From 458120dd40db6b4df55a4e96b650e16798ef06a0 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@localhost>
Date: Tue, 3 May 2011 11:25:13 +0000
Subject: add hg and python

---
 sys/src/cmd/python/Demo/metaclasses/Simple.py | 45 +++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 sys/src/cmd/python/Demo/metaclasses/Simple.py

(limited to 'sys/src/cmd/python/Demo/metaclasses/Simple.py')

diff --git a/sys/src/cmd/python/Demo/metaclasses/Simple.py b/sys/src/cmd/python/Demo/metaclasses/Simple.py
new file mode 100644
index 000000000..03ed2592e
--- /dev/null
+++ b/sys/src/cmd/python/Demo/metaclasses/Simple.py
@@ -0,0 +1,45 @@
+import types
+
+class Tracing:
+    def __init__(self, name, bases, namespace):
+        """Create a new class."""
+        self.__name__ = name
+        self.__bases__ = bases
+        self.__namespace__ = namespace
+    def __call__(self):
+        """Create a new instance."""
+        return Instance(self)
+
+class Instance:
+    def __init__(self, klass):
+        self.__klass__ = klass
+    def __getattr__(self, name):
+        try:
+            value = self.__klass__.__namespace__[name]
+        except KeyError:
+            raise AttributeError, name
+        if type(value) is not types.FunctionType:
+            return value
+        return BoundMethod(value, self)
+
+class BoundMethod:
+    def __init__(self, function, instance):
+        self.function = function
+        self.instance = instance
+    def __call__(self, *args):
+        print "calling", self.function, "for", self.instance, "with", args
+        return apply(self.function, (self.instance,) + args)
+
+Trace = Tracing('Trace', (), {})
+
+class MyTracedClass(Trace):
+    def method1(self, a):
+        self.a = a
+    def method2(self):
+        return self.a
+
+aninstance = MyTracedClass()
+
+aninstance.method1(10)
+
+print aninstance.method2()
-- 
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