Implement vec based scopes

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

Cargo.toml

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

README.md

@@ -1,49 +1,13 @@
 # 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 
+Currently all variables are global and completely unscoped. That means no matter where a variable is declared, it remains over the whole remaining runtime of the progam.
-inner scoped. All variables defined in a scope that has ended do no longer exist and can't be 
+
-accessed.
+All variables are currently of type `i64` (64-bit signed integer)
 
 ### Declaration
 - Declare and initialize a new variable
-- Declaring a previously declared variable again will shadow the previous variable
+- Declaring a previously declared variable again is currently equivalent to an assignment
 - Declaration is needed before assignment or other usage
 - The variable name is on the left side of the `<-` operator
 - The assigned value is on the right side and can be any expression
@@ -61,62 +25,6 @@ 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 
@@ -146,9 +54,7 @@ Supported mathematical operations:
 - "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`.
+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`)
@@ -163,53 +69,37 @@ The equality and relational operations result in `1` if the condition is evaluat
 - 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`.
+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 
+- There is currently only the `loop` keyword that can act like a `while` with optional advancement (an expression that is executed after the loop body)
-  advancement (an expression that is executed after each loop)
+- The `loop` keyword is followed by the condition (an expression) without needing parentheses
-- 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;
+  i = i - 1;
 }
 
 // With advancement
 k <- 0;
-loop k < 10; k = k + 1 {
+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 (`{ }`)
+- The block *if-true* block is wrapped in braces (`{ }`)
 - *Optional:* If there is an `else` after the *if-block*, there must be a following *if-false*, aka. else block
-- 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;
@@ -222,88 +112,15 @@ if a == b {
 }
 ```
 
-### 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
+- 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";`
+- Print currently automatically adds a linebreak
 ```
 a <- 1;
-// Outputs `1` to the terminal
+print a; // Outputs `"1\n"` to the terminal
-print a;
-
-// Outputs a new-line to the terminal
-print "\n";
 ```
 
 ## Comments
@@ -323,8 +140,6 @@ Line comments can be initiated by using `//`
 - [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
-  - [x] Precalculate binary ops / unary ops that have only literal operands
 
 ## Language features
 
@@ -334,7 +149,7 @@ Line comments can be initiated by using `//`
     - [x] Subtraction `a - b`
     - [x] Multiplication `a * b`
     - [x] Division `a / b`
-    - [x] Modulo `a % b`
+    - [x] Modulo `a % b
     - [x] Negate `-a`
   - [x] Parentheses `(a + b) * c`
   - [x] Logical boolean operators
@@ -358,43 +173,23 @@ Line comments can be initiated by using `//`
 - [x] Variables
   - [x] Declaration
   - [x] Assignment
-  - [x] Local variables (for example inside loop, if, else, functions)
-  - [x] Scoped block for specific local vars `{ ... }`
 - [x] Statements with semicolon & Multiline programs
 - [x] Control flow
-  - [x] Loops
+  - [x] While loop `while X { ... }`
-    - [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] Creating array with size `X` as a variable `arr <- [X]`
-  - [x] Accessing arrays by index `arr[X]`
 - [x] IO Intrinsics
   - [x] Print
-- [x] Functions
-  - [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_LITERAL | STR_LITERAL
-ARRAY_ACCESS = IDENT "[" expr "]"
+expr_primary = LITERAL | IDENT | "(" expr ")" | "-" expr_primary | "~" 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)*
@@ -408,33 +203,10 @@ expr_lor = expr_land ("||" expr_land)*
 expr = expr_lor
 ```
 
-## Statements
+### Statements
 ```
-stmt_return = "return" expr ";"
-stmt_break = "break" ";"
-stmt_continue = "continue" ";"
-stmt_var_decl = IDENT "<-" expr ";"
-stmt_fun_decl = "fun" IDENT "(" (IDENT ",")* IDENT? ")" "{" stmt* "}"
-stmt_expr = expr ";"
-stmt_block = "{" stmt* "}"
-stmt_loop = "loop" (expr (";" expr)?)? "{" stmt* "}"
 stmt_if = "if" expr "{" stmt* "}" ("else" "{" stmt* "}")?
-stmt_print = "print" expr ";"
+stmt_loop = "loop" expr (";" expr)? "{" stmt* "}"
-stmt = stmt_return | stmt_break | stmt_continue | stmt_var_decl | stmt_fun_decl 
+stmt_expr = expr ";"
-     | stmt_expr | stmt_block | stmt_loop | stmt_if | stmt_print
+stmt = stmt_expr | stmt_loop
 ```
-
-# 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

@@ -7,7 +7,7 @@
 sum <- 0;
 i <- 0;
 loop i < 1_000; i = i + 1 {
-    if i % 3 == 0 || i % 5 == 0 {
+    if i % 3 == 0 | i % 5 == 0 {
         sum = sum + i;
     }
 }

examples/euler2.nek

@@ -10,12 +10,14 @@ sum <- 0;
 
 a <- 0;
 b <- 1;
+tmp <- 0;
+
 loop a < 4_000_000 {
     if a % 2 == 0 {
         sum = sum + a;
     }
 
-    tmp <- a;
+    tmp = a;
     a = b;
     b = b + tmp;
 }

examples/euler3.nek

@@ -18,10 +18,10 @@ loop number > 1 {
 
     div = div + 1;
     if div * div > number {
-        if number > 1 && number > result {
+        if number > 1 & number > result {
             result = number;
         }
-        break;
+        number = 0;
     }
 
 }

examples/euler4.nek

@@ -4,25 +4,30 @@
 // 
 // Correct Answer: 906609
 
-fun reverse(n) {
-    rev <- 0;
-    loop n {
-        rev = rev * 10 + n % 10;
-        n = n / 10;
-    }
-    return rev;
-}
 
 res <- 0;
 
-i <- 100;
+tmp <- 0;
-loop i < 1_000; i = i + 1 {
+num <- 0;
-    k <- i;
+num_rev <- 0;
-    loop k < 1_000; k = k + 1 {
-        num <- i * k;
-        num_rev <- reverse(num);
 
-        if num == num_rev && num > res {
+i <- 100;
+k <- 100;
+loop i < 1_000; i = i + 1 {
+    k = 100;
+    loop k < 1_000; k = k + 1 {
+        num_rev = 0;
+
+        num = i * k;
+
+        tmp = num;
+
+        loop tmp {
+            num_rev = num_rev*10 + tmp % 10;
+            tmp = tmp / 10;
+        }
+
+        if num == num_rev & num > res {
             res = num;
         }
     }

examples/euler4.py

@@ -4,19 +4,19 @@
 # 
 # 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 i in range(100, 999):
-    for k in range(i, 1_000):
+    for k in range(100, 999):
+
         num = i * k
-        num_rev = reverse(num)
+        tmp = num
+
+        num_rev = 0
+        while tmp != 0:
+            num_rev = num_rev*10 + tmp % 10
+            tmp = tmp // 10
         
         if num == num_rev and num > res:
             res = num

examples/euler5.nek

@@ -3,21 +3,26 @@
 // 
 // Correct Answer: 232_792_560
 
-fun gcd(x, y) {
+num <- 20;
-    loop y {
+should_continue <- 1;
-        tmp <- x;
+i <- 2;
-        x = y;
+
-        y = tmp % y;
+loop should_continue {
+    should_continue = 0;
+
+    i = 20;
+    loop i >= 2; i = i - 1 {
+        if num % i != 0 {
+            should_continue = 1;
+            
+            // break
+            i = 0;
+        }
     }
 
-    return x;
+    if should_continue == 1 {
+        num = num + 20;
+    }
 }
 
-result <- 1;
+print num;
-
-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

@@ -1,188 +1,126 @@
 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 ("==")
+    /// Compare Equal
     EquEqu,
 
-    /// Compare Not Equal ("!=")
+    /// Compare Not Equal
     NotEqu,
 
-    /// Compare Less than ("<")
+    /// Less than
     Less,
 
-    /// Compare Less than or Equal ("<=")
+    /// Less than or Equal
     LessEqu,
 
-    /// Compare Greater than (">")
+    /// Greater than
     Greater,
 
-    /// Compare Greater than or Equal (">=")
+    /// Greater than or Equal
     GreaterEqu,
 
-    /// Bitwise Or ("|")
+    /// Bitwise OR (inclusive or)
     BOr,
 
-    /// Bitwise And ("&")
+    /// Bitwise And
     BAnd,
 
-    /// Bitwise Xor / Exclusive Or ("^")
+    /// Bitwise Xor (exclusive or)
     BXor,
 
-    /// Logical And ("&&")
+    /// Logical And
     LAnd,
 
-    /// Logical Or ("||")
+    /// Logical Or
     LOr,
 
-    /// Bitwise Shift Left ("<<")
+    /// Shift Left
     Shl,
 
-    /// Bitwise Shift Right (">>")
+    /// Shift Right
     Shr,
 
-    /// Assign value to variable ("=")
+    /// Assign value to variable
     Assign,
+
+    /// Declare new variable with value
+    Declare,
 }
 
-/// Types for unary operations
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum UnOpType {
-    /// Unary Negation ("-")
+    /// Unary Negate
     Negate,
 
-    /// Bitwise Not / Bitflip ("~")
+    /// Bitwise Not
     BNot,
 
-    /// Logical Not ("!")
+    /// Logical Not
     LNot,
 }
 
-/// Ast Node for possible Expression variants
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum Expression {
     /// Integer literal (64-bit)
     I64(i64),
     /// String literal
-    String(Sid),
+    String(Rc<String>),
-
+    /// Variable
-    /// Array with size as an expression
+    Var(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>),
     /// Unary operation. Consists of type and operand
     UnOp(UnOpType, Box<Expression>),
 }
 
-/// 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>,
+    pub condition: Expression,
     /// This is executed after each loop to advance the condition variables
     pub advancement: Option<Expression>,
     /// The loop body that is executed each loop
-    pub body: BlockScope,
+    pub body: Ast,
 }
 
-/// 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,
+    pub body_true: Ast,
     /// The if body that is executed when the condition is false
-    pub body_false: BlockScope,
+    pub body_false: Ast,
 }
 
-/// 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
+#[derive(Debug, PartialEq, Eq, Clone, Default)]
-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
+    pub prog: Vec<Statement>,
-    /// 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 {
@@ -195,6 +133,7 @@ impl BinOpType {
 
     pub fn precedence(&self) -> u8 {
         match self {
+            BinOpType::Declare => 0,
             BinOpType::Assign => 1,
             BinOpType::LOr => 2,
             BinOpType::LAnd => 3,

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/interpreter.rs

@@ -1,253 +1,85 @@
-use std::{cell::RefCell, rc::Rc};
+use std::{fmt::Display, rc::Rc};
-use thiserror::Error;
 
 use crate::{
-    ast::{Ast, BinOpType, BlockScope, Expression, FunDecl, If, Statement, UnOpType},
+    ast::{Ast, BinOpType, Expression, If, Statement, 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
+    String(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
+    // Variable table stores the runtime values of variables
-    pub optimize_ast: bool,
+    vartable: Vec<(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 {
-            optimize_ast: true,
+            vartable: Vec::new(),
-            ..Self::default()
         }
     }
 
-    /// Get the captured output
+    fn get_var(&self, name: &str) -> Option<Value> {
-    pub fn output(&self) -> &[Value] {
+        self.vartable
-        &self.output
+            .iter()
+            .rev()
+            .find(|it| it.0 == name)
+            .map(|it| it.1.clone())
     }
 
-    /// Try to retrieve a variable value from the varstack. The idx is the index from the back of
+    fn get_var_mut(&mut self, name: &str) -> Option<&mut Value> {
-    /// the stack. So 0 is the last value, not the first
+        self.vartable
-    fn get_var(&self, idx: usize) -> Option<Value> {
+            .iter_mut()
-        self.vartable.get(self.vartable.len() - idx - 1).cloned()
+            .rev()
+            .find(|it| it.0 == name)
+            .map(|it| &mut it.1)
     }
 
-    /// Try to retrieve a mutable reference to a variable value from the varstack. The idx is the
+    pub fn run_str(&mut self, code: &str, print_tokens: bool, print_ast: bool) {
-    /// index from the back of the stack. So 0 is the last value, not the first
+        let tokens = lex(code).unwrap();
-    fn get_var_mut(&mut self, idx: usize) -> Option<&mut Value> {
+        if print_tokens {
-        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);
         }
 
-        // Parse the ast
+        let ast = parse(tokens);
-        let ast = match parse(tokens) {
+        if print_ast {
-            Ok(ast) => ast,
+            println!("{:#?}", ast);
-            Err(e) => nice_panic!("Parsing error: {}", e),
-        };
-
-        // Run the ast
-        match self.run_ast(ast) {
-            Ok(_) => (),
-            Err(e) => nice_panic!("Runtime error: {}", e),
-        }
-    }
-
-    /// Execute the given Ast within the interpreter
-    pub fn run_ast(&mut self, mut ast: Ast) -> Result<(), RuntimeError> {
-        // Optimize the ast
-        if self.optimize_ast {
-            ast = SimpleAstOptimizer::optimize(ast);
         }
 
-        if self.print_ast {
+        self.run(&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(&mut self, prog: &Ast) {
-    pub fn run_block(&mut self, prog: &BlockScope) -> Result<BlockExit, RuntimeError> {
+        let vartable_len = self.vartable.len();
-        self.run_block_fp_offset(prog, 0)
+        for stmt in &prog.prog {
-    }
-
-    /// 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),
-                Statement::Continue => return Ok(BlockExit::Continue),
-
-                Statement::Return(expr) => {
-                    let val = self.resolve_expr(expr)?;
-
-                    block_exit = BlockExit::Return(val);
-                    break 'blockloop;
-                }
-
                 Statement::Expr(expr) => {
-                    self.resolve_expr(expr)?;
+                    self.resolve_expr(expr);
                 }
 
-                Statement::Declaration(decl) => {
-                    let rhs = self.resolve_expr(&decl.rhs)?;
-                    self.vartable.push(rhs);
-                }
-
-                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
+                        if matches!(self.resolve_expr(&looop.condition), Value::I64(0)) {
-                        if let Some(condition) = &looop.condition {
+                            break;
-                            if matches!(self.resolve_expr(condition)?, Value::I64(0)) {
-                                break;
-                            }
                         }
 
-                        // Run the body
+                        self.run(&looop.body);
-                        let be = self.run_block(&looop.body)?;
-                        match be {
-                            // Propagate return
-                            be @ BlockExit::Return(_) => {
-                                block_exit = be;
-                                break 'blockloop;
-                            }
-                            BlockExit::Break => break,
-                            BlockExit::Continue | BlockExit::Normal => (),
-                        }
 
-                        // Run the advancement
                         if let Some(adv) = &looop.advancement {
-                            self.resolve_expr(&adv)?;
+                            self.resolve_expr(&adv);
                         }
                     }
                 }
 
                 Statement::Print(expr) => {
-                    let result = self.resolve_expr(expr)?;
+                    let result = self.resolve_expr(expr);
-
+                    print!("{}", result);
-                    if self.capture_output {
-                        self.output.push(result)
-                    } else {
-                        print!("{}", self.value_to_string(&result));
-                    }
                 }
 
                 Statement::If(If {
@@ -255,264 +87,73 @@ impl Interpreter {
                     body_true,
                     body_false,
                 }) => {
-                    // Run the right block depending on the conditions result being 0 or not 
+                    if matches!(self.resolve_expr(condition), Value::I64(0)) {
-                    let exit = if matches!(self.resolve_expr(condition)?, Value::I64(0)) {
+                        self.run(body_false);
-                        self.run_block(body_false)?
                     } else {
-                        self.run_block(body_true)?
+                        self.run(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);
+        self.vartable.truncate(vartable_len);
-
-        Ok(block_exit)
     }
 
-    /// Execute the given expression to retrieve the resulting value
+    fn resolve_expr(&mut self, expr: &Expression) -> Value {
-    fn resolve_expr(&mut self, expr: &Expression) -> Result<Value, RuntimeError> {
+        match expr {
-        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::BinOp(bo, lhs, rhs) => self.resolve_binop(bo, lhs, rhs),
-            Expression::UnOp(uo, operand) => self.resolve_unop(uo, operand)?,
+            Expression::UnOp(uo, operand) => self.resolve_unop(uo, operand),
-            Expression::Var(name, idx) => self.resolve_var(*name, *idx)?,
+            Expression::Var(name) => self.resolve_var(name),
-            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_var(&mut self, name: &str) -> Value {
-    fn resolve_unop(&mut self, uo: &UnOpType, operand: &Expression) -> Result<Value, RuntimeError> {
+        match self.get_var(name) {
-        // Recursively resolve the operands expression into an actual value
+            Some(val) => val.clone(),
-        let operand = self.resolve_expr(operand)?;
+            None => panic!("Variable '{}' used but not declared", name),
+        }
+    }
 
-        // Perform the correct operation, considering the operation and value type
+    fn resolve_unop(&mut self, uo: &UnOpType, operand: &Expression) -> Value {
-        Ok(match (operand, uo) {
+        let operand = self.resolve_expr(operand);
+
+        match (operand, uo) {
             (Value::I64(val), UnOpType::Negate) => Value::I64(-val),
             (Value::I64(val), UnOpType::BNot) => Value::I64(!val),
             (Value::I64(val), UnOpType::LNot) => Value::I64(if val == 0 { 1 } else { 0 }),
-            (val, _) => return Err(RuntimeError::UnOpInvalidType(val)),
+            _ => panic!("Value type is not compatible with unary operation"),
-        })
+        }
     }
 
-    /// Execute a binary operation and get the resulting value
+    fn resolve_binop(&mut self, bo: &BinOpType, lhs: &Expression, rhs: &Expression) -> Value {
-    fn resolve_binop(
+        let rhs = self.resolve_expr(rhs);
-        &mut self,
-        bo: &BinOpType,
-        lhs: &Expression,
-        rhs: &Expression,
-    ) -> Result<Value, RuntimeError> {
-        let rhs = self.resolve_expr(rhs)?;
 
-        // Handle assignments separate from the other binary operations
         match (&bo, &lhs) {
-            // Normal variable assignment
+            (BinOpType::Declare, Expression::Var(name)) => {
-            (BinOpType::Assign, Expression::Var(name, idx)) => {
+                self.vartable.push((name.clone(), rhs.clone()));
-                // Get the variable mutably and assign the right hand side value
+                return rhs;
-                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()),
-                        ))
-                    }
-                }
-
-                return Ok(rhs);
             }
-            // Array index assignment
+            (BinOpType::Assign, Expression::Var(name)) => {
-            (BinOpType::Assign, Expression::ArrayAccess(name, idx, arr_idx)) => {
+                match self.get_var_mut(name) {
-                // Calculate the array index
+                    Some(val) => *val = rhs.clone(),
-                let arr_idx = match self.resolve_expr(arr_idx)? {
+                    None => panic!("Runtime Error: Trying to assign value to undeclared variable"),
-                    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 rhs;
-                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
 
-        // 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),
@@ -527,27 +168,18 @@ impl Interpreter {
                 BinOpType::Greater => Value::I64(if lhs > rhs { 1 } else { 0 }),
                 BinOpType::GreaterEqu => Value::I64(if lhs >= rhs { 1 } else { 0 }),
 
-                BinOpType::Assign => unreachable!(),
+                BinOpType::Declare | 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
+impl Display for Value {
-    /// retrive the text values of Strings
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-    fn value_to_string(&self, val: &Value) -> String {
+        match self {
-        match val {
+            Value::I64(val) => write!(f, "{}", val),
-            Value::I64(val) => format!("{}", val),
+            Value::String(text) => write!(f, "{}", text),
-            Value::Array(val) => format!("{:?}", val.borrow()),
-            Value::String(text) => format!(
-                "{}",
-                self.stringstore
-                    .lookup(*text)
-                    .unwrap_or(&"<invalid string>".to_string())
-            ),
-            Value::Void => format!("void"),
         }
     }
 }
@@ -557,8 +189,6 @@ mod test {
     use super::{Interpreter, Value};
     use crate::ast::{BinOpType, Expression};
 
-    /// 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
@@ -582,7 +212,7 @@ mod test {
         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

@@ -1,9 +1,8 @@
+use crate::token::Token;
+use anyhow::Result;
 use std::{iter::Peekable, str::Chars};
 use thiserror::Error;
 
-use crate::{token::Token, T};
-
-/// Errors that can occur while lexing a given string
 #[derive(Debug, Error)]
 pub enum LexErr {
     #[error("Failed to parse '{0}' as i64")]
@@ -21,111 +20,116 @@ pub enum LexErr {
 
 /// Lex the provided code into a Token Buffer
 pub fn lex(code: &str) -> Result<Vec<Token>, LexErr> {
-    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 
+    /// The sourcecode text as an iterator over the chars
-    /// 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
+    fn lex(&mut self) -> Result<Vec<Token>, LexErr> {
-    fn lex(mut self) -> Result<Vec<Token>, LexErr> {
+        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
-            // can be used to directly match 2-char tokens
-            match (self.current_char, self.peek()) {
                 // Stop lexing at EOF
-                ('\0', _) => break,
+                '\0' => break,
 
-                // Skip / ignore whitespace
+                // Skip whitespace
-                (' ' | '\t' | '\n' | '\r', _) => (),
+                ' ' | '\t' | '\n' | '\r' => (),
 
                 // Line comment. Consume every char until linefeed (next line)
-                ('/', '/') => while !matches!(self.next(), '\n' | '\0') {},
+                '/' if matches!(self.peek(), '/') => while !matches!(self.next(), '\n' | '\0') {},
 
                 // Double character tokens
-                ('>', '>') => self.push_tok_consume(T![>>]),
+                '>' if matches!(self.peek(), '>') => {
-                ('<', '<') => self.push_tok_consume(T![<<]),
+                    self.next();
-                ('=', '=') => self.push_tok_consume(T![==]),
+                    tokens.push(Token::Shr);
-                ('!', '=') => self.push_tok_consume(T![!=]),
+                }
-                ('<', '=') => self.push_tok_consume(T![<=]),
+                '<' if matches!(self.peek(), '<') => {
-                ('>', '=') => self.push_tok_consume(T![>=]),
+                    self.next();
-                ('<', '-') => self.push_tok_consume(T![<-]),
+                    tokens.push(Token::Shl);
-                ('&', '&') => self.push_tok_consume(T![&&]),
+                }
-                ('|', '|') => self.push_tok_consume(T![||]),
+                '=' if matches!(self.peek(), '=') => {
+                    self.next();
+                    tokens.push(Token::EquEqu);
+                }
+                '!' if matches!(self.peek(), '=') => {
+                    self.next();
+                    tokens.push(Token::NotEqu);
+                }
+                '<' if matches!(self.peek(), '=') => {
+                    self.next();
+                    tokens.push(Token::LAngleEqu);
+                }
+                '>' if matches!(self.peek(), '=') => {
+                    self.next();
+                    tokens.push(Token::RAngleEqu);
+                }
+                '<' if matches!(self.peek(), '-') => {
+                    self.next();
+                    tokens.push(Token::LArrow);
+                }
+                '&' if matches!(self.peek(), '&') => {
+                    self.next();
+                    tokens.push(Token::LAnd);
+                }
+                '|' if matches!(self.peek(), '|') => {
+                    self.next();
+                    tokens.push(Token::LOr);
+                }
 
                 // Single character tokens
-                (',', _) => self.push_tok(T![,]),
+                ';' => tokens.push(Token::Semicolon),
-                (';', _) => self.push_tok(T![;]),
+                '+' => tokens.push(Token::Add),
-                ('+', _) => self.push_tok(T![+]),
+                '-' => tokens.push(Token::Sub),
-                ('-', _) => self.push_tok(T![-]),
+                '*' => tokens.push(Token::Mul),
-                ('*', _) => self.push_tok(T![*]),
+                '/' => tokens.push(Token::Div),
-                ('/', _) => self.push_tok(T![/]),
+                '%' => tokens.push(Token::Mod),
-                ('%', _) => self.push_tok(T![%]),
+                '|' => tokens.push(Token::BOr),
-                ('|', _) => self.push_tok(T![|]),
+                '&' => tokens.push(Token::BAnd),
-                ('&', _) => self.push_tok(T![&]),
+                '^' => tokens.push(Token::BXor),
-                ('^', _) => self.push_tok(T![^]),
+                '(' => tokens.push(Token::LParen),
-                ('(', _) => self.push_tok(T!['(']),
+                ')' => tokens.push(Token::RParen),
-                (')', _) => self.push_tok(T![')']),
+                '~' => tokens.push(Token::Tilde),
-                ('~', _) => self.push_tok(T![~]),
+                '<' => tokens.push(Token::LAngle),
-                ('<', _) => self.push_tok(T![<]),
+                '>' => tokens.push(Token::RAngle),
-                ('>', _) => self.push_tok(T![>]),
+                '=' => tokens.push(Token::Equ),
-                ('=', _) => self.push_tok(T![=]),
+                '{' => tokens.push(Token::LBraces),
-                ('{', _) => self.push_tok(T!['{']),
+                '}' => tokens.push(Token::RBraces),
-                ('}', _) => self.push_tok(T!['}']),
+                '!' => tokens.push(Token::LNot),
-                ('!', _) => self.push_tok(T![!]),
-                ('[', _) => self.push_tok(T!['[']),
-                (']', _) => self.push_tok(T![']']),
 
                 // Special tokens with variable length
 
                 // Lex multiple characters together as numbers
-                ('0'..='9', _) => self.lex_number()?,
+                ch @ '0'..='9' => tokens.push(self.lex_number(ch)?),
 
                 // Lex multiple characters together as a string
-                ('"', _) => self.lex_str()?,
+                '"' => tokens.push(self.lex_str()?),
 
-                // Lex multiple characters together as identifier or keyword
+                // Lex multiple characters together as identifier
-                ('a'..='z' | 'A'..='Z' | '_', _) => self.lex_identifier()?,
+                ch @ ('a'..='z' | 'A'..='Z' | '_') => tokens.push(self.lex_identifier(ch)?),
 
-                // Any character that was not handled otherwise is invalid
+                ch => Err(LexErr::UnexpectedChar(ch))?,
-                (ch, _) => Err(LexErr::UnexpectedChar(ch))?,
             }
         }
 
-        Ok(self.tokens)
+        Ok(tokens)
     }
 
-    /// Lex multiple characters as a number until encountering a non numeric digit. The
+    /// Lex multiple characters as a number until encountering a non numeric digit. This includes
-    /// successfully lexed i64 literal token is appended to the stored tokens.
+    /// the first character
-    fn lex_number(&mut self) -> Result<(), LexErr> {
+    fn lex_number(&mut self, first_char: char) -> Result<Token, LexErr> {
         // String representation of the integer value
-        let mut sval = String::from(self.current_char);
+        let mut sval = String::from(first_char);
 
         // Do as long as a next char exists and it is a numeric char
         loop {
@@ -143,40 +147,31 @@ impl<'a> Lexer<'a> {
             }
         }
 
-        // Try to convert the string representation of the value to i64. The error is mapped to
+        // Try to convert the string representation of the value to i64
-        // the appropriate LexErr
         let i64val = sval.parse().map_err(|_| LexErr::NumericParse(sval))?;
-
+        Ok(Token::I64(i64val))
-        self.push_tok(T![i64(i64val)]);
-
-        Ok(())
     }
 
-    /// Lex characters as a string until encountering an unescaped closing doublequoute char '"'.
+    /// Lex characters as a string until encountering an unescaped closing doublequoute char '"'
-    /// The successfully lexed string literal token is appended to the stored tokens.
+    fn lex_str(&mut self) -> Result<Token, LexErr> {
-    fn lex_str(&mut self) -> Result<(), LexErr> {
+        // Opening " was consumed in match
-        // The opening " was consumed in match, so a fresh string can be used
+
         let mut text = String::new();
 
         // Read all chars until encountering the closing "
         loop {
             match self.peek() {
-                // An unescaped doubleqoute ends the current string
                 '"' => break,
-
                 // If the end of file is reached while still waiting for '"', error out
                 '\0' => Err(LexErr::MissingClosingString)?,
-
                 _ => match self.next() {
-                    // Backslash indicates an escaped character, so consume one more char and
+                    // Backshlash indicates an escaped character
-                    // treat it as the escaped char
                     '\\' => match self.next() {
                         'n' => text.push('\n'),
                         'r' => text.push('\r'),
                         't' => text.push('\t'),
                         '\\' => text.push('\\'),
                         '"' => text.push('"'),
-                        // If the escaped char is not handled, it is unsupported and an error
                         ch => Err(LexErr::InvalidStrEscape(ch))?,
                     },
                     // All other characters are simply appended to the string
@@ -188,15 +183,12 @@ impl<'a> Lexer<'a> {
         // Consume closing "
         self.next();
 
-        self.push_tok(T![str(text)]);
+        Ok(Token::String(text))
-
-        Ok(())
     }
 
-    /// Lex characters from the text as an identifier. The successfully lexed ident or keyword
+    /// Lex characters from the text as an identifier. This includes the first character passed in
-    /// token is appended to the stored tokens.
+    fn lex_identifier(&mut self, first_char: char) -> Result<Token, LexErr> {
-    fn lex_identifier(&mut self) -> Result<(), LexErr> {
+        let mut ident = String::from(first_char);
-        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 {
@@ -212,46 +204,24 @@ impl<'a> Lexer<'a> {
 
         // Check for pre-defined keywords
         let token = match ident.as_str() {
-            "loop" => T![loop],
+            "loop" => Token::Loop,
-            "print" => T![print],
+            "print" => Token::Print,
-            "if" => T![if],
+            "if" => Token::If,
-            "else" => T![else],
+            "else" => Token::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)],
+            _ => Token::Ident(ident),
         };
 
-        self.push_tok(token);
+        Ok(token)
-
-        Ok(())
     }
 
-    /// Push the given token into the stored tokens
+    /// Advance to next character and return the removed char
-    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,
+    /// Get the next character without removing it
-    /// `'\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')
     }
@@ -259,52 +229,31 @@ impl<'a> Lexer<'a> {
 
 #[cfg(test)]
 mod tests {
-    use crate::{lexer::lex, T};
+    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::I64(33),
-            T![+],
+            Token::Add,
-            T![i64(1)],
+            Token::I64(5),
-            T![-],
+            Token::Mul,
-            T![i64(567_000)],
+            Token::I64(2),
-            T![*],
+            Token::Add,
-            T![/],
+            Token::I64(4456467),
-            T![%],
+            Token::Mul,
-            T![|],
+            Token::I64(2334),
-            T![~],
+            Token::Add,
-            T![!],
+            Token::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();

src/lib.rs

@@ -1,68 +1,5 @@
+pub mod lexer;
+pub mod token;
+pub mod parser;
 pub mod ast;
 pub mod interpreter;
-pub mod lexer;
-pub mod parser;
-pub mod token;
-pub mod stringstore;
-pub mod astoptimizer;
-pub mod util;
-
-/// 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

@@ -1,14 +1,16 @@
-use std::{env::args, fs, process::exit};
+use std::{
+    env::args,
+    fs,
+    io::{stdin, stdout, Write},
+};
 
-use nek_lang::{interpreter::Interpreter, nice_panic};
+use nek_lang::interpreter::Interpreter;
 
-/// 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>,
 }
 
@@ -20,40 +22,34 @@ fn main() {
         match arg.as_str() {
             "--token" | "-t" => conf.print_tokens = true,
             "--ast" | "-a" => conf.print_ast = true,
-            "--no-opt" | "-n" => conf.no_optimizations = true,
+            "--interactive" | "-i" => conf.interactive = true,
-            "--help" | "-h" => print_help(),
+            file if conf.file.is_none() => conf.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;
-    interpreter.print_ast = conf.print_ast;
-    interpreter.optimize_ast = !conf.no_optimizations;
-
     if let Some(file) = &conf.file {
-        let code = match fs::read_to_string(file) {
+        let code = fs::read_to_string(file).expect(&format!("File not found: '{}'", file));
-            Ok(code) => code,
+        interpreter.run_str(&code, conf.print_tokens, conf.print_ast);
-            Err(_) => nice_panic!("Error: Could not read file '{}'", file),
+    }
-        };
+
-        // Lex, parse and run the program
+    if conf.interactive || conf.file.is_none() {
-        interpreter.run_str(&code);
+        let mut code = String::new();
-    } else {
+
-        println!("Error: No file given\n");
+        loop {
-        print_help();
+            print!(">> ");
+            stdout().flush().unwrap();
+
+            code.clear();
+            stdin().read_line(&mut code).unwrap();
+
+            if code.trim() == "exit" {
+                break;
+            }
+
+            interpreter.run_str(&code, conf.print_tokens, conf.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 +1,168 @@
-use thiserror::Error;
+use std::iter::Peekable;
 
-use crate::{
+use crate::ast::*;
-    ast::{Ast, BlockScope, Expression, FunDecl, If, Loop, Statement, VarDecl},
+use crate::token::Token;
-    stringstore::{Sid, StringStore},
-    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> {
+pub fn parse<T: Iterator<Item = Token>, A: IntoIterator<IntoIter = T>>(tokens: A) -> Ast {
-    let parser = Parser::new(tokens);
+    let mut 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
+    /// Parse tokens into an abstract syntax tree. This will continuously parse statements until
-    pub fn parse(mut self) -> ResPE<Ast> {
+    /// encountering end-of-file or a block end '}' .
-        let main = self.parse_scoped_block()?;
+    fn parse(&mut self) -> Ast {
-        Ok(Ast {
-            main,
-            stringstore: self.string_store,
-        })
-    }
-
-    /// Parse a series of statements together as a BlockScope. This will continuously parse 
-    /// statements until encountering end-of-file or a block end '}' .
-    fn parse_scoped_block(&mut self) -> ResPE<BlockScope> {
-        self.parse_scoped_block_fp_offset(0)
-    }
-
-    /// Same as parse_scoped_block, but an offset to the framepointer can be specified to allow
-    /// 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() {
-                // Just a semicolon is an empty statement. So just consume it
+                Token::Semicolon => {
-                T![;] => {
                     self.next();
                 }
+                Token::EoF | Token::RBraces => break,
 
-                // '}' end the current block and EoF ends everything, as the end of the tokenstream 
+                // By default try to lex a statement
-                // is reached
+                _ => prog.push(self.parse_stmt()),
-                T![EoF] | T!['}'] => break,
-
-                // Create a new scoped block
-                T!['{'] => {
-                    self.next();
-                    prog.push(Statement::Block(self.parse_scoped_block()?));
-
-                    validate_next!(self, T!['}'], "}");
-                }
-
-                // By default try to lex statements
-                _ => 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
+    /// Parse a single statement from the tokens.
-    fn parse_stmt(&mut self) -> ResPE<Statement> {
+    fn parse_stmt(&mut self) -> Statement {
-        let stmt = match self.peek() {
+        match self.peek() {
-            // Break statement
+            Token::Loop => Statement::Loop(self.parse_loop()),
-            T![break] => {
+
+            Token::Print => {
                 self.next();
 
-                // After the statement, there must be a semicolon
+                let expr = self.parse_expr();
-                validate_next!(self, T![;], ";");
 
-                Statement::Break
+                // After a statement, there must be a semicolon
-            }
+                if !matches!(self.next(), Token::Semicolon) {
-
+                    panic!("Expected semicolon after statement");
-            // 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
+            Token::If => Statement::If(self.parse_if()),
-            T![return] => {
-                self.next();
-                let stmt = Statement::Return(self.parse_expr()?);
 
-                // After a statement, there must be a semicolon
+            // If it is not a loop, try to lex as an expression
-                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 stmt = Statement::Expr(self.parse_expr());
-                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![;], ";");
+                if !matches!(self.next(), Token::Semicolon) {
+                    panic!("Expected semicolon after statement");
+                }
 
                 stmt
             }
-        };
+        }
-        Ok(stmt)
     }
 
     /// Parse an if statement from the tokens
-    fn parse_if(&mut self) -> ResPE<If> {
+    fn parse_if(&mut self) -> If {
-        validate_next!(self, T![if], "if");
+        if !matches!(self.next(), Token::If) {
-
+            panic!("Error lexing if: Expected if token");
-        let condition = self.parse_expr()?;
-
-        validate_next!(self, T!['{'], "{");
-
-        let body_true = self.parse_scoped_block()?;
-
-        validate_next!(self, T!['}'], "}");
-
-        let mut body_false = BlockScope::default();
-
-        // Optionally parse the else part
-        if self.peek() == &T![else] {
-            self.next();
-
-            validate_next!(self, T!['{'], "{");
-
-            body_false = self.parse_scoped_block()?;
-
-            validate_next!(self, T!['}'], "}");
         }
 
-        Ok(If {
+        let condition = self.parse_expr();
-            condition,
-            body_true,
-            body_false,
-        })
-    }
 
-    /// Parse a loop statement from the tokens
+        if !matches!(self.next(), Token::LBraces) {
-    fn parse_loop(&mut self) -> ResPE<Loop> {
+            panic!("Error lexing if: Expected '{{'")
-        validate_next!(self, T![loop], "loop");
+        }
 
-        let mut condition = None;
+        let body_true = self.parse();
-        let mut advancement = None;
 
-        // Check if the optional condition is present
+        if !matches!(self.next(), Token::RBraces) {
-        if !matches!(self.peek(), T!['{']) {
+            panic!("Error lexing if: Expected '}}'")
-            condition = Some(self.parse_expr()?);
+        }
 
-            // Check if the optional advancement is present
+        let mut body_false = Ast::default();
-            if matches!(self.peek(), T![;]) {
+
-                self.next();
+        if matches!(self.peek(), Token::Else) {
-                advancement = Some(self.parse_expr()?);
+            self.next();
+
+            if !matches!(self.next(), Token::LBraces) {
+                panic!("Error lexing if: Expected '{{'")
+            }
+
+            body_false = self.parse();
+
+            if !matches!(self.next(), Token::RBraces) {
+                panic!("Error lexing if: Expected '}}'")
             }
         }
 
-        validate_next!(self, T!['{'], "{");
+        If {
+            condition,
+            body_true,
+            body_false,
+        }
+    }
 
-        let body = self.parse_scoped_block()?;
+    /// Parse a loop statement from the tokens
+    fn parse_loop(&mut self) -> Loop {
+        if !matches!(self.next(), Token::Loop) {
+            panic!("Error lexing loop: Expected loop token");
+        }
 
-        validate_next!(self, T!['}'], "}");
+        let condition = self.parse_expr();
+        let mut advancement = None;
 
-        Ok(Loop {
+        let body;
+
+        match self.next() {
+            Token::LBraces => {
+                body = self.parse();
+            }
+
+            Token::Semicolon => {
+                advancement = Some(self.parse_expr());
+
+                if !matches!(self.next(), Token::LBraces) {
+                    panic!("Error lexing loop: Expected '{{'")
+                }
+
+                body = self.parse();
+            }
+
+            _ => panic!("Error lexing loop: Expected ';' or '{{'"),
+        }
+
+        if !matches!(self.next(), Token::RBraces) {
+            panic!("Error lexing loop: Expected '}}'")
+        }
+
+        Loop {
             condition,
             advancement,
             body,
-        })
+        }
     }
 
     /// Parse a single expression from the tokens
-    fn parse_expr(&mut self) -> ResPE<Expression> {
+    fn parse_expr(&mut self) -> Expression {
-        let lhs = self.parse_primary()?;
+        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: Expression, min_prec: u8) -> Expression {
-    /// 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) {
@@ -381,190 +173,99 @@ 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());
         }
 
-        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) -> Expression {
-    fn parse_primary(&mut self) -> ResPE<Expression> {
+        match self.next() {
-        let primary = match self.next() {
             // Literal i64
-            T![i64(val)] => Expression::I64(val),
+            Token::I64(val) => Expression::I64(val),
 
             // Literal String
-            T![str(text)] => Expression::String(self.string_store.intern_or_lookup(&text)),
+            Token::String(text) => Expression::String(text.into()),
 
-            // Array literal. Square brackets containing the array size as expression
+            Token::Ident(name) => Expression::Var(name),
-            T!['['] => {
-                let size = self.parse_expr()?;
-
-                validate_next!(self, T![']'], "]");
-
-                Expression::ArrayLiteral(size.into())
-            }
-
-            // 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![')'], ")");
-
-                // 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
-            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)
-            }
 
             // Parentheses grouping
-            T!['('] => {
+            Token::LParen => {
-                // Contained inbetween the parentheses can be any other expression
+                let inner_expr = self.parse_expr();
-                let inner_expr = self.parse_expr()?;
 
                 // Verify that there is a closing parenthesis
-                validate_next!(self, T![')'], ")");
+                if !matches!(self.next(), Token::RParen) {
+                    panic!("Error parsing primary expr: Exepected closing parenthesis ')'");
+                }
 
                 inner_expr
             }
 
-            // Unary operations or invalid token
+            // Unary negation
-            tok => match tok.try_to_unop() {
+            Token::Sub => {
-                // If the token is a valid unary operation, parse it as such
+                let operand = self.parse_primary();
-                Some(uot) => Expression::UnOp(uot, self.parse_primary()?.into()),
+                Expression::UnOp(UnOpType::Negate, operand.into())
+            }
 
-                // Otherwise it's an unexpected token
+            // Unary bitwise not (bitflip)
-                None => return Err(ParseErr::UnexpectedToken(tok, "primary".to_string())),
+            Token::Tilde => {
-            },
+                let operand = self.parse_primary();
-        };
+                Expression::UnOp(UnOpType::BNot, operand.into())
+            }
 
-        Ok(primary)
+            // Unary logical not
+            Token::LNot => {
+                let operand = self.parse_primary();
+                Expression::UnOp(UnOpType::LNot, operand.into())
+            }
+
+            tok => panic!("Error parsing primary expr: Unexpected Token '{:?}'", tok),
+        }
     }
 
-    /// Try to get the position of a variable on the variable stack. This is needed to precalculate 
+    /// Get the next Token without removing it
-    /// 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 
-    /// the stackpositions in order to save time when executing
-    fn get_fun_stackpos(&self, varid: Sid) -> ResPE<usize> {
-        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 
-    /// returned. This follows the same reasoning as in the Lexer
     fn peek(&mut self) -> &Token {
-        self.tokens.peek().unwrap_or(&T![EoF])
+        self.tokens.peek().unwrap_or(&Token::EoF)
     }
 
-    /// Put a single token back into the token stream
+    /// Advance to next Token and return the removed Token
-    fn putback(&mut self, tok: Token) {
-        self.tokens.putback(tok);
-    }
-
-    /// Advance to next Token and return the removed Token. If there are no more tokens left, the 
-    /// EoF token is returned. This follows the same reasoning as in the Lexer
     fn next(&mut self) -> Token {
-        self.tokens.next().unwrap_or(T![EoF])
+        self.tokens.next().unwrap_or(Token::EoF)
     }
 }
 
 #[cfg(test)]
 mod tests {
+    use super::{parse, BinOpType, Expression};
     use crate::{
-        ast::{BinOpType, Expression, Statement},
+        parser::{Ast, Statement},
-        parser::parse,
+        token::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::I64(1),
-            T![+],
+            Token::Add,
-            T![i64(2)],
+            Token::I64(2),
-            T![*],
+            Token::Mul,
-            T![i64(3)],
+            Token::I64(3),
-            T![-],
+            Token::Sub,
-            T![i64(4)],
+            Token::I64(4),
-            T![;],
+            Token::Semicolon,
         ];
 
         let expected = Statement::Expr(Expression::BinOp(
@@ -583,9 +284,11 @@ mod tests {
             Expression::I64(4).into(),
         ));
 
-        let expected = vec![expected];
+        let expected = Ast {
+            prog: vec![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 +1,146 @@
-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),
-}
-
-/// Combined tokens that consist of a combination of characters
-#[derive(Debug, PartialEq, Eq)]
-pub enum Combo {
-    /// Equal Equal ("==")
-    Equal2,
-
-    /// Exclamation mark Equal ("!=")
-    ExclamationMarkEqual,
-
-    /// Ampersand Ampersand ("&&")
-    Ampersand2,
-
-    /// Pipe Pipe ("||")
-    Pipe2,
-
-    /// LessThan LessThan ("<<")
-    LessThan2,
-
-    /// 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
+    /// Integer literal (64-bit)
-    Literal(Literal),
+    I64(i64),
 
-    /// Keyword token
+    /// String literal
-    Keyword(Keyword),
+    String(String),
 
-    /// Identifier token (names for variables, functions, ...)
+    /// Identifier (name for variables, functions, ...)
     Ident(String),
 
-    /// Combined tokens consisting of multiple characters
+    /// Loop keyword (loop)
-    Combo(Combo),
+    Loop,
 
-    /// Comma (",")
+    /// Print keyword (print)
-    Comma,
+    Print,
 
-    /// Equal Sign ("=")
+    /// If keyword (if)
-    Equal,
+    If,
 
-    /// Semicolon (";")
+    /// Else keyword (else)
-    Semicolon,
+    Else,
 
-    /// End of file (This is not generated by the lexer, but the parser uses this to find the 
+    /// Left Parenthesis ('(')
-    /// end of the token stream)
-    EoF,
-
-    /// Left Bracket ("[")
-    LBracket,
-
-    /// Right Bracket ("]")
-    RBracket,
-
-    /// Left Parenthesis ("(")
     LParen,
 
-    /// Right Parenthesis (")"")
+    /// Right Parenthesis (')')
     RParen,
 
-    /// Left curly braces ("{")
+    /// Left curly braces ({)
     LBraces,
 
-    /// Right curly braces ("}")
+    /// Right curly braces (})
     RBraces,
 
-    /// Plus ("+")
+    /// Plus (+)
-    Plus,
+    Add,
 
-    /// Minus ("-")
+    /// Minus (-)
-    Minus,
+    Sub,
 
-    /// Asterisk ("*")
+    /// Asterisk (*)
-    Asterisk,
+    Mul,
 
-    /// Slash ("/")
+    /// Slash (/)
-    Slash,
+    Div,
 
-    /// Percent ("%")
+    /// Percent (%)
-    Percent,
+    Mod,
 
-    /// Pipe ("|")
+    /// Equal Equal (==)
-    Pipe,
+    EquEqu,
 
-    /// Tilde ("~")
+    /// Exclamationmark Equal (!=)
+    NotEqu,
+
+    /// Pipe (|)
+    BOr,
+
+    /// Ampersand (&)
+    BAnd,
+
+    /// Circumflex (^)
+    BXor,
+
+    /// Logical AND (&&)
+    LAnd,
+
+    /// Logical OR (||)
+    LOr,
+
+    /// Shift Left (<<)
+    Shl,
+
+    /// Shift Right (>>)
+    Shr,
+
+    /// Tilde (~)
     Tilde,
 
-    /// Logical not ("!")
+    /// Logical not (!)
-    Exclamationmark,
+    LNot,
 
-    /// Left angle bracket ("<")
+    /// Left angle bracket (<)
-    LessThan,
+    LAngle,
 
-    /// Right angle bracket (">")
+    /// Right angle bracket (>)
-    GreaterThan,
+    RAngle,
 
-    /// Ampersand ("&")
+    /// Left angle bracket Equal (<=)
-    Ampersand,
+    LAngleEqu,
 
-    /// Circumflex ("^")
+    /// Left angle bracket Equal (>=)
-    Circumflex,
+    RAngleEqu,
+
+    /// Left arrow (<-)
+    LArrow,
+
+    /// Equal Sign (=)
+    Equ,
+
+    /// 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::LAnd => BinOpType::LAnd,
-            T![||] => BinOpType::LOr,
+            Token::LOr => BinOpType::LOr,
 
-            T![<<] => BinOpType::Shl,
+            Token::Shl => BinOpType::Shl,
-            T![>>] => BinOpType::Shr,
+            Token::Shr => BinOpType::Shr,
 
-            T![==] => BinOpType::EquEqu,
+            Token::EquEqu => BinOpType::EquEqu,
-            T![!=] => BinOpType::NotEqu,
+            Token::NotEqu => BinOpType::NotEqu,
 
-            T![<] => BinOpType::Less,
+            Token::LAngle => BinOpType::Less,
-            T![<=] => BinOpType::LessEqu,
+            Token::LAngleEqu => BinOpType::LessEqu,
 
-            T![>] => BinOpType::Greater,
+            Token::RAngle => BinOpType::Greater,
-            T![>=] => BinOpType::GreaterEqu,
+            Token::RAngleEqu => BinOpType::GreaterEqu,
 
-            T![=] => BinOpType::Assign,
+            Token::LArrow => BinOpType::Declare,
-
+            Token::Equ => 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());
-        }
-    }
-}