added listtree.py

progrmoiz · progrmoiz · commit c80c16d1dcd3 · 2017-12-11T21:43:40.000+05:00
diff --git a/listtree.py b/listtree.py
@@ -0,0 +1,81 @@
+#!/usr/bin/env python3
+# File listtree.py (2.x + 3.x)
+
+
+class ListTree:
+    """
+    Mix-in that returns an __str__ trace of the entire class and all
+    its object's attrs at and above self; run by print(), str() returns
+    constructed string; uses __X attr names to avoid impacting clients;
+    recurses to superclasses explicitly, uses str.format() for clarity.
+    """
+
+    def __attrnames(self, obj, indent):
+        spaces = ' ' * (indent + 1)
+        result = ''
+        for attr in sorted(obj.__dict__):
+            if attr.startswith('__') and attr.endswith('__'):
+                result += spaces + '{0}\n'.format(attr)
+            else:
+                result += spaces + '{0}={1}\n'.format(attr, getattr(obj, attr))
+        return result
+
+    def __listclass(self, aClass, indent):
+        dots = '.' * indent
+        if aClass in self.__visited:
+            return '\n{0}<Class {1}:, address {2}: (see above)>\n'.format(
+                dots,
+                aClass.__name__,
+                id(aClass))
+        else:
+            self.__visited[aClass] = True
+            here = self.__attrnames(aClass, indent)
+            above = ''
+            for super in aClass.__bases__:
+                above += self.__listclass(super, indent + 4)
+            return '\n{0}<Class {1}:, address {2}:\n{3}{4}{5}'.format(
+                dots,
+                aClass.__name__,
+                id(aClass),
+                here, above,
+                dots)
+
+    def __str__(self):
+        self.__visited = {}
+        here = self.__attrnames(self, 0)
+        above = self.__listclass(self.__class__, 4)
+        return '<Instance of {0}, address {1}:\n{2}{3}>'.format(
+            self.__class__.__name__,
+            id(self),
+            here, above)
+
+
+def tester(listerclass, sept=False):
+
+    class Super:
+
+        def __init__(self):
+            self.data1 = 'spam'
+
+        def ham(self):
+            pass
+
+    class Sub(Super, listerclass):
+
+        def __init__(self):
+            Super.__init__(self)
+            self.data2 = 'eggs'
+            self.data3 = 42
+
+        def spam(self):
+            pass
+
+    instance = Sub()
+    print(instance)
+    if sept:
+        print('-' * 80)
+
+
+if __name__ == '__main__':
+
+    tester(ListTree)
