Why do only callable objects get a __name__?

[Steven D'Aprano]

On Mon, 18 Nov 2013 13:02:26 -0800, John Ladasky wrote:

> I am implementing a state machine.  The outputs of the various states in
> the machine have variable contents.  I started by making dictionaries
> for each state output, but I soon tired of the bracket-and-quote-mark
> syntax for referring to the contents of these state output dictionaries.
>  That's why I am switching to named tuples.  It doesn't affect the
> __name__ issue, since dictionaries also cannot be called.
> 
> I want to capture the names of the executed states in a record of the
> state machine's history.  This information is already encoded in the
> namedtuple's type.


I find this rather confusing. Does every state have it's own unique 
namedtuple class?


state1 = namedtuple("State1", ("x", "y"))(1, 2)
state2 = namedtuple("State2", ("x", "y"))(5, 7)
state3 = namedtuple("State3", ("x", "y"))(0, 2)
[...]

Seems excessive -- you're defining many classes, each one of which has 
only a single instance. I'd be more inclined to just use a class object 
directly, with a little helper function to handle the tedious bits:

def state(name, x, y):
    class Inner(object):
        pass
    Inner.x = x
    Inner.y = y
    Inner.__name__ = Inner.name = name
    return Inner


And in use:

py> state1 = state('state1', 100, 101)
py> state1
<class '__main__.state1'>
py> state1.name
'state1'
py> state1.x
100


But I don't really understand how you are using these state objects, so 
I'm not sure if this is appropriate or not.


-- 
Steven