmt)* "}" )
-stmt_expr = expr ";"
+stmt_dbgprint = "$$" expr
-stmt_block = "{" stmt* "}"
+stmt_print = "$" expr
-stmt_loop = "loop" (expr (";" expr)?)? "{" stmt* "}"
+stmt = stmt_expr | stmt_let | stmt_while | stmt_for | stmt_if | stmt_dbgprint | stmt_print
-stmt_if = "if" expr "{" stmt* "}" ("else" "{" stmt* "}")?
-stmt_print = "print" expr ";"
-stmt = stmt_return | stmt_break | stmt_continue | stmt_var_decl | stmt_fun_decl 
-     | stmt_expr | stmt_block | stmt_loop | stmt_if | stmt_print
 ```
-
-# Examples
-There are a bunch of examples in the [examples](examples/) directory. Those include (non-optimal) solutions to the first five project euler problems, as well as a [simple Game of Life implementation](examples/game_of_life.nek).
-
-To run an example via `cargo-run`, use:
-```
-cargo run --release -- examples/[NAME]
-```
-
-# Extras
-## Visual Studio Code Language Support
-A VSCode extension that provides simple syntax highlighing for nek is also available on 
-[gitlab](https://code.fbi.h-da.de/advanced-systems-programming-ws21/x4/nek-lang-vscode). Since this 
-is a very small scale project, the extension was not published and instuctions on how to install it 
-can be found in the mentioned repository.

examples/euler1.nek

@@ -1,15 +0,0 @@
-// 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

@@ -1,24 +0,0 @@
-// 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;
-loop a < 4_000_000 {
-    if a % 2 == 0 {
-        sum = sum + a;
-    }
-
-    tmp <- a;
-    a = b;
-    b = b + tmp;
-}
-
-print sum;
-

examples/euler3.nek

@@ -1,29 +0,0 @@
-// 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;
-        }
-        break;
-    }
-
-}
-
-print result;

examples/euler4.nek

@@ -1,31 +0,0 @@
-// 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
-
-fun reverse(n) {
-    rev <- 0;
-    loop n {
-        rev = rev * 10 + n % 10;
-        n = n / 10;
-    }
-    return rev;
-}
-
-res <- 0;
-
-i <- 100;
-loop i < 1_000; i = i + 1 {
-    k <- i;
-    loop k < 1_000; k = k + 1 {
-        num <- i * k;
-        num_rev <- reverse(num);
-
-        if num == num_rev && num > res {
-            res = num;
-        }
-    }
-}
-
-print res;

examples/euler4.py

@@ -1,24 +0,0 @@
-# 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
-
-def reverse(n):
-    rev = 0
-    while n:
-        rev = rev * 10 + n % 10
-        n //= 10
-    return rev
-
-res = 0
-
-for i in range(100, 1_000):
-    for k in range(i, 1_000):
-        num = i * k
-        num_rev = reverse(num)
-        
-        if num == num_rev and num > res:
-            res = num
-
-print(res)

examples/euler5.nek

@@ -1,23 +0,0 @@
-// 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
-
-fun gcd(x, y) {
-    loop y {
-        tmp <- x;
-        x = y;
-        y = tmp % y;
-    }
-
-    return x;
-}
-
-result <- 1;
-
-i <- 1;
-loop i <= 20; i = i + 1 {
-    result = result * (i / gcd(i, result));
-}
-
-print result;

examples/euler5.py

@@ -1,15 +0,0 @@
-# 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
-
-def gcd(x, y):
-    while y:
-        x, y = y, x % y
-    return x
-
-result = 1
-for i in range(1, 21):
-    result *= i // gcd(i, result)
-
-print(result)

examples/game_of_life.nek

@@ -1,134 +0,0 @@
-fun print_field(field, width, height) {
-    y <- 0;
-    loop y < height; y = y+1 {
-        x <- 0;
-        loop x < width; x = x+1 {
-            if field[y*height + x] {
-                print "# ";
-            } else {
-                print ". ";
-            }
-        }
-        print "\n";
-    }
-    print "\n";
-}
-
-fun count_neighbours(field, x, y, width, height) {
-    neighbours <- 0;
-    if y > 0 {
-        if x > 0 {
-            if field[(y-1)*width + (x-1)] {
-                // Top left
-                neighbours = neighbours + 1;
-            }
-        }
-
-        if field[(y-1)*width + x] {
-        // Top
-            neighbours = neighbours + 1;
-        }
-
-        if x < width-1 {
-            if field[(y-1)*width + (x+1)] {
-            // Top right
-                neighbours = neighbours + 1;
-            }
-        }
-    }
-
-    if x > 0 {
-        if field[y*width + (x-1)] {
-        // Left
-            neighbours = neighbours + 1;
-        }
-    }
-
-    if x < width-1 {
-        if field[y*width + (x+1)] {
-        // Right
-            neighbours = neighbours + 1;
-        }
-    }
-
-    
-    if y < height-1 {
-        if x > 0 {
-            if field[(y+1)*width + (x-1)] {
-            // Bottom left
-                neighbours = neighbours + 1;
-            }
-        }
-
-        if field[(y+1)*width + x] {
-        // Bottom
-            neighbours = neighbours + 1;
-        }
-
-        if x < width-1 {
-            if field[(y+1)*width + (x+1)] {
-            // Bottom right
-                neighbours = neighbours + 1;
-            }
-        }
-    }
-    return neighbours;
-}
-
-fun copy(from, to, len) {
-    i <- 0;
-    loop i < len; i = i + 1 {
-        to[i] = from[i];
-    }
-}
-
-// Set the width and height of the field
-width <- 10;
-height <- 10;
-
-// Create the main and temporary field
-field <- [width*height];
-field2 <- [width*height];
-
-// Preset the main field with a glider
-field[1] = 1;
-field[12] = 1;
-field[20] = 1;
-field[21] = 1;
-field[22] = 1;
-
-fun run_gol(num_rounds) {
-    runs <- 0;
-    loop runs < num_rounds; runs = runs + 1 {
-        // Print the field
-        print_field(field, width, height);
-
-        // Calculate next stage from field and store into field2
-        y <- 0;
-        loop y < height; y = y+1 {
-            x <- 0;
-            loop x < width; x = x+1 {
-
-                // Get the neighbours of the current cell
-                neighbours <- count_neighbours(field, x, y, width, height);
-
-                // Set the new cell according to the neighbour count
-                if neighbours < 2 || neighbours > 3 {
-                    field2[y*width + x] = 0;
-                } else {
-                    if neighbours == 3 {
-                        field2[y*width + x] = 1;
-                    } else {
-                        field2[y*width + x] = field[y*width + x];
-                    }
-                }
-                
-            }
-        }
-
-        // Transfer from field2 to field
-        copy(field2, field, width*height);
-    }
-}
-
-run_gol(32);

examples/recursive_fib.nek

@@ -1,9 +0,0 @@
-fun fib(n) {
-    if n <= 1 {
-        return n;
-    } else {
-        return fib(n-1) + fib(n-2);
-    }
-}
-
-print fib(30);

examples/recursive_fib.py

@@ -1,6 +0,0 @@
-def fib(n):
-    if n <= 1:
-        return n
-    return fib(n-1) + fib(n-2)
-
-print(fib(30))

examples/test_functions.nek

@@ -1,31 +0,0 @@
-fun square(a) {
-    return a * a;
-}
-
-fun add(a, b) {
-    return a + b;
-}
-
-fun mul(a, b) {
-    return a * b;
-}
-
-// Funtion with multiple args & nested calls to different functions
-fun addmul(a, b, c) {
-    return mul(add(a, b), c);
-}
-
-a <- 10;
-b <- 20;
-c <- 3;
-
-result <- addmul(a, b, c) + square(c);
-
-// Access and modify outer variable. Argument `a` must not be used from outer var
-fun sub_from_result(a) {
-    result = result - a;
-}
-
-sub_from_result(30);
-
-print result;

src/ast.rs

@@ -1,211 +1,104 @@
 use std::rc::Rc;
 
-use crate::stringstore::{Sid, StringStore};
+/// Types for binary operators
-
-/// Types for binary operations
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum BinOpType {
-    /// Addition ("+")
+    /// Addition
     Add,
 
-    /// Subtraction ("-")
+    /// Subtraction
     Sub,
 
-    /// Multiplication ("*")
+    /// Multiplication
     Mul,
 
-    /// Division ("/")
+    /// Divide
     Div,
 
-    /// Modulo / Remainder ("%")
+    /// Modulo
     Mod,
 
-    /// Compare Equal ("==")
+    /// Bitwise OR (inclusive or)
-    EquEqu,
-
-    /// Compare Not Equal ("!=")
-    NotEqu,
-
-    /// Compare Less than ("<")
-    Less,
-
-    /// Compare Less than or Equal ("<=")
-    LessEqu,
-
-    /// Compare Greater than (">")
-    Greater,
-
-    /// Compare Greater than or Equal (">=")
-    GreaterEqu,
-
-    /// Bitwise Or ("|")
     BOr,
 
-    /// Bitwise And ("&")
+    /// Bitwise And
     BAnd,
 
-    /// Bitwise Xor / Exclusive Or ("^")
+    /// Bitwise Xor (exclusive or)
     BXor,
 
-    /// Logical And ("&&")
+    /// Shift Left
-    LAnd,
-
-    /// Logical Or ("||")
-    LOr,
-
-    /// Bitwise Shift Left ("<<")
     Shl,
 
-    /// Bitwise Shift Right (">>")
+    /// Shift Right
     Shr,
 
-    /// Assign value to variable ("=")
+    /// 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 operations
+/// Types for unary operators
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum UnOpType {
-    /// Unary Negation ("-")
+    /// Negation
-    Negate,
+    Neg,
-
-    /// Bitwise Not / Bitflip ("~")
-    BNot,
-
-    /// Logical Not ("!")
-    LNot,
 }
 
-/// Ast Node for possible Expression variants
+/// A full program abstract syntax tree. This consists of zero or more statements that represents 
+/// a program.
 #[derive(Debug, PartialEq, Eq, Clone)]
-pub enum Expression {
+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
-    String(Sid),
+    Str(Rc<String>),
-
+    /// Identifier (variable name)
-    /// Array with size as an expression
+    Ident(String),
-    ArrayLiteral(Box<Expression>),
-    /// Array access with name, stackpos and position as expression
-    ArrayAccess(Sid, usize, Box<Expression>),
-
-    /// Function call with name, stackpos and the arguments as a vec of expressions
-    FunCall(Sid, usize, Vec<Expression>),
-
-    /// Variable with name and the stackpos from behind. This means that stackpos 0 refers to the 
-    /// last variable on the stack and not the first
-    Var(Sid, usize),
     /// Binary operation. Consists of type, left hand side and right hand side
-    BinOp(BinOpType, Box<Expression>, Box<Expression>),
+    BinOp(BinOpType, Box<Expr>, Box<Expr>),
-    /// Unary operation. Consists of type and operand
+    /// Unary operation. Consists of type and the value that is operated on
-    UnOp(UnOpType, Box<Expression>),
+    UnOp(UnOpType, Box<Expr>),
-}
-
-/// Ast Node for a loop
-#[derive(Debug, PartialEq, Eq, Clone)]
-pub struct Loop {
-    /// The condition that determines if the loop should continue
-    pub condition: Option<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: BlockScope,
-}
-
-/// Ast Node for an if
-#[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: BlockScope,
-    /// The if body that is executed when the condition is false
-    pub body_false: BlockScope,
-}
-
-/// Ast Node for a function declaration
-#[derive(Debug, PartialEq, Eq, Clone)]
-pub struct FunDecl {
-    /// The function name as StringID, stored in the stringstore
-    pub name: Sid,
-    /// The absolute position on the function stack where the function is stored
-    pub fun_stackpos: usize,
-    /// The argument names as StringIDs
-    pub argnames: Vec<Sid>,
-    /// The function body
-    pub body: Rc<BlockScope>,
-}
-
-/// Ast Node for a variable declaration
-#[derive(Debug, PartialEq, Eq, Clone)]
-pub struct VarDecl {
-    /// The variable name as StringID, stored in the stringstore
-    pub name: Sid,
-    /// The absolute position on the variable stack where the variable is stored
-    pub var_stackpos: usize,
-    /// The right hand side that generates the initial value for the variable
-    pub rhs: Expression,
-}
-
-/// Ast Node for the possible Statement variants
-#[derive(Debug, PartialEq, Eq, Clone)]
-pub enum Statement {
-    /// Return from a function with the given result value as an expression
-    Return(Expression),
-    /// Break out of the current loop
-    Break,
-    /// End the current loop iteration early and continue with the next loop iteration
-    Continue,
-    /// A variable declaration
-    Declaration(VarDecl),
-    /// A function declaration
-    FunDeclare(FunDecl),
-    /// A simple expression. This could be a function call or an assignment for example
-    Expr(Expression),
-    /// A freestanding block scope
-    Block(BlockScope),
-    /// A loop
-    Loop(Loop),
-    /// An if
-    If(If),
-    /// A print statement that will output the value of the given expression to the terminal
-    Print(Expression),
-}
-
-/// A number of statements that form a block of code together
-pub type BlockScope = Vec<Statement>;
-
-/// A full abstract syntax tree
-#[derive(Clone, Default)]
-pub struct Ast {
-    /// The stringstore contains the actual string values which are replaced with StringIDs in the
-    /// Ast. So this is needed to get the actual strings later
-    pub stringstore: StringStore,
-    /// The main (top-level) code given as a number of statements
-    pub main: BlockScope,
-}
-
-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::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/astoptimizer.rs

@@ -1,116 +0,0 @@
-use crate::ast::{Ast, BlockScope, Expression, If, Loop, Statement, BinOpType, UnOpType, VarDecl};
-
-/// A trait that allows to optimize an abstract syntax tree
-pub trait AstOptimizer {
-    /// Consume an abstract syntax tree and return an ast that has the same functionality but with
-    /// optional optimizations.
-    fn optimize(ast: Ast) -> Ast;
-}
-
-/// A very simple optimizer that applies trivial optimizations like precalculation expressions that 
-/// have only literals as operands
-pub struct SimpleAstOptimizer;
-
-impl AstOptimizer for SimpleAstOptimizer {
-    fn optimize(mut ast: Ast) -> Ast {
-        Self::optimize_block(&mut ast.main);
-        ast
-    }
-}
-
-impl SimpleAstOptimizer {
-    fn optimize_block(block: &mut BlockScope) {
-        for stmt in block {
-            match stmt {
-                Statement::Expr(expr) => Self::optimize_expr(expr),
-                Statement::Block(block) => Self::optimize_block(block),
-                Statement::Loop(Loop {
-                    condition,
-                    advancement,
-                    body,
-                }) => {
-                    if let Some(condition) = condition {
-                        Self::optimize_expr(condition);
-                    }
-                    if let Some(advancement) = advancement {
-                        Self::optimize_expr(advancement)
-                    }
-                    Self::optimize_block(body);
-                }
-                Statement::If(If {
-                    condition,
-                    body_true,
-                    body_false,
-                }) => {
-                    Self::optimize_expr(condition);
-                    Self::optimize_block(body_true);
-                    Self::optimize_block(body_false);
-                }
-                Statement::Print(expr) => Self::optimize_expr(expr),
-                Statement::Declaration(VarDecl { name: _, var_stackpos: _, rhs}) => Self::optimize_expr(rhs),
-                Statement::FunDeclare(_) => (),
-                Statement::Return(expr) => Self::optimize_expr(expr),
-                Statement::Break | Statement::Continue => (),
-            }
-        }
-    }
-
-    fn optimize_expr(expr: &mut Expression) {
-        match expr {
-            Expression::BinOp(bo, lhs, rhs) => {
-                Self::optimize_expr(lhs);
-                Self::optimize_expr(rhs);
-
-                // Precalculate binary operations that consist of 2 literals. No need to do this at 
-                // runtime, as all parts of the calculation are known at *compiletime* / parsetime.
-                match (lhs.as_mut(), rhs.as_mut()) {
-                    (Expression::I64(lhs), Expression::I64(rhs)) => {
-                        let new_expr = match bo {
-                            BinOpType::Add => Expression::I64(*lhs + *rhs),
-                            BinOpType::Mul => Expression::I64(*lhs * *rhs),
-                            BinOpType::Sub => Expression::I64(*lhs - *rhs),
-                            BinOpType::Div => Expression::I64(*lhs / *rhs),
-                            BinOpType::Mod => Expression::I64(*lhs % *rhs),
-                            BinOpType::BOr => Expression::I64(*lhs | *rhs),
-                            BinOpType::BAnd => Expression::I64(*lhs & *rhs),
-                            BinOpType::BXor => Expression::I64(*lhs ^ *rhs),
-                            BinOpType::LAnd => Expression::I64(if (*lhs != 0) && (*rhs != 0) { 1 } else { 0 }),
-                            BinOpType::LOr => Expression::I64(if (*lhs != 0) || (*rhs != 0) { 1 } else { 0 }),
-                            BinOpType::Shr => Expression::I64(*lhs >> *rhs),
-                            BinOpType::Shl => Expression::I64(*lhs << *rhs),
-                            BinOpType::EquEqu => Expression::I64(if lhs == rhs { 1 } else { 0 }),
-                            BinOpType::NotEqu => Expression::I64(if lhs != rhs { 1 } else { 0 }),
-                            BinOpType::Less => Expression::I64(if lhs < rhs { 1 } else { 0 }),
-                            BinOpType::LessEqu => Expression::I64(if lhs <= rhs { 1 } else { 0 }),
-                            BinOpType::Greater => Expression::I64(if lhs > rhs { 1 } else { 0 }),
-                            BinOpType::GreaterEqu => Expression::I64(if lhs >= rhs { 1 } else { 0 }),
-            
-                            BinOpType::Assign => unreachable!(),
-                        };
-                        *expr = new_expr;
-                    },
-                    _ => ()
-                }
-
-            }
-            Expression::UnOp(uo, operand) => {
-                Self::optimize_expr(operand);
-
-                // Precalculate unary operations just like binary ones
-                match operand.as_mut() {
-                    Expression::I64(val) => {
-                        let new_expr = match uo {
-                            UnOpType::Negate => Expression::I64(-*val),
-                            UnOpType::BNot => Expression::I64(!*val),
-                            UnOpType::LNot => Expression::I64(if *val == 0 { 1 } else { 0 }),
-                        };
-                        *expr = new_expr;
-                    }
-                    _ => (),
-                }
-            }
-            _ => (),
-        }
-
-    }
-}

src/bytecode.rs

@@ -0,0 +1,211 @@
+use std::collections::HashMap;
+
+use crate::ast::{Ast, Expr, Stmt, BinOpType};
+
+type OpcodeSize = u32;
+
+#[repr(u32)]
+#[derive(Debug, Clone, Copy)]
+pub enum OP {
+    Push,
+    Pop,
+    Load,
+    Store,
+
+    Add,
+    Subtract,
+    Multiply,
+    Divide,
+    Modulo,           
+    BOr,
+    BAnd,
+    BXor,
+    Shl,
+    Shr,
+
+    Eq,
+    Neq,
+
+    Gt,
+    Ge,
+    Lt,
+    Le,
+
+    Jump,
+
+    JumpTrue,
+
+    JumpFalse,
+
+    Print,
+
+    DbgPrint,
+}
+
+#[derive(Debug, Default)]
+pub struct Compiler {
+    ops: Vec<u32>,
+    global_vars: HashMap<String, u64>,
+}
+
+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 as OpcodeSize);
+                }
+                Stmt::Let(name, rhs) => {
+                    let id = self.global_vars.len() as u64;
+                    self.global_vars.insert(name.clone(), id);
+
+                    self.compile_expr(rhs);
+                    self.gen_store(id);
+                }
+                Stmt::While(cond, body) => {
+                    let idx_start = self.ops.len();
+                    self.compile_expr(cond);
+
+                    self.ops.push(OP::JumpFalse as OpcodeSize);
+                    let idx_jmp = self.ops.len();
+                    self.gen_i64(0);
+
+                    self.compile(body);
+
+                    self.ops.push(OP::Jump as OpcodeSize);
+                    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::JumpFalse as OpcodeSize);
+                    let idx_if = self.ops.len();
+                    self.gen_i64(0);
+
+                    self.compile(if_block);
+
+                    self.ops.push(OP::Jump as OpcodeSize);
+                    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::DbgPrint as OpcodeSize);
+                }
+                Stmt::Print(expr) => {
+                    self.compile_expr(expr);
+                    self.ops.push(OP::Print as OpcodeSize);
+                }
+            }
+        }
+    }
+
+    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 as OpcodeSize);
+                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 as OpcodeSize),
+            BinOpType::Sub => self.ops.push(OP::Subtract as OpcodeSize),
+            BinOpType::Mul => self.ops.push(OP::Multiply as OpcodeSize),
+            BinOpType::Div => self.ops.push(OP::Divide as OpcodeSize),
+            BinOpType::Mod => self.ops.push(OP::Modulo as OpcodeSize),
+            BinOpType::BOr => self.ops.push(OP::BOr as OpcodeSize),
+            BinOpType::BAnd => self.ops.push(OP::BAnd as OpcodeSize),
+            BinOpType::BXor => self.ops.push(OP::BXor as OpcodeSize),
+            BinOpType::Shl => self.ops.push(OP::Shl as OpcodeSize),
+            BinOpType::Shr => self.ops.push(OP::Shr as OpcodeSize),
+            BinOpType::Equ => self.ops.push(OP::Eq as OpcodeSize),
+            BinOpType::Neq => self.ops.push(OP::Neq as OpcodeSize),
+            BinOpType::Gt => self.ops.push(OP::Gt as OpcodeSize),
+            BinOpType::Ge => self.ops.push(OP::Ge as OpcodeSize),
+            BinOpType::Lt => self.ops.push(OP::Lt as OpcodeSize),
+            BinOpType::Le => self.ops.push(OP::Le as OpcodeSize),
+            BinOpType::Assign => unreachable!(),
+        }
+    }
+
+    fn gen_i64(&mut self, val: i64) {
+        // for i in 0 .. 8 {
+        //     self.ops.push(((val >> i*8) & 0xff) as OpcodeSize);
+        // }
+        for i in 0 .. 2 {
+            self.ops.push(((val >> i*32) & 0xffffffff) as OpcodeSize);
+        }
+    }
+
+    fn overwrite_i64(&mut self, idx: usize, val: i64) {
+        // for i in 0 .. 8 {
+        //     self.ops[idx+i] = ((val >> i*8) & 0xff) as OpcodeSize;
+        // }
+        for i in 0 .. 2 {
+            self.ops[idx+i] = ((val >> i*32) & 0xffffffff) as OpcodeSize;
+        }
+    }
+
+    fn gen_load(&mut self, addr: u64) {
+        self.ops.push(OP::Load as OpcodeSize);
+        self.gen_i64(addr as i64)
+    }
+
+    fn gen_store(&mut self, addr: u64) {
+        self.ops.push(OP::Store as OpcodeSize);
+        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

@@ -1,553 +1,175 @@
-use std::{cell::RefCell, rc::Rc};
+use std::{collections::HashMap, fmt::Display, rc::Rc};
-use thiserror::Error;
 
 use crate::{
-    ast::{Ast, BinOpType, BlockScope, Expression, FunDecl, If, Statement, UnOpType},
+    ast::{Ast, BinOpType, Expr, Stmt, UnOpType},
-    astoptimizer::{AstOptimizer, SimpleAstOptimizer},
     lexer::lex,
-    nice_panic,
     parser::parse,
-    stringstore::{Sid, StringStore},
 };
 
-/// Runtime errors that can occur during execution
-#[derive(Debug, Error)]
-pub enum RuntimeError {
-    #[error("Invalid array Index: {0:?}")]
-    InvalidArrayIndex(Value),
-
-    #[error("Variable used but not declared: {0}")]
-    VarUsedNotDeclared(String),
-
-    #[error("Can't index into non-array variable: {0}")]
-    TryingToIndexNonArray(String),
-
-    #[error("Invalid value type for unary operation: {0:?}")]
-    UnOpInvalidType(Value),
-
-    #[error("Incompatible binary operations. Operands don't match: {0:?} and {1:?}")]
-    BinOpIncompatibleTypes(Value, Value),
-
-    #[error("Array access out of bounds: Accessed {0}, size is {1}")]
-    ArrayOutOfBounds(usize, usize),
-
-    #[error("Division by zero")]
-    DivideByZero,
-
-    #[error("Invalid number of arguments for function {0}. Expected {1}, got {2}")]
-    InvalidNumberOfArgs(String, usize, usize),
-}
-
-/// Possible variants for the values
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum Value {
-    /// 64-bit integer value
     I64(i64),
-    /// String value
+    Str(Rc<String>),
-    String(Sid),
-    /// Array value
-    Array(Rc<RefCell<Vec<Value>>>),
-    /// Void value
-    Void,
 }
 
-/// The exit type of a block. When a block ends, the exit type specified why the block ended.
-#[derive(Debug, PartialEq, Eq, Clone)]
-pub enum BlockExit {
-    /// Normal exit when the block just ends normally (no returns / breaks / continues / etc.)
-    Normal,
-    /// The block ended through a break statement. This will be propagated up to the next loop
-    /// and cause it to fully terminate
-    Break,
-    /// The block ended through a continue statement. This will be propagated up to the next loop
-    /// and cause it to start the next iteration
-    Continue,
-    /// The block ended through a return statement. This will propagate up to the next function
-    /// body end
-    Return(Value),
-}
-
-#[derive(Default)]
 pub struct Interpreter {
-    /// Run the SimpleAstOptimizer over the Ast before executing
+    /// The variable table maps all variables by their names to their values
-    pub optimize_ast: bool,
+    vartable: HashMap<String, Value>,
-
-    /// Print the tokens after lexing
-    pub print_tokens: bool,
-    /// Print the ast after parsing
-    pub print_ast: bool,
-
-    /// Capture the output values of print statements instead of printing them to the terminal
-    pub capture_output: bool,
-    /// The stored values that were captured
-    output: Vec<Value>,
-
-    /// Variable table stores the runtime values of variables as a stack
-    vartable: Vec<Value>,
-
-    /// Function table stores the functions during runtime as a stack
-    funtable: Vec<FunDecl>,
-
-    /// The stringstore contains all strings used throughout the program
-    stringstore: StringStore,
 }
 
 impl Interpreter {
-    /// Create a new Interpreter
     pub fn new() -> Self {
-        Self {
+        let vartable = HashMap::new();
-            optimize_ast: true,
+        Self { vartable }
-            ..Self::default()
-        }
     }
 
-    /// Get the captured output
+    pub fn run_text(&mut self, code: &str, print_tokens: bool, print_ast: bool) {
-    pub fn output(&self) -> &[Value] {
+        let tokens = lex(code);
-        &self.output
+        if print_tokens {
-    }
-
-    /// Try to retrieve a variable value from the varstack. The idx is the index from the back of
-    /// the stack. So 0 is the last value, not the first
-    fn get_var(&self, idx: usize) -> Option<Value> {
-        self.vartable.get(self.vartable.len() - idx - 1).cloned()
-    }
-
-    /// Try to retrieve a mutable reference to a variable value from the varstack. The idx is the
-    /// index from the back of the stack. So 0 is the last value, not the first
-    fn get_var_mut(&mut self, idx: usize) -> Option<&mut Value> {
-        let idx = self.vartable.len() - idx - 1;
-        self.vartable.get_mut(idx)
-    }
-
-    /// Lex, parse and then run the given sourecode. This will terminate the program when an error
-    /// occurs and print an appropriate error message.
-    pub fn run_str(&mut self, code: &str) {
-        // Lex the tokens
-        let tokens = match lex(code) {
-            Ok(tokens) => tokens,
-            Err(e) => nice_panic!("Lexing error: {}", e),
-        };
-
-        if self.print_tokens {
             println!("Tokens: {:?}", tokens);
         }
-
+        let ast = parse(tokens);
-        // Parse the ast
+        if print_ast {
-        let ast = match parse(tokens) {
+            println!("Ast:\n{:#?}", ast);
-            Ok(ast) => ast,
-            Err(e) => nice_panic!("Parsing error: {}", e),
-        };
-
-        // Run the ast
-        match self.run_ast(ast) {
-            Ok(_) => (),
-            Err(e) => nice_panic!("Runtime error: {}", e),
         }
+        self.run(&ast);
     }
 
-    /// Execute the given Ast within the interpreter
+    pub fn run(&mut self, prog: &Ast) {
-    pub fn run_ast(&mut self, mut ast: Ast) -> Result<(), RuntimeError> {
+        for stmt in &prog.prog {
-        // Optimize the ast
-        if self.optimize_ast {
-            ast = SimpleAstOptimizer::optimize(ast);
-        }
-
-        if self.print_ast {
-            println!("{:#?}", ast.main);
-        }
-
-        // Take over the stringstore of the given ast
-        self.stringstore = ast.stringstore;
-
-        // Run the top level block (the main)
-        self.run_block(&ast.main)?;
-        Ok(())
-    }
-
-    /// Run all statements in the given block
-    pub fn run_block(&mut self, prog: &BlockScope) -> Result<BlockExit, RuntimeError> {
-        self.run_block_fp_offset(prog, 0)
-    }
-
-    /// Same as run_block, but with an additional framepointer offset. This allows to free more
-    /// values from the stack than normally and can be used when passing arguments inside a
-    /// function body scope from the outside
-    pub fn run_block_fp_offset(
-        &mut self,
-        prog: &BlockScope,
-        framepointer_offset: usize,
-    ) -> Result<BlockExit, RuntimeError> {
-        let framepointer = self.vartable.len() - framepointer_offset;
-
-        let mut block_exit = BlockExit::Normal;
-
-        'blockloop: for stmt in prog {
             match stmt {
-                Statement::Break => return Ok(BlockExit::Break),
+                Stmt::Expr(expr) => {
-                Statement::Continue => return Ok(BlockExit::Continue),
+                    self.resolve_expr(expr);
-
-                Statement::Return(expr) => {
-                    let val = self.resolve_expr(expr)?;
-
-                    block_exit = BlockExit::Return(val);
-                    break 'blockloop;
                 }
-
+                Stmt::DbgPrint(expr) => {
-                Statement::Expr(expr) => {
+                    let result = self.resolve_expr(expr);
-                    self.resolve_expr(expr)?;
+                    println!("{:?}", result);
                 }
-
+                Stmt::Print(expr) => {
-                Statement::Declaration(decl) => {
+                    let result = self.resolve_expr(expr);
-                    let rhs = self.resolve_expr(&decl.rhs)?;
+                    print!("{}", result);
-                    self.vartable.push(rhs);
                 }
+                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);
 
-                Statement::Block(block) => match self.run_block(block)? {
-                    // Propagate return, continue and break
-                    be @ (BlockExit::Return(_) | BlockExit::Continue | BlockExit::Break) => {
-                        block_exit = be;
-                        break 'blockloop;
-                    }
-                    _ => (),
-                },
-
-                Statement::Loop(looop) => {
-                    // loop runs as long condition != 0
                     loop {
-                        // Check the loop condition
+                        // Check condition
-                        if let Some(condition) = &looop.condition {
+                        match self.resolve_expr(condition) {
-                            if matches!(self.resolve_expr(condition)?, Value::I64(0)) {
+                            Value::I64(val) if val == 0 => break,
-                                break;
+                            Value::I64(_) => (),
-                            }
+
+                            Value::Str(text) if text.is_empty() => break,
+                            Value::Str(_) => (),
                         }
 
-                        // Run the body
+                        // Execute loop body
-                        let be = self.run_block(&looop.body)?;
+                        self.run(body);
-                        match be {
-                            // Propagate return
-                            be @ BlockExit::Return(_) => {
-                                block_exit = be;
-                                break 'blockloop;
-                            }
-                            BlockExit::Break => break,
-                            BlockExit::Continue | BlockExit::Normal => (),
-                        }
 
-                        // Run the advancement
+                        // Execute advancement
-                        if let Some(adv) = &looop.advancement {
+                        self.resolve_expr(advance);
-                            self.resolve_expr(&adv)?;
-                        }
                     }
                 }
+                Stmt::While(condition, body) => {
+                    loop {
+                        // Check condition
+                        match self.resolve_expr(condition) {
+                            Value::I64(val) if val == 0 => break,
+                            Value::I64(_) => (),
 
-                Statement::Print(expr) => {
+                            Value::Str(text) if text.is_empty() => break,
-                    let result = self.resolve_expr(expr)?;
+                            Value::Str(_) => (),
+                        }
 
-                    if self.capture_output {
+                        // Execute loop body
-                        self.output.push(result)
+                        self.run(body);
+                    }
+                }
+                Stmt::If(condition, body_if, body_else) => {
+                    if matches!(self.resolve_expr(condition), Value::I64(0)) {
+                        self.run(body_else);
                     } else {
-                        print!("{}", self.value_to_string(&result));
+                        self.run(body_if);
                     }
                 }
-
-                Statement::If(If {
-                    condition,
-                    body_true,
-                    body_false,
-                }) => {
-                    // Run the right block depending on the conditions result being 0 or not 
-                    let exit = if matches!(self.resolve_expr(condition)?, Value::I64(0)) {
-                        self.run_block(body_false)?
-                    } else {
-                        self.run_block(body_true)?
-                    };
-
-                    match exit {
-                        // Propagate return, continue and break
-                        be @ (BlockExit::Return(_) | BlockExit::Continue | BlockExit::Break) => {
-                            block_exit = be;
-                            break 'blockloop;
-                        }
-                        _ => (),
-                    }
-                }
-
-                Statement::FunDeclare(fundec) => {
-                    self.funtable.push(fundec.clone());
-                }
-            }
-        }
-
-        self.vartable.truncate(framepointer);
-
-        Ok(block_exit)
-    }
-
-    /// Execute the given expression to retrieve the resulting value
-    fn resolve_expr(&mut self, expr: &Expression) -> Result<Value, RuntimeError> {
-        let val = match expr {
-            Expression::I64(val) => Value::I64(*val),
-            Expression::ArrayLiteral(size) => {
-                let size = match self.resolve_expr(size)? {
-                    Value::I64(size) if !size.is_negative() => size,
-                    val => return Err(RuntimeError::InvalidArrayIndex(val)),
-                };
-                Value::Array(Rc::new(RefCell::new(vec![Value::I64(0); size as usize])))
-            }
-            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, idx) => self.resolve_var(*name, *idx)?,
-            Expression::ArrayAccess(name, idx, arr_idx) => {
-                self.resolve_array_access(*name, *idx, arr_idx)?
-            }
-
-            Expression::FunCall(fun_name, fun_stackpos, args) => {
-                let args_len = args.len();
-
-                // All of the arg expressions must be resolved before pushing the vars on the stack,
-                // otherwise the stack positions are incorrect while resolving
-                let args = args
-                    .iter()
-                    .map(|arg| self.resolve_expr(arg))
-                    .collect::<Vec<_>>();
-                for arg in args {
-                    self.vartable.push(arg?);
-                }
-
-                // Function existance has been verified in the parser, so unwrap here shouldn't fail
-                let expected_num_args = self.funtable.get(*fun_stackpos).unwrap().argnames.len();
-
-                // Check if the number of provided arguments matches the number of expected arguments
-                if expected_num_args != args_len {
-                    let fun_name = self
-                        .stringstore
-                        .lookup(*fun_name)
-                        .cloned()
-                        .unwrap_or("<unknown>".to_string());
-                    return Err(RuntimeError::InvalidNumberOfArgs(
-                        fun_name,
-                        expected_num_args,
-                        args_len,
-                    ));
-                }
-
-                // Run the function body and return the BlockExit type
-                match self.run_block_fp_offset(
-                    &Rc::clone(&self.funtable.get(*fun_stackpos).unwrap().body),
-                    expected_num_args,
-                )? {
-                    BlockExit::Normal | BlockExit::Continue | BlockExit::Break => Value::Void,
-                    BlockExit::Return(val) => val,
-                }
-            }
-        };
-
-        Ok(val)
-    }
-
-    /// Retrive the value of a given array at the specified index from the varstack. The name is
-    /// given as a StringID and is used to reference the variable name in case of an error. The
-    /// idx is the stackpos where the array variable should be located and the arr_idx is the
-    /// actual array access index, given as an expression.
-    fn resolve_array_access(
-        &mut self,
-        name: Sid,
-        idx: usize,
-        arr_idx: &Expression,
-    ) -> Result<Value, RuntimeError> {
-        // Resolve the array index into a value and check if it is a valid array index
-        let arr_idx = match self.resolve_expr(arr_idx)? {
-            Value::I64(size) if !size.is_negative() => size,
-            val => return Err(RuntimeError::InvalidArrayIndex(val)),
-        };
-
-        // Get the array value
-        let val = match self.get_var(idx) {
-            Some(val) => val,
-            None => {
-                return Err(RuntimeError::VarUsedNotDeclared(
-                    self.stringstore
-                        .lookup(name)
-                        .cloned()
-                        .unwrap_or_else(|| "<unknown>".to_string()),
-                ))
-            }
-        };
-
-        // Make sure it is an array
-        let arr = match val {
-            Value::Array(arr) => arr,
-            _ => {
-                return Err(RuntimeError::TryingToIndexNonArray(
-                    self.stringstore
-                        .lookup(name)
-                        .cloned()
-                        .unwrap_or_else(|| "<unknown>".to_string()),
-                ))
-            }
-        };
-
-        // Get the value of the requested cell inside the array
-        let arr = arr.borrow();
-        arr.get(arr_idx as usize)
-            .cloned()
-            .ok_or(RuntimeError::ArrayOutOfBounds(arr_idx as usize, arr.len()))
-    }
-
-    /// Retrive the value of a given variable from the varstack. The name is given as a StringID
-    /// and is used to reference the variable name in case of an error. The idx is the stackpos
-    /// where the variable should be located
-    fn resolve_var(&mut self, name: Sid, idx: usize) -> Result<Value, RuntimeError> {
-        match self.get_var(idx) {
-            Some(val) => Ok(val),
-            None => {
-                return Err(RuntimeError::VarUsedNotDeclared(
-                    self.stringstore
-                        .lookup(name)
-                        .cloned()
-                        .unwrap_or_else(|| "<unknown>".to_string()),
-                ))
             }
         }
     }
 
-    /// Execute a unary operation and get the resulting value
+    fn resolve_expr(&mut self, expr: &Expr) -> Value {
-    fn resolve_unop(&mut self, uo: &UnOpType, operand: &Expression) -> Result<Value, RuntimeError> {
+        match expr {
-        // Recursively resolve the operands expression into an actual value
+            Expr::I64(val) => Value::I64(*val),
-        let operand = self.resolve_expr(operand)?;
+            Expr::Str(name) => Value::Str(name.clone()),
-
+            Expr::BinOp(bo, lhs, rhs) => self.resolve_binop(bo, &lhs, &rhs),
-        // Perform the correct operation, considering the operation and value type
+            Expr::UnOp(uo, val) => self.resolve_unop(uo, &val),
-        Ok(match (operand, uo) {
+            Expr::Ident(name) => match self.vartable.get(name) {
-            (Value::I64(val), UnOpType::Negate) => Value::I64(-val),
+                None => panic!("Runtime error: Use of undeclared variable '{}'", name),
-            (Value::I64(val), UnOpType::BNot) => Value::I64(!val),
+                Some(val) => val.clone(),
-            (Value::I64(val), UnOpType::LNot) => Value::I64(if val == 0 { 1 } else { 0 }),
+            },
-            (val, _) => return Err(RuntimeError::UnOpInvalidType(val)),
+        }
-        })
     }
 
-    /// Execute a binary operation and get the resulting value
+    fn resolve_binop(&mut self, bo: &BinOpType, lhs: &Expr, rhs: &Expr) -> Value {
-    fn resolve_binop(
+        // Treat assignment separate from the other expressions
-        &mut self,
+        if matches!(bo, BinOpType::Assign) {
-        bo: &BinOpType,
+            match lhs {
-        lhs: &Expression,
+                Expr::Ident(name) => {
-        rhs: &Expression,
+                    let rhs = self.resolve_expr(rhs);
-    ) -> Result<Value, RuntimeError> {
+                    self.vartable.get_mut(name).map(|var| *var = rhs.clone());
-        let rhs = self.resolve_expr(rhs)?;
+                    return rhs;
-
-        // Handle assignments separate from the other binary operations
-        match (&bo, &lhs) {
-            // Normal variable assignment
-            (BinOpType::Assign, Expression::Var(name, idx)) => {
-                // Get the variable mutably and assign the right hand side value
-                match self.get_var_mut(*idx) {
-                    Some(val) => *val = rhs.clone(),
-                    None => {
-                        return Err(RuntimeError::VarUsedNotDeclared(
-                            self.stringstore
-                                .lookup(*name)
-                                .cloned()
-                                .unwrap_or_else(|| "<unknown>".to_string()),
-                        ))
-                    }
                 }
-
+                _ => panic!("Runtime error: Left hand side of assignment must be an identifier"),
-                return Ok(rhs);
             }
-            // Array index assignment
-            (BinOpType::Assign, Expression::ArrayAccess(name, idx, arr_idx)) => {
-                // Calculate the array index
-                let arr_idx = match self.resolve_expr(arr_idx)? {
-                    Value::I64(size) if !size.is_negative() => size,
-                    val => return Err(RuntimeError::InvalidArrayIndex(val)),
-                };
-
-                // Get the mutable ref to the array variable
-                let val = match self.get_var_mut(*idx) {
-                    Some(val) => val,
-                    None => {
-                        return Err(RuntimeError::VarUsedNotDeclared(
-                            self.stringstore
-                                .lookup(*name)
-                                .cloned()
-                                .unwrap_or_else(|| "<unknown>".to_string()),
-                        ))
-                    }
-                };
-
-                // Verify that it actually is an array
-                match val {
-                    // Assign the right hand side value to the array it the given index
-                    Value::Array(arr) => arr.borrow_mut()[arr_idx as usize] = rhs.clone(),
-                    _ => {
-                        return Err(RuntimeError::TryingToIndexNonArray(
-                            self.stringstore
-                                .lookup(*name)
-                                .cloned()
-                                .unwrap_or_else(|| "<unknown>".to_string()),
-                        ))
-                    }
-                }
-
-                return Ok(rhs);
-            }
-            _ => (),
         }
 
-        // This code is only executed if the binop is not an assignment as the assignments return
+        let lhs = self.resolve_expr(lhs);
-        // early
+        let rhs = self.resolve_expr(rhs);
 
-        // Resolve the left hand side to the value
+        match (lhs, rhs) {
-        let lhs = self.resolve_expr(lhs)?;
-
-        // Perform the appropriate calculations considering the operation type and datatypes of the
-        // two values
-        let result = match (lhs, rhs) {
             (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 => {
+                BinOpType::Div => Value::I64(lhs / rhs),
-                    Value::I64(lhs.checked_div(rhs).ok_or(RuntimeError::DivideByZero)?)
+                BinOpType::Mod => Value::I64(lhs % rhs),
-                }
-                BinOpType::Mod => {
-                    Value::I64(lhs.checked_rem(rhs).ok_or(RuntimeError::DivideByZero)?)
-                }
                 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::EquEqu => Value::I64(if lhs == rhs { 1 } else { 0 }),
+                BinOpType::Equ => Value::I64(if lhs == rhs { 1 } else { 0 }),
-                BinOpType::NotEqu => Value::I64(if lhs != rhs { 1 } else { 0 }),
+                BinOpType::Neq => Value::I64(if lhs != rhs { 1 } else { 0 }),
-                BinOpType::Less => Value::I64(if lhs < rhs { 1 } else { 0 }),
+                BinOpType::Gt => Value::I64(if lhs > rhs { 1 } else { 0 }),
-                BinOpType::LessEqu => Value::I64(if lhs <= rhs { 1 } else { 0 }),
+                BinOpType::Ge => Value::I64(if lhs >= rhs { 1 } else { 0 }),
-                BinOpType::Greater => Value::I64(if lhs > rhs { 1 } else { 0 }),
+                BinOpType::Lt => Value::I64(if lhs < rhs { 1 } else { 0 }),
-                BinOpType::GreaterEqu => Value::I64(if lhs >= rhs { 1 } else { 0 }),
+                BinOpType::Le => Value::I64(if lhs <= rhs { 1 } else { 0 }),
-
                 BinOpType::Assign => unreachable!(),
             },
-            (lhs, rhs) => return Err(RuntimeError::BinOpIncompatibleTypes(lhs, rhs)),
+            _ => panic!("Value types are not compatible"),
-        };
+        }
-
-        Ok(result)
     }
 
-    /// Get a string representation of the given value. This uses the interpreters StringStore to
+    fn resolve_unop(&mut self, uo: &UnOpType, val: &Expr) -> Value {
-    /// retrive the text values of Strings
+        let val = self.resolve_expr(val);
-    fn value_to_string(&self, val: &Value) -> String {
         match val {
-            Value::I64(val) => format!("{}", val),
+            Value::I64(val) => match uo {
-            Value::Array(val) => format!("{:?}", val.borrow()),
+                UnOpType::Neg => Value::I64(-val),
-            Value::String(text) => format!(
+            },
-                "{}",
+            _ => panic!("Invalid unary operation for type"),
-                self.stringstore
+        }
-                    .lookup(*text)
+    }
-                    .unwrap_or(&"<invalid string>".to_string())
+}
-            ),
+
-            Value::Void => format!("void"),
+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),
         }
     }
 }
@@ -555,34 +177,27 @@ impl Interpreter {
 #[cfg(test)]
 mod test {
     use super::{Interpreter, Value};
-    use crate::ast::{BinOpType, Expression};
+    use crate::ast::{BinOpType, Expr};
 
-    /// Simple test to check if a simple expression is executed properly.
-    /// Full system tests from lexing to execution can be found in `lib.rs`
     #[test]
     fn test_interpreter_expr() {
         // Expression: 1 + 2 * 3 + 4
         // With precedence: (1 + (2 * 3)) + 4
-        let ast = Expression::BinOp(
+        let ast = Expr::BinOp(
             BinOpType::Add,
-            Expression::BinOp(
+            Expr::BinOp(
                 BinOpType::Add,
-                Expression::I64(1).into(),
+                Expr::I64(1).into(),
-                Expression::BinOp(
+                Expr::BinOp(BinOpType::Mul, Expr::I64(2).into(), Expr::I64(3).into()).into(),
-                    BinOpType::Mul,
-                    Expression::I64(2).into(),
-                    Expression::I64(3).into(),
-                )
-                .into(),
             )
             .into(),
-            Expression::I64(4).into(),
+            Expr::I64(4).into(),
         );
 
         let expected = Value::I64(11);
 
         let mut interpreter = Interpreter::new();
-        let actual = interpreter.resolve_expr(&ast).unwrap();
+        let actual = interpreter.resolve_expr(&ast);
 
         assert_eq!(expected, actual);
     }

src/lexer.rs

@@ -1,131 +1,115 @@
 use std::{iter::Peekable, str::Chars};
-use thiserror::Error;
 
-use crate::{token::Token, T};
+use crate::token::{Keyword, Literal, Token};
-
-/// Errors that can occur while lexing a given string
-#[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) -> Result<Vec<Token>, LexErr> {
+pub fn lex(code: &str) -> Vec<Token> {
-    let lexer = Lexer::new(code);
+    let mut lexer = Lexer::new(code);
     lexer.lex()
 }
 
-/// The lexer is created from a reference to a sourcecode string and is consumed to create a token 
-/// buffer from that sourcecode.
 struct Lexer<'a> {
-    /// The sourcecode text as a peekable iterator over the chars. Peekable allows for look-ahead 
-    /// and the use of the Chars iterator allows to support unicode characters
     code: Peekable<Chars<'a>>,
-    /// The lexed tokens
-    tokens: Vec<Token>,
-    /// The sourcecode character that is currently being lexed
-    current_char: char,
 }
 
 impl<'a> Lexer<'a> {
-
-    /// Create a new lexer from the given sourcecode
     fn new(code: &'a str) -> Self {
         let code = code.chars().peekable();
-        let tokens = Vec::new();
+        Self { code }
-        let current_char = '\0';
-        Self {
-            code,
-            tokens,
-            current_char,
-        }
     }
 
-    /// Consume the lexer and try to lex the contained sourcecode into a token buffer
+    /// Advance to next character and return the removed char. If there is no next char, '\0'
-    fn lex(mut self) -> Result<Vec<Token>, LexErr> {
+    /// 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();
 
         loop {
-            self.current_char = self.next();
+            match self.next() {
-            // Match on the current and next character. This gives a 1-char look-ahead and
+                // End of text
-            // can be used to directly match 2-char tokens
+                '\0' => break,
-            match (self.current_char, self.peek()) {
-                // Stop lexing at EOF
-                ('\0', _) => break,
 
-                // Skip / ignore whitespace
+                // Skip whitespace
-                (' ' | '\t' | '\n' | '\r', _) => (),
+                ' ' | '\r' | '\n' | '\t' => (),
 
-                // Line comment. Consume every char until linefeed (next line)
+                // Handle tokens that span two characters
-                ('/', '/') => while !matches!(self.next(), '\n' | '\0') {},
+                '>' if matches!(self.peek(), '>') => {
+                    self.next();
+                    tokens.push(Token::Shr);
+                }
+                '<' if matches!(self.peek(), '<') => {
+                    self.next();
+                    tokens.push(Token::Shl);
+                }
+                '=' if matches!(self.peek(), '=') => {
+                    self.next();
+                    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);
+                }
 
-                // Double character tokens
+                // Handle tokens that span one character
-                ('>', '>') => self.push_tok_consume(T![>>]),
+                '+' => tokens.push(Token::Add),
-                ('<', '<') => self.push_tok_consume(T![<<]),
+                '-' => tokens.push(Token::Sub),
-                ('=', '=') => self.push_tok_consume(T![==]),
+                '*' => tokens.push(Token::Mul),
-                ('!', '=') => self.push_tok_consume(T![!=]),
+                '/' => tokens.push(Token::Div),
-                ('<', '=') => self.push_tok_consume(T![<=]),
+                '%' => tokens.push(Token::Mod),
-                ('>', '=') => self.push_tok_consume(T![>=]),
+                '|' => tokens.push(Token::BOr),
-                ('<', '-') => self.push_tok_consume(T![<-]),
+                '&' => tokens.push(Token::BAnd),
-                ('&', '&') => self.push_tok_consume(T![&&]),
+                '^' => tokens.push(Token::BXor),
-                ('|', '|') => self.push_tok_consume(T![||]),
+                '(' => 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),
 
-                // Single character tokens
+                // Handle special multicharacter tokens
-                (',', _) => self.push_tok(T![,]),
-                (';', _) => self.push_tok(T![;]),
-                ('+', _) => self.push_tok(T![+]),
-                ('-', _) => self.push_tok(T![-]),
-                ('*', _) => self.push_tok(T![*]),
-                ('/', _) => self.push_tok(T![/]),
-                ('%', _) => self.push_tok(T![%]),
-                ('|', _) => self.push_tok(T![|]),
-                ('&', _) => self.push_tok(T![&]),
-                ('^', _) => self.push_tok(T![^]),
-                ('(', _) => self.push_tok(T!['(']),
-                (')', _) => self.push_tok(T![')']),
-                ('~', _) => self.push_tok(T![~]),
-                ('<', _) => self.push_tok(T![<]),
-                ('>', _) => self.push_tok(T![>]),
-                ('=', _) => self.push_tok(T![=]),
-                ('{', _) => self.push_tok(T!['{']),
-                ('}', _) => self.push_tok(T!['}']),
-                ('!', _) => self.push_tok(T![!]),
-                ('[', _) => self.push_tok(T!['[']),
-                (']', _) => self.push_tok(T![']']),
 
-                // Special tokens with variable length
+                // Lex numbers
+                ch @ '0'..='9' => tokens.push(self.lex_number(ch)),
 
-                // Lex multiple characters together as numbers
+                // Lex strings
-                ('0'..='9', _) => self.lex_number()?,
+                '"' => tokens.push(self.lex_string()),
 
-                // Lex multiple characters together as a string
+                // Lex identifiers
-                ('"', _) => self.lex_str()?,
+                ch @ ('a'..='z' | 'A'..='Z' | '_') => tokens.push(self.lex_ident(ch)),
 
-                // Lex multiple characters together as identifier or keyword
+                // Any other character is unexpected
-                ('a'..='z' | 'A'..='Z' | '_', _) => self.lex_identifier()?,
+                ch => panic!("Lexer encountered unexpected char: '{}'", ch),
-
-                // Any character that was not handled otherwise is invalid
-                (ch, _) => Err(LexErr::UnexpectedChar(ch))?,
             }
         }
 
-        Ok(self.tokens)
+        tokens
     }
 
-    /// Lex multiple characters as a number until encountering a non numeric digit. The
+    fn lex_number(&mut self, first_char: char) -> Token {
-    /// successfully lexed i64 literal token is appended to the stored tokens.
+        let mut sval = String::from(first_char);
-    fn lex_number(&mut self) -> Result<(), LexErr> {
-        // String representation of the integer value
-        let mut sval = String::from(self.current_char);
 
         // Do as long as a next char exists and it is a numeric char
         loop {
@@ -143,171 +127,112 @@ impl<'a> Lexer<'a> {
             }
         }
 
-        // Try to convert the string representation of the value to i64. The error is mapped to
+        // TODO: We only added numeric chars to the string, but the conversion could still fail
-        // the appropriate LexErr
+        Token::Literal(Literal::I64(sval.parse().unwrap()))
-        let i64val = sval.parse().map_err(|_| LexErr::NumericParse(sval))?;
-
-        self.push_tok(T![i64(i64val)]);
-
-        Ok(())
     }
 
-    /// Lex characters as a string until encountering an unescaped closing doublequoute char '"'.
+    /// Lex an identifier from the character stream. The first char has to have been consumed
-    /// The successfully lexed string literal token is appended to the stored tokens.
+    /// from the stream already and is passed as an argument instead.
-    fn lex_str(&mut self) -> Result<(), LexErr> {
+    fn lex_ident(&mut self, first_char: char) -> Token {
-        // The opening " was consumed in match, so a fresh string can be used
+        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 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();
 
-        // Read all chars until encountering the closing "
+        let mut escape = false;
+
+        // Do as long as a next char exists and it is not '"'
         loop {
-            match self.peek() {
+            if escape {
-                // An unescaped doubleqoute ends the current string
+                escape = false;
-                '"' => break,
 
-                // If the end of file is reached while still waiting for '"', error out
+                // Escape characters
-                '\0' => Err(LexErr::MissingClosingString)?,
+                match self.next() {
-
+                    '\\' => text.push('\\'),
-                _ => match self.next() {
+                    'n' => text.push('\n'),
-                    // Backslash indicates an escaped character, so consume one more char and
+                    'r' => text.push('\r'),
-                    // treat it as the escaped char
+                    't' => text.push('\t'),
-                    '\\' => match self.next() {
+                    ch => panic!("Invalid string escape: '{:?}'", ch),
-                        'n' => text.push('\n'),
+                }
-                        'r' => text.push('\r'),
+            } else {
-                        't' => text.push('\t'),
+                match self.peek() {
-                        '\\' => text.push('\\'),
+                    // Doublequote '"' ends the string lexing
-                        '"' => text.push('"'),
+                    '"' => {
-                        // If the escaped char is not handled, it is unsupported and an error
+                        self.next();
-                        ch => Err(LexErr::InvalidStrEscape(ch))?,
+                        break;
-                    },
+                    }
-                    // All other characters are simply appended to the string
+                    // Backslash '\' escapes the next character
-                    ch => text.push(ch),
+                    '\\' => {
-                },
+                        self.next();
-            }
+                        escape = true;
-        }
+                    }
-
+
-        // Consume closing "
+                    // Reached end of text but didn't encounter closing doublequote '"'
-        self.next();
+                    '\0' => panic!("String is never terminated (missing '\"')"),
-
+
-        self.push_tok(T![str(text)]);
+                    _ => text.push(self.next()),
-
-        Ok(())
-    }
-
-    /// Lex characters from the text as an identifier. The successfully lexed ident or keyword
-    /// token is appended to the stored tokens.
-    fn lex_identifier(&mut self) -> Result<(), LexErr> {
-        let mut ident = String::from(self.current_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
+        Token::Literal(Literal::Str(text))
-        let token = match ident.as_str() {
-            "loop" => T![loop],
-            "print" => T![print],
-            "if" => T![if],
-            "else" => T![else],
-            "fun" => T![fun],
-            "return" => T![return],
-            "break" => T![break],
-            "continue" => T![continue],
-
-            // If it doesn't match a keyword, it is a normal identifier
-            _ => T![ident(ident)],
-        };
-
-        self.push_tok(token);
-
-        Ok(())
-    }
-
-    /// Push the given token into the stored tokens
-    fn push_tok(&mut self, token: Token) {
-        self.tokens.push(token);
-    }
-
-    /// Same as `push_tok` but also consumes the next token, removing it from the code iter. This
-    /// is useful when lexing double char tokens where the second token has only been peeked.
-    fn push_tok_consume(&mut self, token: Token) {
-        self.next();
-        self.tokens.push(token);
-    }
-
-    /// Advance to next character and return the removed char. When the end of the code is reached,
-    /// `'\0'` is returned. This is used instead of an Option::None since it allows for much 
-    /// shorter and cleaner code in the main loop. The `'\0'` character would not be valid anyways
-    fn next(&mut self) -> char {
-        self.code.next().unwrap_or('\0')
-    }
-
-    /// Get the next character without removing it. When the end of the code is reached,
-    /// `'\0'` is returned. This is used instead of an Option::None since it allows for much 
-    /// shorter and cleaner code in the main loop. The `'\0'` character would not be valid anyways
-    fn peek(&mut self) -> char {
-        self.code.peek().copied().unwrap_or('\0')
     }
 }
 
 #[cfg(test)]
 mod tests {
-    use crate::{lexer::lex, T};
+    use crate::token::Literal;
+
+    use super::{lex, Token};
 
-    /// A general test to check if the lexer actually lexes tokens correctly
     #[test]
     fn test_lexer() {
-        let code = r#"53+1-567_000 * / % | ~ ! < > & ^ ({[]});= <- >= <=
+        let code = "33   +5*2  + 4456467*2334+3 % - / << ^ | & >>";
-            == != && || << >> loop if else print my_123var "hello \t world\r\n\"\\""#;
         let expected = vec![
-            T![i64(53)],
+            Token::Literal(Literal::I64(33)),
-            T![+],
+            Token::Add,
-            T![i64(1)],
+            Token::Literal(Literal::I64(5)),
-            T![-],
+            Token::Mul,
-            T![i64(567_000)],
+            Token::Literal(Literal::I64(2)),
-            T![*],
+            Token::Add,
-            T![/],
+            Token::Literal(Literal::I64(4456467)),
-            T![%],
+            Token::Mul,
-            T![|],
+            Token::Literal(Literal::I64(2334)),
-            T![~],
+            Token::Add,
-            T![!],
+            Token::Literal(Literal::I64(3)),
-            T![<],
+            Token::Mod,
-            T![>],
+            Token::Sub,
-            T![&],
+            Token::Div,
-            T![^],
+            Token::Shl,
-            T!['('],
+            Token::BXor,
-            T!['{'],
+            Token::BOr,
-            T!['['],
+            Token::BAnd,
-            T![']'],
+            Token::Shr,
-            T!['}'],
-            T![')'],
-            T![;],
-            T![=],
-            T![<-],
-            T![>=],
-            T![<=],
-            T![==],
-            T![!=],
-            T![&&],
-            T![||],
-            T![<<],
-            T![>>],
-            T![loop],
-            T![if],
-            T![else],
-            T![print],
-            T![ident("my_123var".to_string())],
-            T![str("hello \t world\r\n\"\\".to_string())],
         ];
 
-        let actual = lex(code).unwrap();
+        let actual = lex(code);
         assert_eq!(expected, actual);
     }
 }

src/lib.rs

@@ -1,68 +1,7 @@
-pub mod ast;
-pub mod interpreter;
 pub mod lexer;
 pub mod parser;
+pub mod interpreter;
 pub mod token;
-pub mod stringstore;
+pub mod ast;
-pub mod astoptimizer;
+pub mod bytecode;
-pub mod util;
+pub mod vm;
-
-/// A bunch of full program tests using the example code programs as test subjects.
-#[cfg(test)]
-mod tests {
-    use crate::interpreter::{Interpreter, Value};
-    use std::fs::read_to_string;
-
-    /// Run a nek program with the given filename from the examples directory and assert the
-    /// captured output with the expected result. This only works if the program just outputs one
-    /// value as the result
-    fn run_example_check_single_i64_output(filename: &str, correct_result: i64) {
-        let mut interpreter = Interpreter::new();
-        // Enable output capturing. This captures all calls to `print`
-        interpreter.capture_output = true;
-
-        // Load and run the given program
-        let code = read_to_string(format!("examples/{filename}")).unwrap();
-        interpreter.run_str(&code);
-
-        // Compare the captured output with the expected value
-        let expected_output = [Value::I64(correct_result)];
-        assert_eq!(interpreter.output(), &expected_output);
-    }
-
-    #[test]
-    fn test_euler1() {
-        run_example_check_single_i64_output("euler1.nek", 233168);
-    }
-
-    #[test]
-    fn test_euler2() {
-        run_example_check_single_i64_output("euler2.nek", 4613732);
-    }
-
-    #[test]
-    fn test_euler3() {
-        run_example_check_single_i64_output("euler3.nek", 6857);
-    }
-
-    #[test]
-    fn test_euler4() {
-        run_example_check_single_i64_output("euler4.nek", 906609);
-    }
-
-    #[test]
-    fn test_euler5() {
-        run_example_check_single_i64_output("euler5.nek", 232792560);
-    }
-
-    #[test]
-    fn test_recursive_fib() {
-        run_example_check_single_i64_output("recursive_fib.nek", 832040);
-    }
-
-    #[test]
-    fn test_functions() {
-        run_example_check_single_i64_output("test_functions.nek", 69);
-    }
-}
-

src/main.rs

@@ -1,59 +1,63 @@
-use std::{env::args, fs, process::exit};
+use std::{env::args, io::Write};
 
-use nek_lang::{interpreter::Interpreter, nice_panic};
+use nek_lang::{interpreter::Interpreter, lexer::lex, parser::parse, bytecode::compile, vm::Vm};
 
-/// Cli configuration flags and arguments. This could be done with `clap`, but since only so few
-/// arguments are supported this seems kind of overkill.
 #[derive(Debug, Default)]
 struct CliConfig {
     print_tokens: bool,
     print_ast: bool,
-    no_optimizations: bool,
+    interactive: bool,
     file: Option<String>,
 }
 
 fn main() {
-    let mut conf = CliConfig::default();
+    let mut cfg = CliConfig::default();
 
-    // Go through all commandline arguments except the first (filename)
     for arg in args().skip(1) {
         match arg.as_str() {
-            "--token" | "-t" => conf.print_tokens = true,
+            "--tokens" | "-t" => cfg.print_tokens = true,
-            "--ast" | "-a" => conf.print_ast = true,
+            "--ast" | "-a" => cfg.print_ast = true,
-            "--no-opt" | "-n" => conf.no_optimizations = true,
+            "--interactive" | "-i" => cfg.interactive = true,
-            "--help" | "-h" => print_help(),
+            file if cfg.file.is_none() => cfg.file = Some(file.to_string()),
-            file if !arg.starts_with("-") && conf.file.is_none() => {
+            _ => panic!("Invalid argument: '{}'", arg),
-                conf.file = Some(file.to_string())
-            }
-            _ => nice_panic!("Error: Invalid argument '{}'", arg),
         }
     }
 
     let mut interpreter = Interpreter::new();
 
-    interpreter.print_tokens = conf.print_tokens;
+    if let Some(file) = &cfg.file {
-    interpreter.print_ast = conf.print_ast;
+        let code = std::fs::read_to_string(file).expect(&format!("File not found: '{}'", file));
-    interpreter.optimize_ast = !conf.no_optimizations;
+        let tokens = lex(&code);
+        let ast = parse(tokens);
 
-    if let Some(file) = &conf.file {
+        let prog = compile(&ast);
-        let code = match fs::read_to_string(file) {
+
-            Ok(code) => code,
+        // println!("{:?}", prog);
-            Err(_) => nice_panic!("Error: Could not read file '{}'", file),
+
-        };
+        let mut vm = Vm::new(prog);
-        // Lex, parse and run the program
+
-        interpreter.run_str(&code);
+        vm.run();
-    } else {
+
-        println!("Error: No file given\n");
+        // interpreter.run_text(&code, cfg.print_tokens, cfg.print_ast);
-        print_help();
+    }
+
+    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);
+        }
     }
 }
-
-fn print_help() {
-    println!("Usage nek-lang [FLAGS] [FILE]");
-    println!("FLAGS: ");
-    println!("-t, --token        Print the lexed tokens");
-    println!("-a, --ast          Print the abstract syntax tree");
-    println!("-n, --no-opt       Disable the AST optimizations");
-    println!("-h, --help         Show this help screen");
-    exit(0);
-}

src/parser.rs

@@ -1,376 +1,186 @@
-use thiserror::Error;
+use std::iter::Peekable;
 
 use crate::{
-    ast::{Ast, BlockScope, Expression, FunDecl, If, Loop, Statement, VarDecl},
+    ast::{Ast, BinOpType, Expr, Stmt, UnOpType},
-    stringstore::{Sid, StringStore},
+    token::{Keyword, Literal, Token},
-    token::Token,
-    util::{PutBackIter, PutBackableExt},
-    T,
 };
 
-/// Errors that can occur while parsing
-#[derive(Debug, Error)]
-pub enum ParseErr {
-    #[error("Unexpected Token \"{0:?}\", expected \"{1}\"")]
-    UnexpectedToken(Token, String),
-
-    #[error("Left hand side of declaration is not a variable")]
-    DeclarationOfNonVar,
-
-    #[error("Use of undefined variable \"{0}\"")]
-    UseOfUndeclaredVar(String),
-
-    #[error("Use of undefined function \"{0}\"")]
-    UseOfUndeclaredFun(String),
-
-    #[error("Redeclation of function \"{0}\"")]
-    RedeclarationFun(String),
-
-    #[error("Function not declared at top level \"{0}\"")]
-    FunctionOnNonTopLevel(String),
-}
-
-/// A result that can either be Ok, or a ParseErr
-type ResPE<T> = Result<T, ParseErr>;
-
-/// This macro can be used to quickly and easily assert if the next token is matching the expected
-/// token and return an appropriate error if not. Since this is intended to be used inside the 
-/// parser, the first argument should always be `self`.
-macro_rules! validate_next {
-    ($self:ident, $expected_tok:pat, $expected_str:expr) => {
-        match $self.next() {
-            $expected_tok => (),
-            tok => return Err(ParseErr::UnexpectedToken(tok, format!("{}", $expected_str))),
-        }
-    };
-}
-
-/// Parse the given tokens into an abstract syntax tree
-pub fn parse<T: Iterator<Item = Token>, A: IntoIterator<IntoIter = T>>(tokens: A) -> ResPE<Ast> {
-    let parser = Parser::new(tokens);
-    parser.parse()
-}
-
-/// A parser that takes in a Token Stream and can create a full abstract syntax tree from it.
 struct Parser<T: Iterator<Item = Token>> {
-    tokens: PutBackIter<T>,
+    tokens: Peekable<T>,
-    string_store: StringStore,
-    var_stack: Vec<Sid>,
-    fun_stack: Vec<Sid>,
-    nesting_level: usize,
 }
 
 impl<T: Iterator<Item = Token>> Parser<T> {
     /// Create a new parser to parse the given Token Stream
-    pub fn new<A: IntoIterator<IntoIter = T>>(tokens: A) -> Self {
+    fn new<A: IntoIterator<IntoIter = T>>(tokens: A) -> Self {
-        let tokens = tokens.into_iter().putbackable();
+        let tokens = tokens.into_iter().peekable();
-        let string_store = StringStore::new();
+        Self { tokens }
-        let var_stack = Vec::new();
-        let fun_stack = Vec::new();
-        Self {
-            tokens,
-            string_store,
-            var_stack,
-            fun_stack,
-            nesting_level: 0,
-        }
     }
 
-    /// Consume the parser and try to create the abstract syntax tree from the token stream
+    /// Get the next Token without removing it
-    pub fn parse(mut self) -> ResPE<Ast> {
+    fn peek(&mut self) -> &Token {
-        let main = self.parse_scoped_block()?;
+        self.tokens.peek().unwrap_or(&Token::EoF)
-        Ok(Ast {
-            main,
-            stringstore: self.string_store,
-        })
     }
 
-    /// Parse a series of statements together as a BlockScope. This will continuously parse 
+    /// Advance to next Token and return the removed Token
-    /// statements until encountering end-of-file or a block end '}' .
+    fn next(&mut self) -> Token {
-    fn parse_scoped_block(&mut self) -> ResPE<BlockScope> {
+        self.tokens.next().unwrap_or(Token::EoF)
-        self.parse_scoped_block_fp_offset(0)
     }
 
-    /// Same as parse_scoped_block, but an offset to the framepointer can be specified to allow
+    fn parse(&mut self) -> Ast {
-    /// for easily passing variables into scopes from the outside. This is used when parsing 
-    /// function calls
-    fn parse_scoped_block_fp_offset(&mut self, framepointer_offset: usize) -> ResPE<BlockScope> {
-        self.nesting_level += 1;
-        let framepointer = self.var_stack.len() - framepointer_offset;
         let mut prog = Vec::new();
 
         loop {
-            match self.peek() {
+            let stmt = match self.peek() {
-                // Just a semicolon is an empty statement. So just consume it
+                Token::Semicolon => {
-                T![;] => {
                     self.next();
+                    continue;
                 }
+                Token::EoF => break,
+                Token::RBrace => break,
 
-                // '}' end the current block and EoF ends everything, as the end of the tokenstream 
+                Token::Keyword(keyword) => match keyword {
-                // is reached
+                    Keyword::Let => self.parse_let_stmt(),
-                T![EoF] | T!['}'] => break,
+                    Keyword::While => self.parse_while(),
+                    Keyword::If => self.parse_if(),
+                    Keyword::For => self.parse_for(),
+                    Keyword::Else => panic!("Unexpected else keyword"),
+                },
 
-                // Create a new scoped block
+                Token::Dollar => {
-                T!['{'] => {
                     self.next();
-                    prog.push(Statement::Block(self.parse_scoped_block()?));
+                    Stmt::Print(self.parse_expr())
-
-                    validate_next!(self, T!['}'], "}");
                 }
+                Token::DoubleDollar => {
+                    self.next();
+                    Stmt::DbgPrint(self.parse_expr())
+                }
+                // By default try to parse an expression
+                _ => Stmt::Expr(self.parse_expr()),
+            };
 
-                // By default try to lex statements
+            prog.push(stmt);
-                _ => prog.push(self.parse_stmt()?),
-            }
         }
 
-        // Reset the stack to where it was before entering the scope
+        Ast { prog }
-        self.var_stack.truncate(framepointer);
-        self.nesting_level -= 1;
-
-        Ok(prog)
     }
 
-    /// Parse a single statement from the tokens
+    fn parse_for(&mut self) -> Stmt {
-    fn parse_stmt(&mut self) -> ResPE<Statement> {
+        if !matches!(self.next(), Token::Keyword(Keyword::For)) {
-        let stmt = match self.peek() {
+            panic!("Error parsing for: Expected for token");
-            // Break statement
+        }
-            T![break] => {
-                self.next();
 
-                // After the statement, there must be a semicolon
+        let init = match self.parse_let_stmt() {
-                validate_next!(self, T![;], ";");
+            Stmt::Let(name, rhs) => (name, rhs),
-
+            _ => unreachable!(),
-                Statement::Break
-            }
-
-            // Continue statement
-            T![continue] => {
-                self.next();
-
-                // After the statement, there must be a semicolon
-                validate_next!(self, T![;], ";");
-
-                Statement::Continue
-            }
-
-            // Loop statement
-            T![loop] => Statement::Loop(self.parse_loop()?),
-
-            // Print statement
-            T![print] => {
-                self.next();
-
-                let expr = self.parse_expr()?;
-
-                // After the statement, there must be a semicolon
-                validate_next!(self, T![;], ";");
-
-                Statement::Print(expr)
-            }
-
-            // Return statement
-            T![return] => {
-                self.next();
-                let stmt = Statement::Return(self.parse_expr()?);
-
-                // After a statement, there must be a semicolon
-                validate_next!(self, T![;], ";");
-
-                stmt
-            }
-
-            // If statement
-            T![if] => Statement::If(self.parse_if()?),
-
-            // Function definition statement
-            T![fun] => {
-
-                self.next();
-
-                // Expect an identifier as the function name
-                let fun_name = match self.next() {
-                    T![ident(fun_name)] => fun_name,
-                    tok => return Err(ParseErr::UnexpectedToken(tok, "<ident>".to_string())),
-                };
-                
-                // Only allow function definitions on the top level
-                if self.nesting_level > 1 {
-                    return Err(ParseErr::FunctionOnNonTopLevel(fun_name));
-                }
-
-                // Intern the function name
-                let fun_name = self.string_store.intern_or_lookup(&fun_name);
-
-                // Check if the function name already exists
-                if self.fun_stack.contains(&fun_name) {
-                    return Err(ParseErr::RedeclarationFun(
-                        self.string_store
-                            .lookup(fun_name)
-                            .cloned()
-                            .unwrap_or("<unknown>".to_string()),
-                    ));
-                }
-
-                // Put the function name on the fucntion stack for precalculating the stack 
-                // positions
-                let fun_stackpos = self.fun_stack.len();
-                self.fun_stack.push(fun_name);
-
-
-                let mut arg_names = Vec::new();
-
-                validate_next!(self, T!['('], "(");
-
-                // Parse the optional arguments inside the parentheses
-                while matches!(self.peek(), T![ident(_)]) {
-                    let var_name = match self.next() {
-                        T![ident(var_name)] => var_name,
-                        _ => unreachable!(),
-                    };
-
-                    // Intern argument names 
-                    let var_name = self.string_store.intern_or_lookup(&var_name);
-                    arg_names.push(var_name);
-
-                    // Push the variable onto the varstack
-                    self.var_stack.push(var_name);
-
-                    // If there are more args skip the comma so that the loop will read the argname
-                    if self.peek() == &T![,] {
-                        self.next();
-                    }
-                }
-
-                validate_next!(self, T![')'], ")");
-
-                validate_next!(self, T!['{'], "{");
-
-                // Create the scoped block with a stack offset. This will pop the args that are
-                // added to the stack while parsing args
-                let body = self.parse_scoped_block_fp_offset(arg_names.len())?;
-
-                validate_next!(self, T!['}'], "}");
-
-                Statement::FunDeclare(FunDecl {
-                    name: fun_name,
-                    fun_stackpos,
-                    argnames: arg_names,
-                    body: body.into(),
-                })
-            }
-
-            // Either a variable declaration statement or an expression statement
-            _ => {
-                // To decide if it is a declaration or an expression, a lookahead is needed 
-                let first = self.next();
-
-                let stmt = match (first, self.peek()) {
-                    // Identifier and "<-" is a declaration
-                    (T![ident(name)], T![<-]) => {
-                        self.next();
-
-                        let rhs = self.parse_expr()?;
-
-                        let sid = self.string_store.intern_or_lookup(&name);
-                        let sp = self.var_stack.len();
-                        self.var_stack.push(sid);
-
-                        Statement::Declaration(VarDecl {
-                            name: sid,
-                            var_stackpos: sp,
-                            rhs,
-                        })
-                    }
-                    // Anything else must be an expression
-                    (first, _) => {
-                        // Put the first token back in order for the parse_expr to see it 
-                        self.putback(first);
-                        Statement::Expr(self.parse_expr()?)
-                    }
-                };
-
-                // After a statement, there must be a semicolon
-                validate_next!(self, T![;], ";");
-
-                stmt
-            }
         };
-        Ok(stmt)
+
+        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)
     }
 
-    /// Parse an if statement from the tokens
+    fn parse_if(&mut self) -> Stmt {
-    fn parse_if(&mut self) -> ResPE<If> {
+        if !matches!(self.next(), Token::Keyword(Keyword::If)) {
-        validate_next!(self, T![if], "if");
+            panic!("Error parsing if: Expected if token");
+        }
 
-        let condition = self.parse_expr()?;
+        let condition = self.parse_expr();
 
-        validate_next!(self, T!['{'], "{");
+        if !matches!(self.next(), Token::LBrace) {
+            panic!("Error parsing if: Expected '{{' token");
+        }
 
-        let body_true = self.parse_scoped_block()?;
+        let body_if = self.parse();
 
-        validate_next!(self, T!['}'], "}");
+        if !matches!(self.next(), Token::RBrace) {
+            panic!("Error parsing if: Expected '}}' token");
+        }
 
-        let mut body_false = BlockScope::default();
+        let mut body_else = Ast { prog: Vec::new() };
 
-        // Optionally parse the else part
+        if matches!(self.peek(), Token::Keyword(Keyword::Else)) {
-        if self.peek() == &T![else] {
             self.next();
 
-            validate_next!(self, T!['{'], "{");
+            if !matches!(self.next(), Token::LBrace) {
+                panic!("Error parsing else: Expected '{{' token");
+            }
 
-            body_false = self.parse_scoped_block()?;
+            body_else = self.parse();
 
-            validate_next!(self, T!['}'], "}");
+            if !matches!(self.next(), Token::RBrace) {
-        }
+                panic!("Error parsing else: Expected '}}' token");
-
-        Ok(If {
-            condition,
-            body_true,
-            body_false,
-        })
-    }
-
-    /// Parse a loop statement from the tokens
-    fn parse_loop(&mut self) -> ResPE<Loop> {
-        validate_next!(self, T![loop], "loop");
-
-        let mut condition = None;
-        let mut advancement = None;
-
-        // Check if the optional condition is present
-        if !matches!(self.peek(), T!['{']) {
-            condition = Some(self.parse_expr()?);
-
-            // Check if the optional advancement is present
-            if matches!(self.peek(), T![;]) {
-                self.next();
-                advancement = Some(self.parse_expr()?);
             }
         }
 
-        validate_next!(self, T!['{'], "{");
+        Stmt::If(condition, body_if, body_else)
-
-        let body = self.parse_scoped_block()?;
-
-        validate_next!(self, T!['}'], "}");
-
-        Ok(Loop {
-            condition,
-            advancement,
-            body,
-        })
     }
 
-    /// Parse a single expression from the tokens
+    fn parse_while(&mut self) -> Stmt {
-    fn parse_expr(&mut self) -> ResPE<Expression> {
+        if !matches!(self.next(), Token::Keyword(Keyword::While)) {
-        let lhs = self.parse_primary()?;
+            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.
+    /// Parse binary expressions with a precedence equal to or higher than min_prec
-    /// This uses the precedence climbing methode for dealing with the operator precedences:
+    fn parse_expr_precedence(&mut self, mut lhs: Expr, min_prec: u8) -> Expr {
-    /// https://en.wikipedia.org/wiki/Operator-precedence_parser#Precedence_climbing_method
-    fn parse_expr_precedence(&mut self, mut lhs: Expression, min_prec: u8) -> ResPE<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) {
@@ -381,211 +191,117 @@ impl<T: Iterator<Item = Token>> Parser<T> {
             // valid
             let binop = self.next().try_to_binop().unwrap();
 
-            let mut rhs = self.parse_primary()?;
+            let mut rhs = self.parse_primary();
 
             while let Some(binop2) = &self.peek().try_to_binop() {
                 if !(binop2.precedence() > binop.precedence()) {
                     break;
                 }
 
-                rhs = self.parse_expr_precedence(rhs, binop.precedence() + 1)?;
+                rhs = self.parse_expr_precedence(rhs, binop.precedence() + 1);
             }
 
-            lhs = Expression::BinOp(binop, lhs.into(), rhs.into());
+            lhs = Expr::BinOp(binop, lhs.into(), rhs.into());
         }
 
-        Ok(lhs)
+        lhs
     }
 
-    /// Parse a primary expression. A primary can be a literal value, variable, function call,
+    /// Parse a primary expression (for now only number)
-    /// array indexing, parentheses grouping or a unary operation
+    fn parse_primary(&mut self) -> Expr {
-    fn parse_primary(&mut self) -> ResPE<Expression> {
+        match self.next() {
-        let primary = match self.next() {
+            Token::Literal(Literal::I64(val)) => Expr::I64(val),
-            // Literal i64
-            T![i64(val)] => Expression::I64(val),
 
-            // Literal String
+            Token::Literal(Literal::Str(text)) => Expr::Str(text.into()),
-            T![str(text)] => Expression::String(self.string_store.intern_or_lookup(&text)),
 
-            // Array literal. Square brackets containing the array size as expression
+            Token::Ident(name) => Expr::Ident(name),
-            T!['['] => {
-                let size = self.parse_expr()?;
 
-                validate_next!(self, T![']'], "]");
+            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();
 
-                Expression::ArrayLiteral(size.into())
+                // 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 ')'");
-            // Array sccess, aka indexing. An ident followed by square brackets containing the
-            // index as an expression
-            T![ident(name)] if self.peek() == &T!['['] => {
-                // Get the stack position of the array variable
-                let sid = self.string_store.intern_or_lookup(&name);
-                let stackpos = self.get_stackpos(sid)?;
-
-                self.next();
-
-                let index = self.parse_expr()?;
-
-                validate_next!(self, T![']'], "]");
-
-                Expression::ArrayAccess(sid, stackpos, index.into())
-            }
-
-            // Identifier followed by parenthesis is a function call
-            T![ident(name)] if self.peek() == &T!['('] => {
-                // Skip the opening parenthesis
-                self.next();
-
-                let sid = self.string_store.intern_or_lookup(&name);
-
-                let mut args = Vec::new();
-
-                // Parse the arguments as expressions
-                while !matches!(self.peek(), T![')']) {
-                    let arg = self.parse_expr()?;
-                    args.push(arg);
-
-                    // If there are more args skip the comma so that the loop will read the argname
-                    if self.peek() == &T![,] {
-                        self.next();
-                    }
                 }
 
-                validate_next!(self, T![')'], ")");
+                inner
-
-                // Find the function stack position
-                let fun_stackpos = self.get_fun_stackpos(sid)?;
-
-                Expression::FunCall(sid, fun_stackpos, args)
             }
 
-            // Just an identifier is a variable
+            Token::Sub => Expr::UnOp(UnOpType::Neg, self.parse_primary().into()),
-            T![ident(name)] => {
-                // Find the variable stack position
-                let sid = self.string_store.intern_or_lookup(&name);
-                let stackpos = self.get_stackpos(sid)?;
 
-                Expression::Var(sid, stackpos)
+            tok => panic!("Error parsing primary expr: Unexpected Token '{:?}'", tok),
-            }
+        }
-
-            // Parentheses grouping
-            T!['('] => {
-                // Contained inbetween the parentheses can be any other expression
-                let inner_expr = self.parse_expr()?;
-
-                // Verify that there is a closing parenthesis
-                validate_next!(self, T![')'], ")");
-
-                inner_expr
-            }
-
-            // Unary operations or invalid token
-            tok => match tok.try_to_unop() {
-                // If the token is a valid unary operation, parse it as such
-                Some(uot) => Expression::UnOp(uot, self.parse_primary()?.into()),
-                
-                // Otherwise it's an unexpected token
-                None => return Err(ParseErr::UnexpectedToken(tok, "primary".to_string())),
-            },
-        };
-
-        Ok(primary)
     }
 
-    /// Try to get the position of a variable on the variable stack. This is needed to precalculate 
+}
-    /// the stackpositions in order to save time when executing
-    fn get_stackpos(&self, varid: Sid) -> ResPE<usize> {
-        self.var_stack
-            .iter()
-            .rev()
-            .position(|it| *it == varid)
-            .map(|it| it)
-            .ok_or(ParseErr::UseOfUndeclaredVar(
-                self.string_store
-                    .lookup(varid)
-                    .map(String::from)
-                    .unwrap_or("<unknown>".to_string()),
-            ))
-    }
 
-    /// Try to get the position of a function on the function stack. This is needed to precalculate 
+pub fn parse<T: Iterator<Item = Token>, A: IntoIterator<IntoIter = T>>(tokens: A) -> Ast {
-    /// the stackpositions in order to save time when executing
+    let mut parser = Parser::new(tokens);
-    fn get_fun_stackpos(&self, varid: Sid) -> ResPE<usize> {
+    parser.parse()
-        self.fun_stack
+}
-            .iter()
-            .rev()
-            .position(|it| *it == varid)
-            .map(|it| self.fun_stack.len() - it - 1)
-            .ok_or(ParseErr::UseOfUndeclaredFun(
-                self.string_store
-                    .lookup(varid)
-                    .map(String::from)
-                    .unwrap_or("<unknown>".to_string()),
-            ))
-    }
 
-    /// Get the next Token without removing it. If there are no more tokens left, the EoF token is 
+impl BinOpType {
-    /// returned. This follows the same reasoning as in the Lexer
+    /// Get the precedence for a binary operator. Higher value means the OP is stronger binding.
-    fn peek(&mut self) -> &Token {
+    /// For example Multiplication is stronger than addition, so Mul has higher precedence than Add.
-        self.tokens.peek().unwrap_or(&T![EoF])
+    ///
-    }
+    /// 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.
-    /// Put a single token back into the token stream
+    /// See: https://en.cppreference.com/w/c/language/operator_precedence
-    fn putback(&mut self, tok: Token) {
+    fn precedence(&self) -> u8 {
-        self.tokens.putback(tok);
+        match self {
-    }
+            BinOpType::Assign => 0,
-
+            BinOpType::BOr => 1,
-    /// Advance to next Token and return the removed Token. If there are no more tokens left, the 
+            BinOpType::BXor => 2,
-    /// EoF token is returned. This follows the same reasoning as in the Lexer
+            BinOpType::BAnd => 3,
-    fn next(&mut self) -> Token {
+            BinOpType::Equ | BinOpType::Neq => 4,
-        self.tokens.next().unwrap_or(T![EoF])
+            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, BinOpType, Expr};
     use crate::{
-        ast::{BinOpType, Expression, Statement},
+        parser::{Ast, Stmt},
-        parser::parse,
+        token::{Literal, Token},
-        T,
     };
 
-    /// A very simple test to check if the parser correctly parses a simple expression
     #[test]
     fn test_parser() {
-        // Expression: 1 + 2 * 3 - 4
+        // Expression: 1 + 2 * 3 + 4
-        // With precedence: (1 + (2 * 3)) - 4
+        // With precedence: (1 + (2 * 3)) + 4
         let tokens = [
-            T![i64(1)],
+            Token::Literal(Literal::I64(1)),
-            T![+],
+            Token::Add,
-            T![i64(2)],
+            Token::Literal(Literal::I64(2)),
-            T![*],
+            Token::Mul,
-            T![i64(3)],
+            Token::Literal(Literal::I64(3)),
-            T![-],
+            Token::Sub,
-            T![i64(4)],
+            Token::Literal(Literal::I64(4)),
-            T![;],
         ];
 
-        let expected = Statement::Expr(Expression::BinOp(
+        let expected = Expr::BinOp(
             BinOpType::Sub,
-            Expression::BinOp(
+            Expr::BinOp(
                 BinOpType::Add,
-                Expression::I64(1).into(),
+                Expr::I64(1).into(),
-                Expression::BinOp(
+                Expr::BinOp(BinOpType::Mul, Expr::I64(2).into(), Expr::I64(3).into()).into(),
-                    BinOpType::Mul,
-                    Expression::I64(2).into(),
-                    Expression::I64(3).into(),
-                )
-                .into(),
             )
             .into(),
-            Expression::I64(4).into(),
+            Expr::I64(4).into(),
-        ));
+        );
 
-        let expected = vec![expected];
+        let expected = Ast {
+            prog: vec![Stmt::Expr(expected)],
+        };
 
-        let actual = parse(tokens).unwrap();
+        let actual = parse(tokens);
-        assert_eq!(expected, actual.main);
+        assert_eq!(expected, actual);
     }
 }

src/stringstore.rs

@@ -1,104 +0,0 @@
-use std::collections::HashMap;
-
-/// A StringID that identifies a String inside the stringstore. This is only valid for the 
-/// StringStore that created the ID. These StringIDs can be trivialy and cheaply copied
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
-pub struct Sid(usize);
-
-/// A Datastructure that stores strings, handing out StringIDs that can be used to retrieve the
-/// real strings at a later point. This is called interning.
-#[derive(Clone, Default)]
-pub struct StringStore {
-    /// The actual strings that are stored in the StringStore. The StringIDs match the index of the
-    /// string inside of this strings vector
-    strings: Vec<String>,
-    /// A Hashmap that allows to match already interned Strings to their StringID. This allows for
-    /// deduplication since the same string won't be stored twice
-    sids: HashMap<String, Sid>,
-}
-
-impl StringStore {
-
-    /// Create a new empty StringStore
-    pub fn new() -> Self {
-        Self { strings: Vec::new(), sids: HashMap::new() }
-    }
-
-    /// Put the given string into the StringStore and get a StringID in return. If the string is 
-    /// not yet stored, it will be after this.
-    /// 
-    /// Note: The generated StringIDs are only valid for the StringStore that created them. Using 
-    /// the IDs with another StringStore is undefined behavior. It might return wrong Strings or 
-    /// None.
-    pub fn intern_or_lookup(&mut self, text: &str) -> Sid {
-        self.sids.get(text).copied().unwrap_or_else(|| {
-            let sid = Sid(self.strings.len());
-            self.strings.push(text.to_string());
-            self.sids.insert(text.to_string(), sid);
-            sid
-        })
-    }
-
-    /// Lookup and retrieve a string by the StringID. If the String is not found, None is returned.
-    /// 
-    /// Note: The generated StringIDs are only valid for the StringStore that created them. Using 
-    /// the IDs with another StringStore is undefined behavior. It might return wrong Strings or 
-    /// None.
-    pub fn lookup(&self, sid: Sid) -> Option<&String> {
-        self.strings.get(sid.0)
-    }
-
-}
-
-#[cfg(test)]
-mod tests {
-    use super::StringStore;
-
-    #[test]
-    fn test_stringstore_intern_lookup() {
-        let mut ss = StringStore::new();
-        let s1 = "Hello";
-        let s2 = "World";
-
-        let id1 = ss.intern_or_lookup(s1);
-        assert_eq!(ss.lookup(id1).unwrap().as_str(), s1);
-
-        let id2 = ss.intern_or_lookup(s2);
-        assert_eq!(ss.lookup(id2).unwrap().as_str(), s2);
-        assert_eq!(ss.lookup(id1).unwrap().as_str(), s1);
-    }
-
-    #[test]
-    fn test_stringstore_no_duplicates() {
-        let mut ss = StringStore::new();
-        let s1 = "Hello";
-        let s2 = "World";
-
-        let id1_1 = ss.intern_or_lookup(s1);
-        assert_eq!(ss.lookup(id1_1).unwrap().as_str(), s1);
-
-        let id1_2 = ss.intern_or_lookup(s1);
-        assert_eq!(ss.lookup(id1_2).unwrap().as_str(), s1);
-
-        // Check that the string is the same
-        assert_eq!(id1_1, id1_2);
-
-        // Check that only one string is actually stored
-        assert_eq!(ss.strings.len(), 1);
-        assert_eq!(ss.sids.len(), 1);
-
-
-
-        let id2_1 = ss.intern_or_lookup(s2);
-        assert_eq!(ss.lookup(id2_1).unwrap().as_str(), s2);
-
-        let id2_2 = ss.intern_or_lookup(s2);
-        assert_eq!(ss.lookup(id2_2).unwrap().as_str(), s2);
-
-        // Check that the string is the same
-        assert_eq!(id2_1, id2_2);
-
-        assert_eq!(ss.strings.len(), 2);
-        assert_eq!(ss.sids.len(), 2);
-    }
-}

src/token.rs

@@ -1,379 +1,147 @@
-use crate::{
+use crate::ast::BinOpType;
-    ast::{BinOpType, UnOpType},
-    T,
-};
 
-/// Language keywords
-#[derive(Debug, PartialEq, Eq)]
-pub enum Keyword {
-    /// Loop keyword ("loop")
-    Loop,
-    /// Print keyword ("print")
-    Print,
-    /// If keyword ("if")
-    If,
-    /// Else keyword ("else")
-    Else,
-    /// Function declaration keyword ("fun")
-    Fun,
-    /// Return keyword ("return")
-    Return,
-    /// Break keyword ("break")
-    Break,
-    /// Continue keyword ("continue")
-    Continue,
-}
-
-/// Literal values
 #[derive(Debug, PartialEq, Eq)]
 pub enum Literal {
     /// Integer literal (64-bit)
     I64(i64),
-    /// String literal
+
-    String(String),
+    /// String literal ("Some string")
+    Str(String),
 }
 
-/// Combined tokens that consist of a combination of characters
 #[derive(Debug, PartialEq, Eq)]
-pub enum Combo {
+pub enum Keyword {
-    /// Equal Equal ("==")
+    /// Let identifier (let)
-    Equal2,
+    Let,
 
-    /// Exclamation mark Equal ("!=")
+    /// While (while)
-    ExclamationMarkEqual,
+    While,
 
-    /// Ampersand Ampersand ("&&")
+    /// For (for)
-    Ampersand2,
+    For,
 
-    /// Pipe Pipe ("||")
+    /// If (if)
-    Pipe2,
+    If,
 
-    /// LessThan LessThan ("<<")
+    /// Else (else)
-    LessThan2,
+    Else,
-
-    /// GreaterThan GreaterThan (">>")
-    GreaterThan2,
-
-    /// LessThan Equal ("<=")
-    LessThanEqual,
-
-    /// GreaterThan Equal (">=")
-    GreaterThanEqual,
-
-    /// LessThan Minus ("<-")
-    LessThanMinus,
 }
 
-/// Tokens are a group of one or more sourcecode characters that have a meaning together
 #[derive(Debug, PartialEq, Eq)]
 pub enum Token {
-    /// Literal value token
+    /// Literal values
     Literal(Literal),
 
-    /// Keyword token
+    /// Identifier (variable / function / ... name)
-    Keyword(Keyword),
-
-    /// Identifier token (names for variables, functions, ...)
     Ident(String),
 
-    /// Combined tokens consisting of multiple characters
+    /// Specific identifiers that have a special meaning as keywords
-    Combo(Combo),
+    Keyword(Keyword),
 
-    /// Comma (",")
+    /// Left parenthesis ('(')
-    Comma,
-
-    /// Equal Sign ("=")
-    Equal,
-
-    /// Semicolon (";")
-    Semicolon,
-
-    /// End of file (This is not generated by the lexer, but the parser uses this to find the 
-    /// end of the token stream)
-    EoF,
-
-    /// Left Bracket ("[")
-    LBracket,
-
-    /// Right Bracket ("]")
-    RBracket,
-
-    /// Left Parenthesis ("(")
     LParen,
 
-    /// Right Parenthesis (")"")
+    /// Right parentheses (')')
     RParen,
 
-    /// Left curly braces ("{")
+    /// Left brace ({)
-    LBraces,
+    LBrace,
 
-    /// Right curly braces ("}")
+    /// Right brace (})
-    RBraces,
+    RBrace,
 
-    /// Plus ("+")
+    /// Dollar sign ($)
-    Plus,
+    Dollar,
 
-    /// Minus ("-")
+    /// Double Dollar sign ($$)
-    Minus,
+    DoubleDollar,
 
-    /// Asterisk ("*")
+    /// Assignment (single equal) (=)
-    Asterisk,
+    Assign,
 
-    /// Slash ("/")
+    /// Plus (+)
-    Slash,
+    Add,
 
-    /// Percent ("%")
+    /// Minus (-)
-    Percent,
+    Sub,
 
-    /// Pipe ("|")
+    /// Asterisk (*)
-    Pipe,
+    Mul,
 
-    /// Tilde ("~")
+    /// Slash (/)
-    Tilde,
+    Div,
 
-    /// Logical not ("!")
+    /// Percent (%)
-    Exclamationmark,
+    Mod,
 
-    /// Left angle bracket ("<")
+    /// Pipe (|)
-    LessThan,
+    BOr,
 
-    /// Right angle bracket (">")
+    /// Ampersand (&)
-    GreaterThan,
+    BAnd,
 
-    /// Ampersand ("&")
+    /// Circumflex (^)
-    Ampersand,
+    BXor,
 
-    /// Circumflex ("^")
+    /// Shift Left (<<)
-    Circumflex,
+    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 {
-    /// If the Token can be used as a binary operation type, get the matching BinOpType. Otherwise
-    /// return None.
     pub fn try_to_binop(&self) -> Option<BinOpType> {
         Some(match self {
-            T![+] => BinOpType::Add,
+            Token::Add => BinOpType::Add,
-            T![-] => BinOpType::Sub,
+            Token::Sub => BinOpType::Sub,
 
-            T![*] => BinOpType::Mul,
+            Token::Mul => BinOpType::Mul,
-            T![/] => BinOpType::Div,
+            Token::Div => BinOpType::Div,
-            T![%] => BinOpType::Mod,
+            Token::Mod => BinOpType::Mod,
 
-            T![&] => BinOpType::BAnd,
+            Token::BAnd => BinOpType::BAnd,
-            T![|] => BinOpType::BOr,
+            Token::BOr => BinOpType::BOr,
-            T![^] => BinOpType::BXor,
+            Token::BXor => BinOpType::BXor,
 
-            T![&&] => BinOpType::LAnd,
+            Token::Shl => BinOpType::Shl,
-            T![||] => BinOpType::LOr,
+            Token::Shr => BinOpType::Shr,
 
-            T![<<] => BinOpType::Shl,
+            Token::Equ => BinOpType::Equ,
-            T![>>] => BinOpType::Shr,
+            Token::Neq => BinOpType::Neq,
 
-            T![==] => BinOpType::EquEqu,
+            Token::Gt => BinOpType::Gt,
-            T![!=] => BinOpType::NotEqu,
+            Token::Ge => BinOpType::Ge,
+            Token::Lt => BinOpType::Lt,
+            Token::Le => BinOpType::Le,
 
-            T![<] => BinOpType::Less,
+            Token::Assign => BinOpType::Assign,
-            T![<=] => BinOpType::LessEqu,
-
-            T![>] => BinOpType::Greater,
-            T![>=] => BinOpType::GreaterEqu,
-
-            T![=] => BinOpType::Assign,
-
-            _ => return None,
-        })
-    }
-
-    /// If the token can be used as a unary operation type, get the matching UnOpType. Otherwise 
-    /// return None
-    pub fn try_to_unop(&self) -> Option<UnOpType> {
-        Some(match self {
-            T![-] => UnOpType::Negate,
-            T![!] => UnOpType::LNot,
-            T![~] => UnOpType::BNot,
 
             _ => return None,
         })
     }
 }
-
-/// Macro to quickly create a token of the specified kind. As this is implemented as a macro, it 
-/// can be used anywhere including in patterns.
-/// 
-/// An implementation should exist for each token, so that there is no need to ever write out the
-/// long token definitions.
-#[macro_export]
-macro_rules! T {
-    // Keywords
-    [loop] => {
-        crate::token::Token::Keyword(crate::token::Keyword::Loop)
-    };
-
-    [print] => {
-        crate::token::Token::Keyword(crate::token::Keyword::Print)
-    };
-
-    [if] => {
-        crate::token::Token::Keyword(crate::token::Keyword::If)
-    };
-
-    [else] => {
-        crate::token::Token::Keyword(crate::token::Keyword::Else)
-    };
-
-    [fun] => {
-        crate::token::Token::Keyword(crate::token::Keyword::Fun)
-    };
-
-    [return] => {
-        crate::token::Token::Keyword(crate::token::Keyword::Return)
-    };
-
-    [break] => {
-        crate::token::Token::Keyword(crate::token::Keyword::Break)
-    };
-
-    [continue] => {
-        crate::token::Token::Keyword(crate::token::Keyword::Continue)
-    };
-
-    // Literals
-    [i64($($val:tt)*)] => {
-        crate::token::Token::Literal(crate::token::Literal::I64($($val)*))
-    };
-
-    [str($($val:tt)*)] => {
-        crate::token::Token::Literal(crate::token::Literal::String($($val)*))
-    };
-
-    // Ident
-    [ident($($val:tt)*)] => {
-        crate::token::Token::Ident($($val)*)
-    };
-
-    // Combo crate::token::Tokens
-    [==] => {
-        crate::token::Token::Combo(crate::token::Combo::Equal2)
-    };
-
-    [!=] => {
-        crate::token::Token::Combo(crate::token::Combo::ExclamationMarkEqual)
-    };
-
-    [&&] => {
-        crate::token::Token::Combo(crate::token::Combo::Ampersand2)
-    };
-
-    [||] => {
-        crate::token::Token::Combo(crate::token::Combo::Pipe2)
-    };
-
-    [<<] => {
-        crate::token::Token::Combo(crate::token::Combo::LessThan2)
-    };
-
-    [>>] => {
-        crate::token::Token::Combo(crate::token::Combo::GreaterThan2)
-    };
-
-    [<=] => {
-        crate::token::Token::Combo(crate::token::Combo::LessThanEqual)
-    };
-
-    [>=] => {
-        crate::token::Token::Combo(crate::token::Combo::GreaterThanEqual)
-    };
-
-    [<-] => {
-        crate::token::Token::Combo(crate::token::Combo::LessThanMinus)
-    };
-
-    // Normal Tokens
-    [,] => {
-        crate::token::Token::Comma
-    };
-
-    [=] => {
-        crate::token::Token::Equal
-    };
-
-    [;] => {
-        crate::token::Token::Semicolon
-    };
-
-    [EoF] => {
-        crate::token::Token::EoF
-    };
-
-    ['['] => {
-        crate::token::Token::LBracket
-    };
-
-    [']'] => {
-        crate::token::Token::RBracket
-    };
-
-    ['('] => {
-        crate::token::Token::LParen
-    };
-
-    [')'] => {
-        crate::token::Token::RParen
-    };
-
-    ['{'] => {
-        crate::token::Token::LBraces
-    };
-
-    ['}'] => {
-        crate::token::Token::RBraces
-    };
-
-    [+] => {
-        crate::token::Token::Plus
-    };
-
-    [-] => {
-        crate::token::Token::Minus
-    };
-
-    [*] => {
-        crate::token::Token::Asterisk
-    };
-
-    [/] => {
-        crate::token::Token::Slash
-    };
-
-    [%] => {
-        crate::token::Token::Percent
-    };
-
-    [|] => {
-        crate::token::Token::Pipe
-    };
-
-    [~] => {
-        crate::token::Token::Tilde
-    };
-
-    [!] => {
-        crate::token::Token::Exclamationmark
-    };
-
-    [<] => {
-        crate::token::Token::LessThan
-    };
-
-    [>] => {
-        crate::token::Token::GreaterThan
-    };
-
-    [&] => {
-        crate::token::Token::Ampersand
-    };
-
-    [^] => {
-        crate::token::Token::Circumflex
-    };
-}

src/util.rs

@@ -1,167 +0,0 @@
-/// Exit the program with error code 1 and format-print the given text on stderr. This pretty much
-/// works like panic, but doesn't show the additional information that panic adds. Those can be 
-/// interesting for debugging, but don't look that great when building a release executable for an
-/// end user.
-/// When running tests or running in debug mode, panic is used to ensure the tests working 
-/// correctly.
-#[macro_export]
-macro_rules! nice_panic {
-    ($fmt:expr) => {
-        {
-            if cfg!(test) || cfg!(debug_assertions) {
-                panic!($fmt);
-            } else {
-                eprintln!($fmt);
-                std::process::exit(1);
-            }
-        }
-    };
-    ($fmt:expr, $($arg:tt)*) => {
-        {
-            if cfg!(test) || cfg!(debug_assertions) {
-                panic!($fmt, $($arg)*);
-            } else {
-                eprintln!($fmt, $($arg)*);
-                std::process::exit(1);
-            }
-        }
-    };
-}
-
-/// The PutBackIter allows for items to be put back back and to be peeked. Putting an item back
-/// will cause it to be the next item returned by `next`. Peeking an item will get a reference to
-/// the next item in the iterator without removing it.
-///
-/// The whole PutBackIter behaves analogous to `std::iter::Peekable` with the addition of the
-/// `putback` function. This is slightly slower than `Peekable`, but allows for an unlimited number
-/// of putbacks and therefore an unlimited look-ahead range.
-pub struct PutBackIter<T: Iterator> {
-    iter: T,
-    putback_stack: Vec<T::Item>,
-}
-
-impl<T> PutBackIter<T>
-where
-    T: Iterator,
-{
-    /// Make the given iterator putbackable, wrapping it in the PutBackIter type. This effectively
-    /// adds the `peek` and `putback` functions.
-    pub fn new(iter: T) -> Self {
-        Self {
-            iter,
-            putback_stack: Vec::new(),
-        }
-    }
-
-    /// Put the given item back into the iterator. This causes the putbacked items to be returned by
-    /// next in last-in-first-out order (aka. stack order). Only after all previously putback items
-    /// have been returned, the actual underlying iterator is used to get items.
-    /// The number of items that can be put back is unlimited.
-    pub fn putback(&mut self, it: T::Item) {
-        self.putback_stack.push(it);
-    }
-
-    /// Peek the next item, getting a reference to it without removing it from the iterator. This
-    /// also includes items that were previsouly put back and not yet removed.
-    pub fn peek(&mut self) -> Option<&T::Item> {
-        if self.putback_stack.is_empty() {
-            let it = self.next()?;
-            self.putback(it);
-        }
-
-        self.putback_stack.last()
-    }
-}
-
-impl<T> Iterator for PutBackIter<T>
-where
-    T: Iterator,
-{
-    type Item = T::Item;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        match self.putback_stack.pop() {
-            Some(it) => Some(it),
-            None => self.iter.next(),
-        }
-    }
-}
-
-pub trait PutBackableExt {
-    /// Make the iterator putbackable, wrapping it in the PutBackIter type. This effectively
-    /// adds the `peek` and `putback` functions.
-    fn putbackable(self) -> PutBackIter<Self>
-    where
-        Self: Iterator + Sized,
-    {
-        PutBackIter::new(self)
-    }
-}
-
-impl<T: Iterator> PutBackableExt for T {}
-
-#[cfg(test)]
-mod tests {
-    use super::PutBackableExt;
-
-    #[test]
-    fn putback_iter_next() {
-        let mut iter = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10].into_iter();
-        let mut pb_iter = iter.clone().putbackable();
-
-        // Check if next works
-        for _ in 0..iter.len() {
-            assert_eq!(pb_iter.next(), iter.next());
-        }
-    }
-
-    #[test]
-    fn putback_iter_peek() {
-        let mut iter_orig = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10].into_iter();
-        let mut iter = iter_orig.clone();
-        let mut pb_iter = iter.clone().putbackable();
-
-        for _ in 0..iter.len() {
-            // Check if peek gives a preview of the actual next element
-            assert_eq!(pb_iter.peek(), iter.next().as_ref());
-            // Check if next still returns the next (just peeked) element and not the one after
-            assert_eq!(pb_iter.next(), iter_orig.next());
-        }
-    }
-
-    #[test]
-    fn putback_iter_putback() {
-        let mut iter_orig = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10].into_iter();
-        let mut iter = iter_orig.clone();
-        let mut pb_iter = iter.clone().putbackable();
-
-        // Get the first 5 items with next and check if they match
-        let it0 = pb_iter.next();
-        assert_eq!(it0, iter.next());
-        let it1 = pb_iter.next();
-        assert_eq!(it1, iter.next());
-        let it2 = pb_iter.next();
-        assert_eq!(it2, iter.next());
-        let it3 = pb_iter.next();
-        assert_eq!(it3, iter.next());
-        let it4 = pb_iter.next();
-        assert_eq!(it4, iter.next());
-
-        // Put one value back and check if `next` works as expected, returning the just put back
-        // item
-        pb_iter.putback(it0.unwrap());
-        assert_eq!(pb_iter.next(), it0);
-
-        // Put all values back
-        pb_iter.putback(it4.unwrap());
-        pb_iter.putback(it3.unwrap());
-        pb_iter.putback(it2.unwrap());
-        pb_iter.putback(it1.unwrap());
-        pb_iter.putback(it0.unwrap());
-
-        // After all values have been put back, the iter should match the original again
-        for _ in 0..iter.len() {
-            assert_eq!(pb_iter.next(), iter_orig.next());
-        }
-    }
-}

src/vm.rs

@@ -0,0 +1,187 @@
+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>,
+}
+
+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().map(|op| unsafe { std::mem::transmute::<u32, OP>(op) }) {
+            self.ip += 1;
+
+            match op {
+                OP::Push => {
+                    let val = self.read_i64();
+                    self.stack.push(Value::I64(val));
+                }
+                OP::Pop => {
+                    self.stack.pop();
+                }
+                OP::Load => {
+                    let addr = self.read_i64() as usize;
+
+                    if let Some(val) = self.heap.get(addr) {
+                        self.stack.push(val.clone());
+                    } else {
+                        panic!("Trying to load from uninitialized heap");
+                    }
+                }
+                OP::Store => {
+                    let val = self
+                        .stack
+                        .pop()
+                        .expect("Trying to pop value from stack for storing");
+                    let addr = self.read_i64() as usize;
+                    if self.heap.len() == addr {
+                        self.heap.push(val);
+                    } else {
+                        self.heap[addr] = val;
+                    }
+                }
+                OP::Print => {
+                    let val = self
+                        .stack
+                        .pop()
+                        .expect("Trying to pop value from stack for printing");
+                    print!("{}", val);
+                }
+                OP::DbgPrint => {
+                    let val = self
+                        .stack
+                        .pop()
+                        .expect("Trying to pop value from stack for printing");
+                    print!("{:?}", val);
+                }
+
+                OP::Add => {
+                    let vals = self.pop2_i64();
+                    self.stack.push(Value::I64(vals.0 + vals.1))
+                }
+                OP::Subtract => {
+                    let vals = self.pop2_i64();
+                    self.stack.push(Value::I64(vals.0 - vals.1))
+                }
+                OP::Multiply => {
+                    let vals = self.pop2_i64();
+                    self.stack.push(Value::I64(vals.0 * vals.1))
+                }
+                OP::Divide => {
+                    let vals = self.pop2_i64();
+                    self.stack.push(Value::I64(vals.0 / vals.1))
+                }
+                OP::Modulo => {
+                    let vals = self.pop2_i64();
+                    self.stack.push(Value::I64(vals.0 % vals.1))
+                }
+                OP::Eq => {
+                    let vals = self.pop2_i64();
+                    self.stack
+                        .push(Value::I64(if vals.0 == vals.1 { 1 } else { 0 }))
+                }
+                OP::Neq => {
+                    let vals = self.pop2_i64();
+                    self.stack
+                        .push(Value::I64(if vals.0 != vals.1 { 1 } else { 0 }))
+                }
+                OP::Gt => {
+                    let vals = self.pop2_i64();
+                    self.stack
+                        .push(Value::I64(if vals.0 > vals.1 { 1 } else { 0 }))
+                }
+                OP::Ge => {
+                    let vals = self.pop2_i64();
+                    self.stack
+                        .push(Value::I64(if vals.0 >= vals.1 { 1 } else { 0 }))
+                }
+                OP::Lt => {
+                    let vals = self.pop2_i64();
+                    self.stack
+                        .push(Value::I64(if vals.0 < vals.1 { 1 } else { 0 }))
+                }
+                OP::Le => {
+                    let vals = self.pop2_i64();
+                    self.stack
+                        .push(Value::I64(if vals.0 <= vals.1 { 1 } else { 0 }))
+                }
+                OP::BOr => {
+                    let vals = self.pop2_i64();
+                    self.stack.push(Value::I64(vals.0 | vals.1))
+                }
+                OP::BAnd => {
+                    let vals = self.pop2_i64();
+                    self.stack.push(Value::I64(vals.0 & vals.1))
+                }
+                OP::BXor => {
+                    let vals = self.pop2_i64();
+                    self.stack.push(Value::I64(vals.0 ^ vals.1))
+                }
+                OP::Shl => {
+                    let vals = self.pop2_i64();
+                    self.stack.push(Value::I64(vals.0 << vals.1))
+                }
+                OP::Shr => {
+                    let vals = self.pop2_i64();
+                    self.stack.push(Value::I64(vals.0 >> vals.1))
+                }
+                OP::Jump => {
+                    self.ip = self.read_i64() as usize;
+                }
+                OP::JumpTrue => {
+                    let jmp_target = self.read_i64() as usize;
+                    if !matches!(self.stack.pop(), Some(Value::I64(0))) {
+                        self.ip = jmp_target;
+                    }
+                }
+                OP::JumpFalse => {
+                    let jmp_target = self.read_i64() as usize;
+                    if matches!(self.stack.pop(), Some(Value::I64(0))) {
+                        self.ip = jmp_target;
+                    }
+                }
+            }
+        }
+    }
+
+    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 = *self.prog.get(self.ip).unwrap() as i64;
+        val |= (*self.prog.get(self.ip + 1).unwrap() as i64) << 32;
+
+        // let mut bytes = [0; 8];
+        // bytes.copy_from_slice(&self.prog[self.ip..self.ip+8]);
+        // val = i64::from_le_bytes(bytes);
+
+        // for i in 0 .. 8 {
+        //     if let Some(tmp) = self.prog.get(self.ip + i).copied() {
+        //         val |= ((tmp as i64) << i*8) as i64;
+        //     } else {
+        //         panic!("Expected Value as next OP")
+        //     }
+        // }
+
+        self.ip += 2;
+
+        val
+    }
+}