parser little done and fix more bugs

src/nodes/binary_op.py

@@ -3,22 +3,20 @@
 class BinaryOperation(Node):
     def __init__(self, left, op, right):
         self.left = left
-        self.op = self.op
-        self.right = self.right
+        self.op = op
+        self.right = right
 
     def __repr__(self):
-        return {
+        return str({
             "BinaryOperation": self.op,
             "Left": self.left,
             "Right": self.right
-        }
+        })
 
-    def __str__(self):
-        return str(self.__repr__())
 
 class Add(BinaryOperation):
     def __init__(self, left, right):
-        super().__init__(left, "+", right)
+        super().__init__(left=left, op="+", right=right)
 
 class Subtract(BinaryOperation):
     def __init__(self, left, right):

src/nodes/number.py

@@ -27,4 +27,5 @@ def to_latex(self):
     def __float__(self):
         return float(self.value)
 
-
+    def __repr__(self):
+        return str({"Number": self.value})

src/parser.py

@@ -1,8 +1,67 @@
 from nodes import *
 
+"""
+TODO:
+basic arithmetic
+parenthesis
+one-line function definition
+function calls
+coefficiet-symbol
+parenthesis means multiplication ( well sometimes )
+statement separation
+variable assignments
+equation
+inequality
+
+data-strctures:
+    matrices
+    hash-maps/dicts
+    sets
+
+
+more later
+"""
 class Parser:
     def __init__(self, tokens: list):
-        self.tokens = tokens
+        self.tokens = iter(tokens)
+        self.current_token = next(self.tokens)
+
+    def advance(self):
+        try:
+            self.current_token = next(self.tokens)
+        except StopIteration:
+            self.current_token = None
 
     def parse(self):
-        pass
+        node = self.parse_expression() 
+        return node
+
+    def parse_expression(self):
+        node = self.parse_term()
+
+        while self.current_token != None and self.current_token.value in ("+", "-"):
+            operator_ = globals()[self.current_token.name]
+            self.advance()
+            right = self.parse_term()
+            node = operator_(left=node, right=right) # Add(left, right) or Subtract(left, right)
+        return node
+
+    def parse_term(self):
+        node = self.parse_factor()
+
+        while self.current_token != None and self.current_token.value in ("*", "/"):
+            operator_ = globals()[self.current_token.name]
+            self.advance()
+            right = self.parse_factor()
+            node = operator_(left=node, right=node)
+
+        return node
+
+    def parse_factor(self):
+        node = None
+
+        if self.current_token.name == "Number":
+            node = Number(self.current_token.value)
+            self.advance()
+        return node
+