improve this newbie code/nested functions in Python?

[Terry Reedy]

Esmail wrote:
> Hi,
> 
> I'm new to writing Python code. This is a simple client I wrote, it
> works, but I feel it doesn't look as clean as it could. Can anyone
> make suggestions how to streamline this code?
> 
> Also, I am using two nested functions, it seems that nested functions
> aren't used that much in Python - is that correct? And if so, how
> come?

What you wrote are two nested classes, not functions.  In my opinion, 
neither should be nested.  Nothing is gained and something is lost. 
Neither are used by client; indeed both use client.

Nested classes are rare because they have little use and are almost 
never necessary.

Nested functions are a different story.

I would rename '_parent' (misleading) as 'client' or 'user'.

Terry Jan Reedy


> ps: I realize there is minimal error checking/exception handling.
> 
> #!/usr/bin/env python
> 
> 
> import sys
> from socket import *
> from threading import Thread
> 
> 
> class Client(object):
>     def __init__(self, host="localhost", port=5555, name = "esmail"):
>         self._host = host
>         self._port = port
>         self._name = name
>         self._address=(self._host, self._port)
>         self._sock=socket(AF_INET, SOCK_STREAM)
>         self._sock.connect(self._address)
>         self._parent = self

Makes no sense in the code given.

>         self._keepGoing = True
> 
>     def info(self):
>         return self._host, self._port, self._name
> 
> 
> 
>     class Listener(Thread):
>        def __init__(self, parent, tname="listener"):
>            Thread.__init__(self,name = tname)
>            self._parent = parent
>            print self._parent._host
> 
>        def run(self):
> 
>            while self._parent._keepGoing:
>                m = self._parent._sock.recvfrom(1024)
>                print m[0]
> 
> 
> 
>     class Speaker(Thread):
>        def __init__(self, parent, tname = "speaker"):
>            Thread.__init__(self,name = tname)
>            self._parent = parent
>            self._parent._sock.send(self._parent._name + "\n")
> 
> 
>        def run(self):
> 
>            while(True):
>                m = raw_input("-> ")
>                if m == "bye":
>                    self._parent._sock.send(self._parent._name + " is
> signing off.\n")
>                    self._parent._sock.send("bye\n")
>                    self._parent._keepGoing = False
>                    break;
>                else:
>                    self._parent._sock.send(m + "\n")
> 
> 
> def main():
> 
>     if len(sys.argv) == 4:  # prog name + 3 args
>         host = sys.argv[1]
>         port = int(sys.argv[2])
>         name = sys.argv[3]
>         c = Client(host, port, name)
>     else:
>         c = Client()
> 
>     print "Client connecting to - host=%s  port=%d   name=%s" % c.info
> ()
> 
>     s = Client.Speaker(c)
>     s.start()
> 
>     l = Client.Listener(c)
>     l.start()
> 
> 
> main()
> --
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>