Re: Python, Possibly OO, Terminology Question

  • From: David Tseng <davidct1209@xxxxxxxxx>
  • To: programmingblind@xxxxxxxxxxxxx
  • Date: Fri, 29 Jul 2011 17:27:45 -0700

Agreed on that one Ken :).

Sina, you should know better...the technical description of what I
wrote *is* a lambda expression (at least the outer anonymous
javascript function) but in context, a more apt term would be "lexical
closure" for the inner function which was the point of the example.

I totally agree on your suggestion to read up on theory; it's helped
me quite a lot out in industry though it's kind of unrealistic for
those without a formal background.
We should get everyone to start citing sources when they make claims
:) as you also neglected to do.

On 7/29/11, Ken Perry <whistler@xxxxxxxxxxxxx> wrote:
> I agree as I said before I use function for most anything like a function.
> The point I am trying to so badly make is knowing what you are talking about
> is important so at least getting close is important.
>
>
> Ken
>
> -----Original Message-----
> From: programmingblind-bounce@xxxxxxxxxxxxx
> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of David Tseng
> Sent: Friday, July 29, 2011 5:46 PM
> To: programmingblind@xxxxxxxxxxxxx
> Subject: Re: Python, Possibly OO, Terminology Question
>
> Right, but if you bind it to say window....
> window.SimpleArith = SimpleArith
>
> within the closure, you actually bind the "function" to the window's
> scope and thus accessible outside of the empty namespace.
>
> I'm not disagreeing with you, just trying to say that I don't think
> there's a precise definition for the terms everyone's throwing out
> there.  They're very soft terms for some real and well-defined
> concepts.
>
> On 7/29/11, Ken Perry <whistler@xxxxxxxxxxxxx> wrote:
>>
>> What that is called is javascript enclosure functions that is my point
>> though you need to understand what they are so if you say it's a class
>> function then it's really a method but if it's a function as you just did
>> it's an enclosed function.  Words do mean things and to say just call them
>> all functions because they are the same thing is wrong.  For example if I
>> did what you did below and told someone I wrote a function they would be
>> shocked to find they couldn't access it because I didn't tell them it was
>> enclosed.
>>
>> ken
>>
>> -----Original Message-----
>> From: programmingblind-bounce@xxxxxxxxxxxxx
>> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of David Tseng
>> Sent: Friday, July 29, 2011 5:00 PM
>> To: programmingblind@xxxxxxxxxxxxx
>> Subject: Re: Python, Possibly OO, Terminology Question
>>
>> Call it whatever you want...as long as you have a firm grasp of the
>> underlying concepts relating to OOP or functional programming, you'll
>> be just fine.
>>
>> Tell me what the following is:
>> function () {
>>   function SimpleArith() {
>>     'Add': function(a,b) { return a + b; },
>>     'Sub': function(a,b) { return a - b; },
>>     'PI':3.14,
>>   };
>> };
>>
>> function Compute(a,b) {...}
>>
>> They're all called functions...namespaces, classes, methods, functions...
>>
>> On 7/29/11, Ken Perry <whistler@xxxxxxxxxxxxx> wrote:
>>> I will say one more thing.  If you search for this "difference between
>>> function and method"  you will find lots of people that will argue this
>>> point over and over.  In fact you will find most of them that say it
> don't
>>> matter but I want to drop some code right here.  There is one language
>> that
>>> definitely is both functional and object oriented and that is c++ so look
>> at
>>> this code
>>>
>>> Class  myClass{
>>> Int b=0;
>>> Void aThing(int a){b=a};
>>> }
>>>
>>> Int b=0;
>>> Void aThing(int a){
>>> B=a;
>>> }
>>>
>>> Now to use the aThing in the first you must instantiate the class and use
>> it
>>> from the class to use the second aThing you don't have to.  One is called
>> a
>>> function to distinguish it from the other.  It's still a function but
> it's
>> a
>>> method because it's part of a classs.  So go ahead call it whatever you
>> like
>>> but the fact is there is a major difference.  Not only is there a
>> difference
>>> but it matters in languages when you have both functional and objects in
>> the
>>> same language because the top two could be in the same program in the
> same
>>> c++ file and they are different.
>>>
>>> ken
>>>
>>>
>>> -----Original Message-----
>>> From: programmingblind-bounce@xxxxxxxxxxxxx
>>> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Johannes Grib
>>> Sent: Friday, July 29, 2011 6:45 AM
>>> To: programmingblind@xxxxxxxxxxxxx
>>> Subject: RE: Python, Possibly OO, Terminology Question
>>>
>>> Hi Ken PerryPerry,
>>> Perhaps you might want to cite references please as documentation state
>> the
>>> following:
>>>
>>>
>>> The class contains the methods. A method is a function or module that is
>>> owned by the class. Depending on the programming language you're using,
>>> method, function, module, subroutine may all be used interchangeably.
>>>
>>> This supports Kerneels's "wrong" answer.
>>>
>>> Kindest
>>> Johannes
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: programmingblind-bounce@xxxxxxxxxxxxx
>>> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Ken Perry
>>> Sent: Friday, July 29, 2011 12:29
>>> To: programmingblind@xxxxxxxxxxxxx
>>> Subject: RE: Python, Possibly OO, Terminology Question
>>>
>>>
>>> Well if you want me to I will
>>> You said,
>>> "> in fact want to distinguish between them you could use "method" for
>>>> something that doesn't return anything (a void function) and use
>>>> "function" when something is returned, but it really doesn't matter
>>>> much since it's just documentation particulars."
>>>
>>> That was wrong that is the descriptions between a procedure and an
>> function
>>> like I said in my email.  Also there is a difference between function and
>>> method it's not just a documentation thing another wrong statement. For
>>> example it would be the same thing saying a member is the same thing as a
>>> class.  While a member of a class is a  variable it is a variable
> attached
>>> to a class as a method is a function attached to a class.
>>>
>>>
>>> -----Original Message-----
>>> From: programmingblind-bounce@xxxxxxxxxxxxx
>>> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Kerneels Roos
>>> Sent: Friday, July 29, 2011 3:34 AM
>>> To: programmingblind@xxxxxxxxxxxxx
>>> Subject: Re: Python, Possibly OO, Terminology Question
>>>
>>> I did say "please correct me if I'm wrong" but I was referring to the
>>> Python stuff really. So where is my answer wrong please? I don't think
>>> my answer was a wrong or right kind of answer actually -- it's about
>>> preference and style (excluding the Python specifics).
>>>
>>> Also made it quite clear that it doesn't really matter if you use the
>>> term "method" or "function" since they are used interchangeably and mean
>>> the same thing, or more importantly, you can't draw any serious
>>> conclusion if someone uses one or the other right?
>>>
>>> Simply saying "the previous answer is wrong" is too vague for me at
>>> leastThe statement about procedures, that we used to call functions that
>>> didn't return anything "procedures" -- yeah, I can remember that from
>>> Pascal also. Wasn't it the case that if you used the keyword "Procedure"
>>> you couldn't return anything, while when you used "Function" you were
>>> forced to return something?
>>> Thanks for pointing that out.
>>>
>>> Maybe it's one of those things there is no true consensus about? Would
>>> any "real" professor venture a comment here?
>>>
>>> Regards
>>>
>>> On 7/28/2011 2:19 PM, Ken Perry wrote:
>>>>
>>>> The previous answer was wrong.  We used to call functions that return
>>>> nothing a procedure but that is in languages like pascal but the
>> following
>>>> is the real answer for what is a function verses method.
>>>>
>>>> A function is a piece of code that is called by name. It can be passed
>>> data
>>>> to operate on (ie. the parameters) and can optionally return data (the
>>>> return value).
>>>>
>>>> All data that is passed to a function is explicitly passed.
>>>>
>>>> A method is a piece of code that is called by name that is associated
>> with
>>>> an object. In most respects it is identical to a function except for two
>>> key
>>>> differences.
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: programmingblind-bounce@xxxxxxxxxxxxx
>>>> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Homme, James
>>>> Sent: Thursday, July 28, 2011 6:59 AM
>>>> To: programmingblind@xxxxxxxxxxxxx
>>>> Subject: RE: Python, Possibly OO, Terminology Question
>>>>
>>>> Hi All,
>>>> Thanks for trying to answer. I'll just keep coding and eventually I'll
>>>> either understand or not.
>>>>
>>>> Jim
>>>>
>>>> -----Original Message-----
>>>> From: programmingblind-bounce@xxxxxxxxxxxxx
>>>> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Kerneels
> Roos
>>>> Sent: Thursday, July 28, 2011 3:48 AM
>>>> To: programmingblind@xxxxxxxxxxxxx
>>>> Subject: Re: Python, Possibly OO, Terminology Question
>>>>
>>>> Jim, and otheres, I agree that "method" and "function" are used
>>>> interchangeably and mean the same thing usually, but I think if you do
>>>> in fact want to distiguish between them you could use "method" for
>>>> something that doesn't return anything (a void function) and use
>>>> "function" when something is returned, but it really doesn't matter much
>>>> since it's just documentation particulars.
>>>>
>>>> In OO terminology people seem to prefer method over function (in my
>>>> experience).
>>>>
>>>> What is more important is to understand the difference between class and
>>>> instance methods, which, coming from Java such as yourself is simple to
>>>> grasp. In computer science it helps to distinguish terminology from
>>>> implementation particulars since languages can and do use varied terms
>>>> for intrinsically the same thing. Some times the language uses the right
>>>> terminology, or the most widely accepted terminology, but ti's not a
>>> given.
>>>>
>>>> Now, to get back to Python, it seems there are three types of methods
>>>> (and please correct me here if I'm wrong):
>>>>
>>>> @staticmethod
>>>> def some_static_method (param1, param2):
>>>>       # do something not involving an instance of the class this method
>>>> is in, except other static items perhaps
>>>>
>>>> So this looks like the class method (OO terminology) which you get in
>>>> Java by adding the "static" method attribute to your method is it not?
>>>>
>>>> @classmethod
>>>> def some_class_method (cls):
>>>>       # ?? how is this different to @staticmethod ??
>>>>
>>>> Please explain the above.
>>>>
>>>> def some_instance_method (self, param1, param2):
>>>>       # can use self. here to reference the instance of the class
>>>>
>>>>
>>>> This is the normal method you get with Java without adding "static" to
>>>> the method signiture, so a standard instance method in Java would be the
>>>> equivalent of this?
>>>>
>>>>
>>>> Regards
>>>>
>>>>
>>>>
>>>> On 7/27/2011 11:42 PM, David Tseng wrote:
>>>>> For the purists out there, classes, functions, methods, procedures,
>>>>> etc are all sort of related.  You can think of a class as a function
>>>>> in python with some setup/teardown facilities, a closure, and a symbol
>>>>> table mapping it's instance variables/functions.  I don't think any
>>>>> language shows this better than javascript, but python comes pretty
>>>>> close.
>>>>>
>>>>> But, I think Jamal's right Jim, you should just dive in and see how
>>>>> things behave in practice and stop letting me and others confuse you
>>>>> :).
>>>>>
>>>>> On 7/27/11, Q<q@xxxxxxxxxxxxxxxxxx>   wrote:
>>>>>> Okay. First, everything is an object as you mentioned. This is
>>>>>> somewhat-important.
>>>>>> Now, functions vs. methods.
>>>>>> Generally in Python function means standalone callable. When I say
>>>>>> callable, I'm referring to an object which has a __call__ method.  So
>>>>>> when it comes down to it, functions are simply objects that define
>>>>>> __call__. But of course, we generally don't create these function
>>>>>> objects manually. That's just what happens when the interpreter reads
>> in
>>>>>> a def block.
>>>>>> So, a function is a regular callable that does not take an instance as
>>>>>> its first argument.
>>>>>> def test():
>>>>>>     print "hello, world!"
>>>>>>
>>>>>> While you could attach these types of functions to a class:
>>>>>> class Tester(object):
>>>>>>     pass
>>>>>>
>>>>>> Tester.test = test
>>>>>>
>>>>>> note what happens when you instantiate that class and try to use them:
>>>>>> t=Tester()
>>>>>> t.test()
>>>>>> TypeError: test() takes no arguments (1 given)
>>>>>> Because Python tries to pass the class instance in as the first
>> argument
>>>>>> to that function, and it takes none.
>>>>>> Now, there's absolutely no reason you couldn't do something like:
>>>>>> def other_test(self):
>>>>>>     print "Hi there!"
>>>>>>
>>>>>> and attach other_test to Tester.
>>>>>> And this would actually work just fine. It wouldn't be a true method
>>>>>> object, which has a couple of other attributes on it (try dir on a
>>>>>> function object and a method object for comparison)
>>>>>> Now, you mentioned static methods. How we create these is with the
>>>>>> staticmethod decorator.
>>>>>> Observe:
>>>>>>
>>>>>> class SomeClassWithStaticMethods(object):
>>>>>>
>>>>>>     @staticmethod
>>>>>>     def something_inside_the_class_namespace():
>>>>>>      return "I was called!"
>>>>>>
>>>>>> You can call this static method on any class object or instance. So
> you
>>>>>> could go
>>>>>>
>>>>>> SomeClassWithStaticMethods.something_inside_the_class_namespace()
>>>>>> or
>>>>>> c = SomeClassWithStaticMethods()
>>>>>> c.something_inside_the_class_namespace()
>>>>>>
>>>>>> but this is rarely-needed, generally better is putting a regular
>>>>>> function inside the class's module. This would only be required if you
>>>>>> explicitly want to have the function inside the class namespace, I.E.
> a
>>>>>> module with several unrelated classes.
>>>>>> Then, we have class methods, marked with the @classmethod decorator.
>>>>>> These are extremely-useful. They operate on class objects instead of
>>>>>> instance objects.
>>>>>>
>>>>>> class Something(object):
>>>>>>
>>>>>>     @classmethod
>>>>>>     def do_funky_things_to_the_class(cls):
>>>>>>      #You could do all kinds of hackery in here on the class object
>>> before
>>>>>> its already instantiated or whatever. cls contains the class object,
>> and
>>>>>> it's conventional to use cls in this case where self is for instance
>>>>>> methods.
>>>>>>      cls.some_attribute = 1 #all instances of this class will have
>>>>>> some_attribute set to 1 if you call this
>>>>>>
>>>>>> I hope this untangles things a little. If you don't understand
> anything
>>>>>> feel free to ask, but do do a lot of exploration with dir. also check
>>>>>> out the inspect module to let you poke around at the internals and see
>>>>>> what's going on a bit under the covers.
>>>>>> And if I'm mistaken about anything here, someone on list please-do
>>>>>> correct me as this is all stuff I've derived from usage.
>>>>>>
>>>>>>         Q
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On 7/27/2011 4:07 PM, Jamal Mazrui wrote:
>>>>>>> Yes, I think a function at the module level in Python is like a
> static
>>>>>>> method of that module.  The module, moreover, is like a singleton
>>>> object.
>>>>>>> Although these nuances can be interesting to discuss, let me
> encourage
>>>>>>> folks not to get hung up on terminology, thinking that one cannot
> code
>>>>>>> productively until certain theory or terminology is mastered.  I say
>>>>>>> try to understand as much theory as one can at the time, but then set
>>>>>>> aside a solid grasp of some aspects for now if they seems elusive.
>>>>>>>
>>>>>>> I think that learning is usually best achieved through an iterative
>>>>>>> process that involves both learning and applying ideas.  If one
>>>>>>> postpones actual application, there is only so far that one's
>>>>>>> understanding can go.  On the other hand, after experiencing the
>>>>>>> results of applied understanding, one can try to learn more, apply it
>>>>>>> in code, debug, regroup, etc.
>>>>>>>
>>>>>>> Jamal
>>>>>>>
>>>>>>> On 7/27/2011 3:45 PM, Homme, James wrote:
>>>>>>>> Hi,
>>>>>>>> Forgot to copy the list. This sounds like static methods in other
>>>>>>>> languages. Is that anywhere in the universe?
>>>>>>>>
>>>>>>>> Jim
>>>>>>>>
>>>>>>>> -----Original Message-----
>>>>>>>> From: David Tseng [mailto:davidct1209@xxxxxxxxx]
>>>>>>>> Sent: Wednesday, July 27, 2011 3:40 PM
>>>>>>>> To: programmingblind@xxxxxxxxxxxxx
>>>>>>>> Cc: Homme, James
>>>>>>>> Subject: Re: Python, Possibly OO, Terminology Question
>>>>>>>>
>>>>>>>> With respect to python's innate "object orientedness" where
>>>>>>>> everything's an object, you can think of functions and methods as
>>>>>>>> binding or associated with other objects.  A function or method
>> that's
>>>>>>>> "associated" with a class object, takes the class object as its
> first
>>>>>>>> parameter as you stated.  However, you can just as easily bind a
>>>>>>>> function or method to a class without that first "self" parameter.
>>>>>>>> The distinction lies in what the function or method is bound to.  In
>>>>>>>> the former, the function/method binds to an instance of that class
>>>>>>>> while the latter binds to the class itself.
>>>>>>>>
>>>>>>>> For example,
>>>>>>>> class foo:
>>>>>>>>      def instance(self):
>>>>>>>>        pass
>>>>>>>>
>>>>>>>>      def non_instance():
>>>>>>>>        pass
>>>>>>>>
>>>>>>>> I'd encourage you to not take any of our words for it and try it out
>>>>>>>> yourself.  Try typing the follwing into an interpreter.
>>>>>>>>>>> foo.non_instance
>>>>>>>>>>> foo
>>>>>>>>>>> foo.instance
>>>>>>>>>>> f = foo()
>>>>>>>>>>> f.non_instance
>>>>>>>>>>> f.instance
>>>>>>>>
>>>>>>>> On 7/27/11, Jamal Mazrui<empower@xxxxxxxxx>    wrote:
>>>>>>>>> I think the terms function, method, procedure, subroutine, or code
>>>>>>>>> block
>>>>>>>>> are generally synonymous.  They refer to a programming construct
>> that
>>>>>>>>> receives 0 or more parameters, executes code with those parameters
>> as
>>>>>>>>> data, and then returns 0 or more result values.
>>>>>>>>>
>>>>>>>>> A particular term may be used to emphasize an aspect of the context
>>>>>>>>> under discussion.  For example, a method implies being an aspect of
>>> an
>>>>>>>>> object.  A subroutine implies that there is no meaningful return
>>>> value.
>>>>>>>>>      A code block implies an in-line definition with access to
>>>>>>>>> surrounding
>>>>>>>>> variables.
>>>>>>>>>
>>>>>>>>> In general, however, I think there are not fine distinctions among
>>>>>>>>> these
>>>>>>>>> terms.
>>>>>>>>>
>>>>>>>>> Jamal
>>>>>>>>>
>>>>>>>>> On 7/27/2011 11:14 AM, Homme, James wrote:
>>>>>>>>>> Hi,
>>>>>>>>>>
>>>>>>>>>> I'm right at the point where I'm concerned about learning this the
>>>>>>>>>> wrong
>>>>>>>>>> way, so I'm asking now before it's cemented into my head. Is it
>>>>>>>>>> appropriate to use the term function and the term method
>>>>>>>>>> interchangeably? If so, why? If not, why not? I realize that in
>>>>>>>>>> Python,
>>>>>>>>>> when you have methods in the definition of a class, they always
>> have
>>>>>>>>>> self as the first argument, so that helps you realize that you are
>>>>>>>>>> looking at a method. I also know that if you make a program that
>>>>>>>>>> has no
>>>>>>>>>> classes in it, that you can use functions, and they don't look
> like
>>>>>>>>>> they
>>>>>>>>>> are attached to a class, but one of the books I was looking at
> says
>>>>>>>>>> that
>>>>>>>>>> everything in Python is an object, even if the code doesn't look
>>> like
>>>>>>>>>> that, but I'm trying to avoid dragging that into this discussion
> to
>>>>>>>>>> possibly artificially keep concepts separate in order to learn
>> them.
>>>>>>>>>>
>>>>>>>>>> Thanks.
>>>>>>>>>>
>>>>>>>>>> Jim
>>>>>>>>>>
>>>>>>>>>> Jim Homme,
>>>>>>>>>>
>>>>>>>>>> Usability Services,
>>>>>>>>>>
>>>>>>>>>> Phone: 412-544-1810.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> This e-mail and any attachments to it are confidential and are
>>>>>>>>>> intended
>>>>>>>>>> solely for use of the individual or entity to whom they are
>>>> addressed.
>>>>>>>>>> If you have received this e-mail in error, please notify the
> sender
>>>>>>>>>> immediately and then delete it. If you are not the intended
>>>> recipient,
>>>>>>>>>> you must not keep, use, disclose, copy or distribute this e-mail
>>>>>>>>>> without
>>>>>>>>>> the author's prior permission. The views expressed in this e-mail
>>>>>>>>>> message do not necessarily represent the views of Highmark Inc.,
>> its
>>>>>>>>>> subsidiaries, or affiliates.
>>>>>>>>> __________
>>>>>>>>> View the list's information and change your settings at
>>>>>>>>> //www.freelists.org/list/programmingblind
>>>>>>>>>
>>>>>>>>>
>>>>>>>> __________
>>>>>>>> View the list's information and change your settings at
>>>>>>>> //www.freelists.org/list/programmingblind
>>>>>>>>
>>>>>>>>
>>>>>>> __________
>>>>>>> View the list's information and change your settings at
>>>>>>> //www.freelists.org/list/programmingblind
>>>>>>>
>>>>>> __________
>>>>>> View the list's information and change your settings at
>>>>>> //www.freelists.org/list/programmingblind
>>>>>>
>>>>>>
>>>>> __________
>>>>> View the list's information and change your settings at
>>>>> //www.freelists.org/list/programmingblind
>>>>>
>>>
>>> --
>>> Kerneels Roos
>>> Cell: +27 (0)82 309 1998
>>> Skype: cornelis.roos
>>>
>>> __________
>>> View the list's information and change your settings at
>>> //www.freelists.org/list/programmingblind
>>>
>>> __________
>>> View the list's information and change your settings at
>>> //www.freelists.org/list/programmingblind
>>>
>>> __________
>>> View the list's information and change your settings at
>>> //www.freelists.org/list/programmingblind
>>>
>>> __________
>>> View the list's information and change your settings at
>>> //www.freelists.org/list/programmingblind
>>>
>>>
>> __________
>> View the list's information and change your settings at
>> //www.freelists.org/list/programmingblind
>>
>> __________
>> View the list's information and change your settings at
>> //www.freelists.org/list/programmingblind
>>
>>
> __________
> View the list's information and change your settings at
> //www.freelists.org/list/programmingblind
>
> __________
> View the list's information and change your settings at
> //www.freelists.org/list/programmingblind
>
>
__________
View the list's information and change your settings at 
//www.freelists.org/list/programmingblind

Other related posts:

  1. Home
  2. programmingblind
  3. Archive
  4. 07-2011