From: Jamis Buck <jamis@37signals.com>
Date: 2005-12-21T04:37:25+09:00
Subject: Re: Bruce Eckel wouldn't know why to switch from Python to Ruby

Excellent comparison, Lennon. Thanks for taking the time to post this.

- Jamis

On Dec 20, 2005, at 12:17 PM, rcoder wrote:

> Eckel's article is getting pretty long in the tooth at this point -- I
> remember reading it back when I was a Python user several years ago,
> and it actually delayed my swith to Ruby for a few months, at least. I
> probably don't qualify as a Python expert, but after being exposed to
> both for non-trivial projects, there are definitely some differences
> that make me prefer Ruby.
>
> First, because all object "slots" in Python are public, (stupid
> conventions like underscore prefixes aside) you see a lot of code like
> this:
>
> obj.setFoo("bar")
>
> This is because 'obj.foo = "bar"' is a direct assignment, with no
> method call involved. Since that's an encapsulation no-no, you get a
> bunch of long-winded setFoo and getFoo methods all over the place,
> which gives me nasty flashbacks to my days writing Java code. (Note:
> this is probably getting better now with the standard decorator syntax
> making automatic slot wrapper code generator more acceptable in the
> Python world.)
>
> Second, the crippled 'lambda' form (you can't include multiple
> statements, since Python imposes its fugly statement/expression
> separation) means you either a) give up on some very elegant potential
> uses of first-order functions, or b) pollute your namespace with a
> bunch of throw-away definitions that should be anonymous. Blocks and
> proc/lamba objects feel more expressive, at the cost of having to use
> the #call or #[] methods to actually invoke them.
>
> Also, while I'm less than proud to admit it, a few of the "Perl-isms"
> in Ruby, such as the =~ operator, simply seem more natural to me than
> their Python equivalents. I try to avoid using the special syntax and
> "magic" globals like $1, $2, et. al., but having spent so much time
> wearing a sysadmin hat, (and we all know that means reading and  
> hacking
> on Perl code) it's nice to just be able to toss out regexp-based
> one-liners when the urge/need arises.
>
> Finally, metaprogramming in Ruby has always been a more  
> straightforward
> and common practice than in Python. The combination of
> {class,module,instance}_eval, blocks, symbols (as a compact
> representation of method and attribute names), and import/subclass
> callbacks just makes more sense, IMHO, than metaclasses and multiple
> inheritance, which are more or less essential for idiomatic Python
> metaprogramming.
>
> I do miss a few things: most importantly, list comprehensions, and
> imported modules simply being another object/namespace to be used with
> normal dot-notation. Python has also had a clean syntax for keyword
> arguments in method calls for some time, and while I'm pretty
> comfortable with the implicit hash-conversion model, it still feels
> hacking compared to real kwargs.
>
> Regardless, I agree with the folks earlier in the thread who've said
> that you should pick the language that fits your brain better. For
> recovering Java programmers, that may well be Python, as the heavy use
> of inheritance and explicit setters and getters won't require any  
> major
> shift in design practices. On the other hand, if you're coming from
> Perl, or maybe even C++, where the style is more fluid, Ruby will
> probably feel more efficient, since you end up writing less  
> boilerplate
> code, and using a flatter class hierarchy.
>
> -Lennon
>
>