From: Greg McIntyre <greg@...>
Date: 2003-03-21T10:00:03+09:00
Subject: Re: Strong advantages over Python

Good list. Amalgamated with http://www.ruby-lang.org/en/whats.html, it
should make a concise enough list of advantages.

Travis Whitton <whitton@atlantic.net> wrote:
> o Super easy to extend with C modules

Yup. Although with SWIG...


> o The power of mixing in Enumerable
> o Simplicity of mixins vs multiple inheritance

Debatable but okay. I would think about this point differently. Ruby has
a simple object model - objects are a bunch of variables and methods,
and Ruby gives you the means to add/subtract/edit them with a lot of
power.


> o A builtin class library small enough to memorize but powerful enough
>   to do basically anything you want

This is something I love about Ruby over Python. I hate the Python
library reference -- it's *so* hard to find what you want to do using
it. Whereas on the off chance you actually need to look something up
while programming Ruby (as most things work by Ruby reading your mind),
you generally know exactly where to look for it.

So yes, that's an important practical difference, IMO.


> o Total syntactic consistency(everything is an object)
>   5.times {|num| ...}
>   "foo".reverse
> o Stronger typing(everything has a specific type)
>   1.type => Fixnum

Some examples of the benefits of pure OOP. I use "have a nice day".split
a fair bit, but Python can do that too so it makes it less enjoyable. ;)
['dir1', 'dir2', 'filename'].join(File::Separator) might be a better
example.

This also relates to the fact that you generally know where to look for
a particular method in Ruby. In Python, join is a function defined in
the string module. How I was supposed to know that without popping up
the huuuge index page of the library reference and searching for 'join',
I don't know.


> o Truly private data instead of name mangling

Yes! There can be some excellent examples of this too.


> o No equivalent of a do ... while statement

Ah! I didn't know that. How... Eiffelish.


> o self.myvar vs @myvar

Not necessarily an advantage...


> o No closures in Python?

Okay. I'm no Python expert, but...

Python 2.2 is a bit better. They're still not the same however. AFAIK
you use lambdas in Python to create closures (assigning the lambdas to
variables and calling them later on). But lambdas expect 'expressions'
not 'statements' meaning you can only do a very limited number of things
in your Python closure. Also, you cannot assign to a variable which is
in a closure's context but outside its direct scope (e.g. something
assigned just above a Ruby block). There are dirty tricks to get around
it but they're difficult and ugly. Hrm... there might be some other
differences too.

In Python you can assign function names to variables and then call them
through those variables, however AFAIK this relies on separate function
definitions and global variables in order to achieve the same level of
context manipulation possible with a Ruby block, so it certainly isn't
as clean and easy.

I'd appreciate it if the more Python-inclined could correct or confirm
all that.

-- 
Greg McIntyre
greg@puyo.cjb.net
http://puyo.cjb.net