metaprogramming examples

descriptors/bulkfood_v4.py

@@ -45,23 +45,23 @@ class Quantity:
 
     def __init__(self):
         cls = self.__class__  # <2>
-        prefix = cls.__name__  # <3>
-        index = cls.__counter  # <4>
-        self.storage_name = '_{}_{}'.format(prefix, index)  # <5>
-        cls.__counter += 1  # <6>
+        prefix = cls.__name__
+        index = cls.__counter
+        self.storage_name = '_{}_{}'.format(prefix, index)  # <3>
+        cls.__counter += 1  # <4>
 
-    def __get__(self, instance, owner):  # <7>
-        return getattr(instance, self.storage_name)  # <8>
+    def __get__(self, instance, owner):  # <5>
+        return getattr(instance, self.storage_name)  # <6>
 
-    def __set__(self, instance, value):  # <9>
+    def __set__(self, instance, value):
         if value > 0:
-            setattr(instance, self.storage_name, value)  # <10>
+            setattr(instance, self.storage_name, value)  # <7>
         else:
             raise ValueError('value must be > 0')
 
 
 class LineItem:
-    weight = Quantity()  # <11>
+    weight = Quantity()  # <8>
     price = Quantity()
 
     def __init__(self, description, weight, price):
@@ -71,4 +71,4 @@ class LineItem:
 
     def subtotal(self):
         return self.weight * self.price
-# END LINEITEM_V4
+# END LINEITEM_V4