... I need a better email client. *double-checks I got everything right
this time...*
On 23/01/17 11:30 AM, Soni L. wrote:
Sorry, I replied to this wrong. Not used to this mailing list.
On 23/01/17 11:28 AM, Soni L. wrote:
On 23/01/17 11:18 AM, M.-A. Lemburg wrote:
On 23.01.2017 14:05, Soni L. wrote:
On 23/01/17 09:45 AM, Serhiy Storchaka wrote:
On 23.01.17 01:30, Soni L. wrote:
On 22/01/17 08:54 PM, Serhiy Storchaka wrote:
On 23.01.17 00:45, Soni L. wrote:
I've been thinking of an Immutable Builder pattern and an operator
to go
with it. Since the builder would be immutable, this wouldn't work:
long_name = mkbuilder()
long_name.seta(a)
long_name.setb(b)
y = long_name.build()
I think the more pythonic way is:
y = build(a=a, b=b)
A Builder pattern is less used in Python due to the support of
keyword
arguments.
I guess you could do something like this, for an IRC bot builder:
fnircbotbuilder = mkircbotbuilder(network="irc.freenode.net",
port=6697,
ssl=true)
mainbot = mkircbotbuilder(parent=fnircbotbuilder, # ???
channels=["#bots"]).build()
fndccbotbuilder = mkircbotbuilder(parent=fnircbotbuilder, dcc=true,
channeldcc=true)
dccbot = mkircbotbuilder(parent=fndccbotbuilder,
channels=["#ctcp-s"]).build()
otherircbotbuilder = mkircbotbuilder(parent=fndccbotbuilder,
network="irc.subluminal.net") # because we want this whole network
otherbot = mkircbotbuilder(parent=otherircbotbuilder,
channels=["#programming"]).build() # to use DCC and channel DCC
But this would be cleaner:
botbuilder =
mkircbotbuilder().network("irc.freenode.net").port(6697).ssl(true)
mainbot = botbuilder.channels(["#bots"]).build()
botbuilder .= dcc(true).channeldcc(true)
dccbot = botbuilder.channels(["#ctcp-s"]).build()
botbuilder .= network("irc.subluminal.net")
otherbot = botbuilder.channels(["#programming"]).build()
In Python you can save common options in a dict and pass them as
var-keyword argument. Or use functools.partial. In any case you don't
need a builder class with the build method and a number of
configuring
methods. It can be just a function with optional keyword parameters.
A Builder pattern is often used in languages that don't support
passing arguments by keyword and partial functions. Python rarely
needs the purposed class implementing a Builder pattern. Actually a
Builder pattern is built-in in the language as a part of syntax.
Yeah but the dotequals operator has many other benefits:
long_name .= __call__ # cast to callable
long_name .= wrapped # unwrap
etc
And it also looks neat.
I don't see this an being a particular intuitive way of writing
such rather uncommon constructs.
The syntax is not clear (what if you have an expression on the RHS)
and it doesn't save you much in writing (if long_name is too long
simply rebind it under a shorter name for the purpose of the code
block).
It's literally sugar for repeating the name and moving the dot to the
right. I think it's clearer than most other compound operators in
that it doesn't affect precedence rules.
`x += y`, for any code `y`, is equivalent to `x = x + (y)`, not `x =
x + y`.
`x .= y`, for any code `y`, is equivalent to `x = x . y`, not `x = x
. (y)`.
Also note that rebinding different objects to the same name
in the same block is often poor style and can easily lead to
hard to track bugs.
Rebinding different objects to the same name in rapid succession is
fine.
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