FWIW I always liked
Dart's/Ruby's/Crystal's/(Coffee|Moon)Script's/WhateverElse's style:
class Cls {
Cls(this.a); // IT'S MAGIC
}
but the Python equivalent is admittedly weirder:
def ___init__(self, self.attr):
partly because, it'd have to work on pretty much any other variable name,
yet there's no other real use case outside of methods.
--
Ryan (ライアン)
Yoko Shimomura > ryo (supercell/EGOIST) > Hiroyuki Sawano >> everyone else
http://refi64.com
On Apr 24, 2017 8:08 PM, "Erik" <pyt...@lucidity.plus.com> wrote:
> Hi. I suspect that this may have been discussed to death at some point in
> the past, but I've done some searching and I didn't come up with much.
> Apologies if I'm rehashing an old argument ;)
>
> I often find myself writing __init__ methods of the form:
>
> def __init__(self, foo, bar, baz, spam, ham):
> self.foo = foo
> self.bar = bar
> self.baz = baz
> self.spam = spam
> self.ham = ham
>
> This seems a little wordy and uses a lot of vertical space on the screen.
> Occasionally, I have considered something like:
>
> def __init__(self, foo, bar, baz, spam, ham):
> self.foo, self.bar, self.baz, self.spam, self.ham = \
> foo, bar, baz, spam, ham
>
> ... just to make it a bit more compact - though in practice, I'd probably
> not do that with a list quite that long ... two or three items at most:
>
> def __init__(self, foo, bar, baz):
> self.foo, self.bar, self.baz = foo, bar, baz
>
> When I do that I'm torn because I know it has a runtime impact to create
> and unpack the implicit tuples and I'm also introducing a style asymmetry
> in my code just because of the number of parameters a method happens to
> have.
>
> So why not have an augmented assignment operator for object attributes? It
> addresses one of the same broad issues that the other augmented assignment
> operators were introduced for (that of repeatedly spelling names).
>
> The suggestion therefore is:
>
> def __init__(self, foo, bar, baz, spam, ham):
> self .= foo, bar, baz, spam, ham
>
> This is purely syntactic sugar for the original example:
>
> def __init__(self, foo, bar, baz, spam, ham):
> self.foo = foo
> self.bar = bar
> self.baz = baz
> self.spam = spam
> self.ham = ham
>
> ... so if any of the attributes have setters, then they are called as
> usual. It's purely a syntactic shorthand. Any token which is not suitable
> on the RHS of the dot in a standard "obj.attr =" assignment is a syntax
> error (no "self .= 1").
>
> The comma-separators in the example are not creating a tuple object, they
> would work at the same level in the parser as the import statement's
> comma-separated lists - in the same way that "from pkg import a, b, c" is
> the same as saying:
>
> import pkg
> a = pkg.a
> b = pkg.b
> c = pkg.c
>
> ... "self .= a, b, c" is the same as writing:
>
> self.a = a
> self.b = b
> self.c = c
>
> E.
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