On 22/08/12 20:03, Evan Driscoll wrote:
On 08/22/2012 12:46 PM, lipska the kat wrote:
If you can show me a 'type' that cannot be assigned to
a
in the same scope then I would be most interested to know, I haven't
found one yet.
[snip]
Second, this concept isn't *so* unfamiliar to you. If I give you the
following Java code:
void foo(Object o) { ... }
and ask what type 'o' is, there are kind of two answers. The first is
that 'o' is an 'Object'. But you can't make an Object -- that's an
abstract class. (IIRC. If it's not then just bear with me; you get the
idea. :-)) So from a strictly static type-theory point of view, 'foo' is
unusable because it takes a type which you can never create. But of
course that's not the case, because in actual Java 'o' has some dynamic
type which is a subclass of 'Object'.
Well I think this is where I'm struggling a bit.
looking at this method declaration I can see that the method takes an
argument of type Object (and just FYI class Object is not abstract and
you can do Object o = new Object()) and does not return a value.
I know that for the lifetime of this JVM, whatever o turns out to be it
will always be an Object. I can't assign a primitive to o as ints chars
floats etc are certainly not Objects. There are certain invariants that
give me a warm and comfortable feeling inside.
compare this to a function declaration in Python
def foo(self):
... I can learn nothing about this function by looking at the first line
If I see
def foo(self, someVar=1):
I can determine that foo takes an argument that, at some time or other
is or has been a number of some description but I can't rely on it and I
have no idea what is returned and that's where I think I'm having trouble.
But I will get over it and I will learn the language and I may look back
on these exchanges and say ... I was wrong, this is so much better that
what I was used to, or maybe I won't. I'll let you know
Thank you for your calm and reasoned response.
Disclaimer:
None of my comments above should be construed as criticisms
they are just observations.
lipska
--
Lipska the Kat©: Troll hunter, sandbox destroyer
and farscape dreamer of Aeryn Sun
--
http://mail.python.org/mailman/listinfo/python-list
