example #166 update example to use base class AND metaclass

tests/trial/bacon.py

@@ -8,16 +8,16 @@
 * https://www.pythoncentral.io/how-metaclasses-work-technically-in-python-2-and-3/
 """
 
-from plugin_base import Plugin
+from plugin_base import AutoRegister, Parent
 
-class File(metaclass=Plugin):
+class File(Parent, metaclass=AutoRegister):
     key = "#F"
 
-class Date(metaclass=Plugin):
+class Date(Parent, metaclass=AutoRegister):
     key = "#D"
 
-class Epoch(metaclass=Plugin):
+class Epoch(Parent, metaclass=AutoRegister):
     key = "#E"
 
-class Comment(metaclass=Plugin):
+class Comment(Parent, metaclass=AutoRegister):
     key = "#C"

tests/trial/example.py

@@ -19,7 +19,8 @@
 
 # loop over registered plugins
 for key, cls in plugins.get_registry().items():
-    if cls is not plugins.plugin_base.Plugin:
-        logger.info(f"key={key}  class={cls}")
+    if cls is not plugins.plugin_base.AutoRegister:
+        obj = cls()
+        logger.info(f"key={key}  class={cls}  obj={obj}")
 
 logger.info("-"*40)

tests/trial/plugin_base.py

@@ -43,7 +43,7 @@ def register_plugin(cls):
     registry[key] = cls
 
 
-class Plugin(type):
+class AutoRegister(type):
     __key__ = None
     def __init__(cls, name, bases, dict):
         logger.debug(" "*4 + "."*10)
@@ -60,3 +60,11 @@ def __new__(metaname, classname, baseclasses, attrs):
         logger.debug(f'__new__: baseclasses={baseclasses}')
         logger.debug(f'__new__: attrs={attrs}')
         return type.__new__(metaname, classname, baseclasses, attrs)
+
+
+class Parent:
+    key = None
+    def __str__(self):
+        return(f"{self.__class__.__name__}(key='{self.key}')")
+    def do_this(self):
+        print(self.__class__.__name__)

tests/trial/spam.py

@@ -8,7 +8,7 @@
 * https://www.pythoncentral.io/how-metaclasses-work-technically-in-python-2-and-3/
 """
 
-from plugin_base import Plugin
+from plugin_base import AutoRegister, Parent
 
-class Scan(metaclass=Plugin):
+class Scan(Parent, metaclass=AutoRegister):
     key = "#S"