On Mon, 22 Jun 2009 00:14:50 -0400, Ben Charrow wrote:
> I have a question about the "Using Backslash to Continue Statements" in
> the howto "Idioms and Anti-Idioms in Python"
> (http://docs.python.org/howto/doanddont.html#using-backslash-to-
continue-statements)
>
>
> It says:
>
> "...if the code was:
>
> value = foo.bar()['first'][0]*baz.quux(1, 2)[5:9] \
> + calculate_number(10, 20)*forbulate(500, 360)
>
> then it would just be subtly wrong."
>
> What is subtly wrong about this piece of code? I can't see any bugs and
> can't think of subtle gotchas (e.g. the '\' is removed or the lines
> become separated, because in both cases an IndentationError would be
> raised).
As examples go, it's pretty lousy because you can't just copy and paste
it into an interpreter session and see for yourself. However, with some
helper objects:
def forbulate(*args):
return [1]
def calculate_number(*args):
return 2
class K: pass
foo = K()
foo.bar = lambda: {'first': [1, 2, 3]}
baz = K()
baz.quux = lambda *args: [3]*10
value = foo.bar()['first'][0]*baz.quux(1, 2)[5:9] \
+ calculate_number(10, 20)*forbulate(500, 360)
I can run the example. I confirm that it works without a space after the
line continuation character. Using Python 2.5, if I put a space after the
backslash I get
SyntaxError: unexpected character after line continuation character
followed by
IndentationError: unexpected indent
So I don't understand the claim that the code is "subtly wrong" either.
It looks to me like it's obviously wrong.
--
Steven
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