ex 7.7

rhasti · rhasti · commit ae9d02a54338 · 2021-12-04T12:51:40.000+01:00
diff --git a/Work/stock.py b/Work/stock.py
@@ -1,10 +1,12 @@
-from sys import settrace
+from typedproperty import typedproperty
 
 
 class Stock:
-    __slots__ = ("name", "_shares", "price")
+    name = typedproperty("name", str)
+    shares = typedproperty("shares", int)
+    price = typedproperty("price", float)
 
-    def __init__(self, name: str, shares: int, price: float) -> None:
+    def __init__(self, name, shares, price) -> None:
         self.name = name
         self._shares = shares
         self.price = price
@@ -16,15 +18,13 @@ def __repr__(self) -> str:
     def cost(self):
         return self.shares * self.price
 
-    @property
-    def shares(self):
-        return self._shares
+    # @property
+    # def shares(self):
+    #     return self._shares
 
-    @shares.setter
-    def shares(self, shares):
-        if not isinstance(shares, int):
-            raise TypeError("expected an integer")
-        self._shares = shares
+    # @shares.setter
+    # def shares(self, shares):
+    #     self._shares = shares
 
     def sell(self, amount):
         if amount <= self.shares:
diff --git a/Work/typedproperty.py b/Work/typedproperty.py
@@ -0,0 +1,17 @@
+# typedproperty.py
+
+
+def typedproperty(name, expected_type):
+    private_name = "_" + name
+
+    @property
+    def prop(self):
+        return getattr(self, private_name)
+
+    @prop.setter
+    def prop(self, value):
+        if not isinstance(value, expected_type):
+            raise TypeError(f"Expected {expected_type}")
+        setattr(self, private_name, value)
+
+    return prop
