__dict__ for instances?

[Ivan Voras]

While using PyGTK, I want to try and define signal handlers
automagically, without explicitly writing the long dictionary (i.e. I
want to use signal_autoconnect()).

To do this, I need something that will inspect the current "self" and
return a dictionary that looks like:

{
"method_name" : self.method_name
}

Class.__dict__ does something very similar, but when I use it, either
I'm doing something wrong or it doesn't return methods bound to "self",
and python complains a wrong number of arguments is being passed to the
methods (one instead of two).

instance.__dict__ on the other hand returns an empty dictionary.

This looks like it should be easy, but I can't find the solution

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[half.italian]

While using PyGTK, I want to try and define signal handlers
automagically, without explicitly writing the long dictionary (i.e. I
want to use signal_autoconnect()).

To do this, I need something that will inspect the current "self" and
return a dictionary that looks like:

{
"method_name" : self.method_name

}

Class.__dict__ does something very similar, but when I use it, either
I'm doing something wrong or it doesn't return methods bound to "self",
and python complains a wrong number of arguments is being passed to the
methods (one instead of two).

instance.__dict__ on the other hand returns an empty dictionary.

This looks like it should be easy, but I can't find the solution

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I think you want "dir(instance)" __dict__ returns the instance
variables and values as a dictionary, but doesn't return methods.
dir() returns a list of the instance's methods and variables. Then
you'd need to iterate over the list with type() looking for instance
methods

instance = Class.Class()
dict = {}
methods = [f for f in dir(instance) if str(type(instance.f)) == "<type
'instancemethod'>"]
for m in methods:
dict[m.name] = m

The above is untested. I'm sure there is a better way to do this.

~Sean

 

[Ivan Voras]

I think you want "dir(instance)" __dict__ returns the instance

Part of the problem is that dir(instance) returns a list of strings, so
iterating the dir(instance) gets me strings, not methods. Alternatively,
is there a way to get a "bound" instance by its name - some
introspection function perhaps?

variables and values as a dictionary, but doesn't return methods.

It does on a Class

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[Bruno Desthuilliers]

Ivan Voras a écrit :

Part of the problem is that dir(instance) returns a list of strings, so
iterating the dir(instance) gets me strings, not methods. Alternatively,
is there a way to get a "bound" instance by its name - some
introspection function perhaps?

getattr(obj, name)

It does on a Class

Usually, methods are attributes of the class, not of the instance.

 

[Bruno Desthuilliers]

Ivan Voras a écrit :

While using PyGTK, I want to try and define signal handlers
automagically, without explicitly writing the long dictionary (i.e. I
want to use signal_autoconnect()).

To do this, I need something that will inspect the current "self" and
return a dictionary that looks like:

{
"method_name" : self.method_name
}

Class.__dict__ does something very similar, but when I use it, either
I'm doing something wrong or it doesn't return methods bound to "self",
and python complains a wrong number of arguments is being passed to the
methods (one instead of two).

You're not doing anything wrong, that's just how Python works. "methods"
are wrapper objects around function objects attributes. The wrapping
only happens at lookup time, and returns different kind of "method"
wrapper (resp. unbound or bound methods) if the attribute is looked up
on an instance or a class (there are also the staticmethod/classmethod
things, but that's not your problem here).

You can build the dict you're looking for using dir() and getattr():

from types import MethodType

autoconnect_dict = {}
for name in dir(self):
attr = getattr(self, name)
if isinstance(attr, MethodType):
autoconnect_dict[name] = attr
return autoconnect_dict

instance.__dict__ on the other hand returns an empty dictionary.

the instance's __dict__ only stores per-instance attributes. While it's
technically possible to attach methods per-instance, it's definitively a
corner case.

 

[Marc Christiansen]

While using PyGTK, I want to try and define signal handlers
automagically, without explicitly writing the long dictionary (i.e. I
want to use signal_autoconnect()).

To do this, I need something that will inspect the current "self" and
return a dictionary that looks like:

{
"method_name" : self.method_name
}

Nope, at least for PyGTK 2 See below.

[...]

This looks like it should be easy, but I can't find the solution

Use the doc, Luke, oops, Ivan
Citing the gtk.glade.XML.signal_autoconnect documentation:
def signal_autoconnect(dict)
dict: a mapping or an instance
^^^^^^^^

The signal_autoconnect() method is a variation of the
gtk.glade.XML.signal_connect method. It uses Python's introspective
features to look at the keys (if dict is a mapping) or attributes (if
^^^^^^^^^^^^^^
dict is an instance) and tries to match them with the signal handler
^^^^^^^^^^^^^^^^^^^
names given in the interface description. The callbacks referenced by
each matched key or attribute are connected to their matching signals.
The argument is called dict due to compatibility reasons since
originally only the mapping interface was supported. The instance
variant was introduced in PyGTK 2.0.

So simply using signal_autoconnect(self) should work.

AdiaÅ­, Marc

 

[half.italian]

Part of the problem is that dir(instance) returns a list of strings, so
iterating the dir(instance) gets me strings, not methods. Alternatively,
is there a way to get a "bound" instance by its name - some
introspection function perhaps?


It does on a Class

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I tried.

~Sean

 

[Ivan Voras]

Nope, at least for PyGTK 2 See below.

Aaah, but....!

[...]

This looks like it should be easy, but I can't find the solution

Use the doc, Luke, oops, Ivan
Citing the gtk.glade.XML.signal_autoconnect documentation:
def signal_autoconnect(dict)
dict: a mapping or an instance
^^^^^^^^

I should have mentioned - I tried it already and it didn't work. The
specific error I get is:

"WARNING: "on_button_clicked" not callable or a tuple"

once for each handler when I call autoconnect. And I've got a recent
version of pyGTK (2.10.4) so it should.


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[Ivan Voras]

You're not doing anything wrong, that's just how Python works. "methods"
are wrapper objects around function objects attributes. The wrapping
only happens at lookup time, and returns different kind of "method"
wrapper (resp. unbound or bound methods) if the attribute is looked up
on an instance or a class (there are also the staticmethod/classmethod
things, but that's not your problem here).

Got it, thanks for the explanation!



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[Bruno Desthuilliers]

Ivan Voras a écrit :

Marc Christiansen wrote:

Nope, at least for PyGTK 2 See below.

Aaah, but....!

[...]

This looks like it should be easy, but I can't find the solution

Use the doc, Luke, oops, Ivan
Citing the gtk.glade.XML.signal_autoconnect documentation:
def signal_autoconnect(dict)
dict: a mapping or an instance
^^^^^^^^

I should have mentioned - I tried it already and it didn't work. The
specific error I get is:

"WARNING: "on_button_clicked" not callable or a tuple"

Please post the relevant code and the full traceback.

 

[Ivan Voras]

Please post the relevant code and the full traceback.

The code:

Class W:
def __init__(self):
self.xml = gtk.glade.XML("glade/mainwin.glade")
self.window = self.xml.get_widget("mainwin")
self.xml.signal_autoconnect(self)

w = W()
gtk.main()

The error (not an exception, only the message appears and the handler
doesn't work):

** (finstall.py:7551): WARNING **: handler for 'on_button_next_clicked'
not callable or a tuple

(the file has some 20 lines, not 7551)


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[Bruno Desthuilliers]

Ivan Voras a écrit :

The code:

Class W:
def __init__(self):
self.xml = gtk.glade.XML("glade/mainwin.glade")
self.window = self.xml.get_widget("mainwin")
self.xml.signal_autoconnect(self)

w = W()
gtk.main()

The error (not an exception, only the message appears and the handler
doesn't work):

** (finstall.py:7551): WARNING **: handler for 'on_button_next_clicked'
not callable or a tuple

Is this the full message, or did you skip the preceding lines ?

(the file has some 20 lines, not 7551)

Is "finstall.py" the name of your file ? If yes, I'd suspect something
wrong with your sys.path or like...

 

[Ivan Voras]

Is this the full message, or did you skip the preceding lines ?

The full message.

Is "finstall.py" the name of your file ? If yes, I'd suspect something
wrong with your sys.path or like...

This is the name of my file - and it IS executed, only the error message
is weird.


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