py: Initial attempts to actually allow implementing __new__ in Python.

Caveat is that __new__ should recurse to base class __new__, and ultimately,
object.__new__ is what handles instance allocation.
This commit is contained in:
Paul Sokolovsky
2014-05-22 00:32:00 +03:00
parent 0c937fa25a
commit 806ea1f6ca
4 changed files with 64 additions and 2 deletions

View File

@@ -0,0 +1,20 @@
# object.__new__(cls) is the only way in Python to allocate empty
# (non-initialized) instance of class.
# See e.g. http://infohost.nmt.edu/tcc/help/pubs/python/web/new-new-method.html
# TODO: Find reference in CPython docs
class Foo:
def __init__(self):
print("in __init__")
self.attr = "something"
o = object.__new__(Foo)
#print(o)
print(hasattr(o, "attr"))
print(isinstance(o, Foo))
o.__init__()
#print(dir(o))
print(hasattr(o, "attr"))
print(o.attr)