472,958 Members | 2,059 Online
Bytes | Software Development & Data Engineering Community
Post Job

Home Posts Topics Members FAQ

Join Bytes to post your question to a community of 472,958 software developers and data experts.

Problem with dynamic creation of classes.

I have a base class B and a derived class D which inherits from B. I also
have a D2 class which inherits from D. D is used as a base class for most
of my generated classes. I have a "special" class which inherits from D2
because I need to override a couple of its methods. Anything based on D2
will inherit Encode and Decode from B.

class D(b.B):
def __init__(self, data, timestamp = None):
b.B.__init__(self, data)
self.timestamp = timestamp

class D2( D ):
def __init__(self, data, timestamp = None):
DS.__init__(self, data, timestamp)
def Decode(self):
pass
def Encode(self):
pass

The generated classes come from this loop:

for m in mdefs:
mdef = mdefs[m]
name = mdef['name'] + fbase
if mdef.has_key('baseclass'):
base_class_seq = mdef['baseclass']
else:
base_class_seq = DEFAULT_BASE_CLASS
nclass = new.classobj( name, base_class_seq, globals() )

base_class_seq is either going to be (D,) or (D2,)

After I get through the class generation, I want to say
globals()['IFRAMED2'].Decode = dynDecode
globals()['IFRAMED2'].Encode = dynEncode
for the one class that inherited from D2. If I do that, I find that *all*
classes that call Encode or Decode are all calling dyn{En,De}code (which
is exactly what I *don't* want).

So I looked at the id values after class generation.

print 'IFRAMED2.Encode = ', IFRAMED2.Encode, id(IFRAMED2.Encode)
print 'SNRMD.Encode = ', SNRMD.Encode, id(SNRMD.Encode)
print 'IFRAMED2 = ', IFRAMED2, id(IFRAMED2)
print 'SNRMD = ', SNRMD, id(SNRMD)
IFRAMED2.Decode = dynDecode
IFRAMED2.Encode = dynEncode
print 'IFRAMED2.Encode = ', IFRAMED2.Encode, id(IFRAMED2.Encode)
print 'SNRMD.Encode = ', SNRMD.Encode, id(SNRMD.Encode)

Here's the output:

IFRAMED2.Encode = <unbound method IFRAMED2.Encode1100623660
SNRMD.Encode = <unbound method SNRMD.Encode1100623660
IFRAMED2 = d.IFRAMED2 1076299644
SNRMD = d.SNRMD 1103202364
IFRAMED2.Encode = <unbound method IFRAMED2.dynEncode1100623660
SNRMD.Encode = <unbound method SNRMD.dynEncode1100623660

So it looks like the IFRAMED2 class which inherits from D2 is starting out
with the same id value for Encode as SNRMD which inherits from D, even
though D2 defines its own Encode method.

Is it me of is it the interpreter doing something wrong?

--
Time flies like the wind. Fruit flies like a banana. Stranger things have .0.
happened but none stranger than this. Does your driver's license say Organ ..0
Donor?Black holes are where God divided by zero. Listen to me! We are all- 000
individuals! What if this weren't a hypothetical question?
steveo at syslang.net
Aug 23 '07 #1
0 851

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

6
by: Andre Meyer | last post by:
Hi all I have been searching everywhere for this, but have not found a solution, yet. What I need is to create an object that is an instance of a class (NOT a class instance!) of which I only...
0
by: Pascal Costanza | last post by:
Dynamic Languages Day @ Vrije Universiteit Brussel ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Monday, February 13, 2006, VUB Campus Etterbeek The VUB (Programming Technology Lab,...
13
by: xian_hong2046 | last post by:
Hello, I think dynamic memory allocation is supposed to be used when one doesn't know in advance how much memory to allocate until run time. An example from Thinking in C++ is to dynamically...
1
by: Steven W. Orr | last post by:
Sorry, I had a small description problem. It's corrected below. I have a base class B and a derived class D which inherits from B. I also have a D2 class which inherits from D. D is used as a...
0
by: lllomh | last post by:
Define the method first this.state = { buttonBackgroundColor: 'green', isBlinking: false, // A new status is added to identify whether the button is blinking or not } autoStart=()=>{
2
by: DJRhino | last post by:
Was curious if anyone else was having this same issue or not.... I was just Up/Down graded to windows 11 and now my access combo boxes are not acting right. With win 10 I could start typing...
2
isladogs
by: isladogs | last post by:
The next Access Europe meeting will be on Wednesday 4 Oct 2023 starting at 18:00 UK time (6PM UTC+1) and finishing at about 19:15 (7.15PM) The start time is equivalent to 19:00 (7PM) in Central...
2
by: giovanniandrean | last post by:
The energy model is structured as follows and uses excel sheets to give input data: 1-Utility.py contains all the functions needed to calculate the variables and other minor things (mentions...
3
NeoPa
by: NeoPa | last post by:
Introduction For this article I'll be using a very simple database which has Form (clsForm) & Report (clsReport) classes that simply handle making the calling Form invisible until the Form, or all...
1
by: Teri B | last post by:
Hi, I have created a sub-form Roles. In my course form the user selects the roles assigned to the course. 0ne-to-many. One course many roles. Then I created a report based on the Course form and...
3
by: nia12 | last post by:
Hi there, I am very new to Access so apologies if any of this is obvious/not clear. I am creating a data collection tool for health care employees to complete. It consists of a number of...
0
isladogs
by: isladogs | last post by:
The next online meeting of the Access Europe User Group will be on Wednesday 6 Dec 2023 starting at 18:00 UK time (6PM UTC) and finishing at about 19:15 (7.15PM). In this month's session, Mike...
2
by: GKJR | last post by:
Does anyone have a recommendation to build a standalone application to replace an Access database? I have my bookkeeping software I developed in Access that I would like to make available to other...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.