encapsulate type token type checking

interpreter/app/ast/ast.py

@@ -30,7 +30,7 @@ def __init__(self):
         self.current_operator = self.root
 
     def feed(self, token):
-        if isinstance(token, OperatorToken):
+        if token.is_operator():
             self._feed_operator(token)
         else:
             self._feed_number(token)

interpreter/app/interpreter/interpreter.py

@@ -77,7 +77,7 @@ def advance_token(self):
         self.current_token = next_token
 
     def done(self):
-        return isinstance(self.current_token, token.EOFToken)
+        return self.current_token.is_a(token.EOF)
 
     def eat(self, *token_types):
         """
@@ -121,9 +121,9 @@ def expr(self):
         ast = AST()
 
         while not self.done():
-            if isinstance(self.current_token, token.OperatorToken):
+            if self.current_token.is_operator():
                 ast.feed(self.eat_operator())
-            elif isinstance(self.current_token, token.SpaceToken):
+            elif self.current_token.is_a(token.SPACE):
                 self.advance_token()
             else:
                 ast.feed(self.eat_integers())

interpreter/app/token/token.py

@@ -25,7 +25,19 @@ def __str__(self):
     def __repr__(self):
         return self.__str__()
 
-class SpaceToken(object):
+    def is_a(self, type: str) -> bool:
+        """
+        Returns if token is of the same type as `type`
+        Example:
+            token.is_a('INTEGER')
+        """
+
+        return self.type == type
+
+    def is_operator(self) -> bool:
+        return isinstance(self, OperatorToken)
+
+class SpaceToken(Token):
     def __init__(self) -> None:
         self.type = SPACE
         self.value = None