On Nov 18, 10:22 am, Steve Holden <[EMAIL PROTECTED]> wrote in thread "Python-URL! weekly Python news and links (Nov 17)": > [EMAIL PROTECTED] wrote: > [...] >> One of the reasons I would like to formulate a good >> model of an object's value and type is so that I could >> try to offer something better. Responses like yours >> are significantly demotivating. > > And yet you argue when people try to explain to you that objects don't > *have* values, objects *are* values. Objects have attributes, which are > references to other values. One of an object's attributes is its type.
I am sorry for arguing with you. I hear you and others saying that the value (in the english language sense of value) of an object *is* the object. But before I address that, I am a little confused by what you wrote above. Quoting the PLR again, "Every object has an identity, a type and a value." I presumed "value" to include attributes. Are you saying the correct statement in the PLR should have been, "Every object has an identity, attributes, and a value"? The text below refers to identity, type and value per the PLR, but you can substitute "attributes" for type without affecting the logic. Here is why I am having trouble accepting the explanations you and others have kindly offered me. If values are objects then the words "object" and "value" are synonymous, yes? Fine, I can see that could be a desirable thing. Value is more natural than object for people coming to Python, for example. But if you use the word value synonymously with object, then the PLR statement that "an object has identity, type, and value" is the same as "an object has identity, type, and itself". We know the object is itself!　That's tautological. So what is the point of using the term value in the definition of "object"? You can just say "an object has identity and type, and we will also use the word value as a synonmym for object." Other than cosmetics, the word "value" serves no purpose and we can replace it with "object" wherever we use it. E.g. "the result of evaluating an expression is a value.", "the result of evaluating an expression is an object". If value is the same as object, then Python objects have only identity and type. But you know that's not true. The types of int(2) and int(3) are the same. Is the difference in behavior of the two objects due to their different identities?! Python knows the object at 0x260FF44 is a "2" object, and the object at 0x260FD60 is a "3" solely by virtue of their addresses? Of course not. I hope you see why I find the "value is object" to be an unacceptable explanation of Python objects. > You seem to be hunting for the ineffable > "primitive value" that has no other attributes. > Such a thing doesn't exist. Sorry to argue again, but I explained (in a previous post) why I believe such a thing does exist. Specifically, it is necessary to explain the difference between the objects int(2) and int(3). Perhaps if you tell me exactly what fault you find with that previous explanation (in light of my problem with "values are objects" above), I could reevaluate my understanding. -- http://mail.python.org/mailman/listinfo/python-list
