-

cool-RR · cool-RR · commit 492b467bc315 · 2013-10-06T21:08:14.000+03:00
diff --git a/source_py3/python_toolbox/misc_tools/__init__.py b/source_py3/python_toolbox/misc_tools/__init__.py
@@ -8,7 +8,7 @@
     _ascii_variable_pattern, is_legal_ascii_variable_name,
     is_magic_variable_name, get_actual_type, is_number, identity_function,
     do_nothing, OwnNameDiscoveringDescriptor, find_clear_place_on_circle,
-    general_sum, general_product, is_legal_email_address, is_type
+    general_sum, general_product, is_legal_email_address, is_type, NonInstatiable
 )
 from . import name_mangling
 from .proxy_property import ProxyProperty
diff --git a/source_py3/python_toolbox/misc_tools/misc_tools.py b/source_py3/python_toolbox/misc_tools/misc_tools.py
@@ -267,3 +267,13 @@ def is_type(thing):
     '''Is `thing` a class? Allowing both new-style and old-style classes.'''
     return isinstance(thing, type)
 
+
+class NonInstatiable:
+    '''
+    Class that can't be instatiated.
+    
+    Inherit from this for classes that should never be instantiated, like
+    constants and settings.
+    '''
+    def __new__(self, *args, **kwargs):
+        raise RuntimeError('This class may not be instatiated.')
diff --git a/source_py3/test_python_toolbox/test_misc_tools/test_non_instantiable.py b/source_py3/test_python_toolbox/test_misc_tools/test_non_instantiable.py
@@ -0,0 +1,14 @@
+# Copyright 2009-2013 Ram Rachum.
+# This program is distributed under the MIT license.
+
+from python_toolbox import cute_testing
+
+from python_toolbox.misc_tools import NonInstatiable
+
+
+def test():
+    class MyNonInstatiable(NonInstatiable):
+        pass
+    
+    with cute_testing.RaiseAssertor(exception_type=RuntimeError):
+        MyNonInstatiable()

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`_ascii_variable_pattern, is_legal_ascii_variable_name,`
`9`	`9`	`is_magic_variable_name, get_actual_type, is_number, identity_function,`
`10`	`10`	`do_nothing, OwnNameDiscoveringDescriptor, find_clear_place_on_circle,`
`11`		`- general_sum, general_product, is_legal_email_address, is_type`
	`11`	`+ general_sum, general_product, is_legal_email_address, is_type, NonInstatiable`
`12`	`12`	`)`
`13`	`13`	`from . import name_mangling`
`14`	`14`	`from .proxy_property import ProxyProperty`