Re: style query: function attributes for return codes?

[Steven Bethard]

george young wrote:
[python 2.3.3, x86 linux]
I recently found myself writing something like:
def get_connection():
    if tcp_conn():
        if server_allows_conn():
            return 'good_conn'
        else:
            return 'bad_auth'
    else:
        return 'no_server'
cn = get_connection()
if cn == 'good_con': ...
This is obviously just evil, since a misspelling in the string
return is treacherous.  I'm considering function attributes:
def get_connection():
    if tcp_conn():
        if server_allows_conn():
            return get_connection.GOOD
        else:
            return get_connection.BAD_AUTH
    else:
        return get_connection.NO_SERVER
get_connection.GOOD = 1
get_connection.BAD_AUTH = 2
get_connection.NO_SERVER = 3
If I put this function in it's own module, the solution is obvious:
GOOD_CONN = 1
def get_connection():
    ...
        return GOOD_CONN   

But if this is a small utility function that belongs inside a
larger module/class, I would like to have it's return values
closely associated with the function, not just another value in
the parent class.
Sorry, I also meant to add that the other obvious way of dealing with 
this kind of thing is to make the results keyword parameters:

def get_connection(GOOD=1, BAD_AUTH=2, NO_SERVER=3):
    if tcp_conn():
        if server_allows_conn():
            return GOOD
        else:
            return BAD_AUTH
    else:
        return NO_SERVER
This has the benefit that if your user wants different return values 
they can specify them, but the disadvantage that someone improperly 
calling the function with more than 0 parameters will get, instead of an 
error message, a strange return value.

Steve
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