En Mon, 06 Jul 2009 03:33:36 -0300, Gary Herron
<gher...@islandtraining.com> escribió:
Gabriel Genellina wrote:
En Mon, 06 Jul 2009 00:28:43 -0300, Steven D'Aprano
<st...@remove-this-cybersource.com.au> escribió:
On Mon, 06 Jul 2009 14:32:46 +1200, Lawrence D'Oliveiro wrote:
I wonder how many people have been tripped up by the fact that
++n
and
--n
fail silently for numeric-valued n.
What do you mean, "fail silently"? They do exactly what you should
expect:
++5 # positive of a positive number is positive
I'm not sure what "bug" you're seeing. Perhaps it's your expectations
that are buggy, not Python.
Well, those expectations are taken seriously when new features are
introduced into the language - and sometimes the feature is dismissed
just because it would be confusing for some.
If a += 1 works, expecting ++a to have the same meaning is very
reasonable (for those coming from languages with a ++ operator, like C
or Java) - more when ++a is a perfectly valid expression.
If this issue isn't listed under the various "Python gotchas" articles,
it should...
Well sure, it's not unreasonable to expect ++n and --n to behave as in
other languages, and since they don't, perhaps they should be listed as
a "Python gotcha". But even so, it's quite arrogant of the OP to flaunt
his ignorance of the language by claiming this is a bug and a failure.
It shouldn't have been all that hard for him to figure out what was
really happening.
That depends on what you call a "bug". In his classical book "The art of
software testing", Myers says that a program has a bug when it doesn't
perform as the user expects reasonably it to do (not an exact quote, I
don't have the book at hand). That's a lot broader than developers like to
accept.
In this case, a note in the documentation warning about the potential
confusion would be fine.
--
Gabriel Genellina
--
http://mail.python.org/mailman/listinfo/python-list
