On 12/03/2016 11:51, Marko Rauhamaa wrote:
BartC <b...@freeuk.com>:
What's big deal with dynamism anyway? I could never understand
Python's obsession with it.
For me, 'dynamic' means that a variable has a dynamic type; that's
all. But you know at compile-time (or when looking at source code)
whether a name is a variable, or a function, class, module, named
constant and so on.
*I* am obsessed with dynamism. It means I don't have to declare object
data members but can write ad hoc:
def some_method(self):
self.update_state()
self.state_specific_info = "Kilroy was here"
The "state_specific_info" attribute didn't exist before I wished it into
existence. No bureaucracy, just add it where it belongs.
I was talking about 'top-level' names more than attributes (names that
follow a dot).
Ad-hoc attributes I don't have as much of a problem with, as they can be
handy. But predefined ones also have their points. (For one thing, I
know how to implement those efficiently.)
However, when you have a function call like this: M.F(), where M is an
imported module, then it is very unlikely that the functions in M are
going to be created, modified, deleted or replaced while the program
runs. [I mean, after the usual process of executing each 'def' statement.]
Why then should it have to suffer the same overheads as looking up
arbitrary attributes? And on every single call?
I also have a high level of method/attribute transparency. It doesn't
matter if I declare:
def this_or_that(self):
if self.that:
self.that()
else:
self.this()
[...]
self.that = True
or:
self.this_or_that = self.that
This example, I don't understand. Do you mean that when your write X.Y,
that Y can be an attribute of X one minute, and a method the next? (In
which case I wouldn't want to have to maintain your code!)
Somewhat related, every method is an automatic delegate. Defining
callbacks is a breeze:
def clickety_click(self, x, y):
[...]
[...]
window.register_mouse_click_callback(self.clickety_click)
I don't follow this either. What's the advantage of dynamism here?
That optimization wouldn't have any effect on any of my code.
More generally, every method call in Python is such an elaborate
exercise that dabbling with character constants is going to be a drop in
the ocean.
When you dabble with lots of little things, then they can add up. To the
point where an insignificant optimisation can become significant.
--
Bartc
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