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On the future of Perl 5On the future of Perl 5Posted Dec 3, 2008 20:10 UTC (Wed) by niner (subscriber, #26151)In reply to: On the future of Perl 5 by sbergman27 Parent article: On the future of Perl 5
"Explicit" as in implicit type conversion? Just right now got bitten by that:
0: looks like a zero, tastes like a zero, but somewhere along the line got converted to a string and therefore it's suddenly True, not False.
Another very nice argument: "Perl looks confusing to outsiders coming from other
Whoops! What happened here? "++i" is obviously legal Python code with just one
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On the future of Perl 5 Posted Dec 3, 2008 20:52 UTC (Wed) by sbergman27 (guest, #10767) [Link]
"""
"Explicit" as in implicit type conversion? Just right now got bitten by that: 0: looks like a zero, tastes like a zero, but somewhere along the line got converted to a string and therefore it's suddenly True, not False. """
Please be more specific. Where are you saying that Python does implicit type conversion? Python types dynamically, but strongly. Sure you're not thinking of Javascript, where "2" + 2 = "22"?
On the future of Perl 5 Posted Dec 3, 2008 21:36 UTC (Wed) by sbergman27 (guest, #10767) [Link]
Oh, forgot to mention that "+" is, of course, the unary plus operator:
---
> -x
> ++x
> --x
> +++x
> ---x
How would you handle that differently, keeping in mind that not stepping on Perl's rather bizarre syntax is not top priority?
And just to make a point:
---
In perl that would have silently become a numeric 0. Oops.
On the future of Perl 5 Posted Dec 3, 2008 21:44 UTC (Wed) by dlang (✭ supporter ✭, #313) [Link]
++ can be a different operation than +
just like many languages use * for multiplication and ** for exponents
many languages also support the concept of i++ and ++i as a command to add 1 to i. in python it's valid syntax, but produced unexpected (to many programmers) results.
On the future of Perl 5 Posted Dec 3, 2008 22:05 UTC (Wed) by sbergman27 (guest, #10767) [Link]
Of course. I doubt there is a language that does not have a pothole or two to fall into for programmers coming from other languages. Niner's "++i" selection was a bit cherry-picked in my opinion. I wonder how Perl's "potholes per mile" figure compares to Python's? I've programmed in both, neither having been my first language, and I have a strong opinion on that matter.
On the future of Perl 5 Posted Dec 3, 2008 22:41 UTC (Wed) by dlang (✭ supporter ✭, #313) [Link]
in my experiance with perl, if you try a construct from just about any language it will probably work, if it doesn't it will give you a syntax error (whitespace being significant is an exception)
this is both a blessing and a curse.
it's great for writing programs (especially when they really are one use), but it means that if you are looking at programs that other people wrote and have not done any thinking about code style you can run into constructs from many different languages.
On the future of Perl 5 Posted Dec 7, 2008 2:05 UTC (Sun) by madscientist (subscriber, #16861) [Link]
> And just to make a point:
> > --- >> x = "0" >> y = -x > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > TypeError: bad operand type for unary -: 'str' > --- > > In perl that would have silently become a numeric 0. Oops.
I don't get the point you're trying to make. When or why would Perls' behavior be an "oops"? Or put another way, what problem would this cause in the code?
On the future of Perl 5 Posted Dec 4, 2008 14:30 UTC (Thu) by pboddie (subscriber, #50784) [Link] "Explicit" as in implicit type conversion? There are hardly any implicit conversions in Python, and certainly none between strings and numbers. Just right now got bitten by that: My guess is that you used "print" or "str" to see the value, when you should have looked at the representation using "repr". Just evaluating the thing which provided the value in the interpreter would give you the representation. Whoops! What happened here? "++i" is obviously legal Python code with just one unexpected effect: nothing. It just does nothing. Endless loop, here we come. "++" is you using the unary plus operator twice, not some operator that isn't in the language: obvious if you've read even a small amount of the documentation. There are a few things about Python which could be better, even in Python 3.0, but I don't think the improvements need to come from the language in this particular instance.
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