From: ptkwt@... (Phil Tomson)
Date: 2004-05-11T02:23:55+09:00
Subject: Re: in search of a compelling reason to use ruby....

In article <pan.2004.05.10.10.37.41.800624@sbcglobal.net>,
Ryan Paul  <segphault@sbcglobal.net> wrote:
>i'm a python programmer, and I have recently been hearing a lot about
>ruby. 

Good.

>A lot of python people seem to think ruby is in some way inferior,
>but I have yet to find any significant differences between the languages.
>The only differences I have found so far have been superficial syntactic
>things. The only real significant difference I have detected, is the
>absence of a module system in ruby.

??  absence of a module system in ruby?  What do you mean by that?  We've 
got modules.

>
>I would like to be able to make an objective and educated comparison. Ruby
>seems to have a relatively small, but intensely devoted following.
>Software that inspires such fervent support from a small community usually
>possesses tremendous power that most people are just too dense to discern
>(eg: ocaml, and BeOS). Consequently, I figured it would be worth my time
>to find out what it is that the fanatics find appealing.
>
>I am looking for:
>    - examples of tangible features that ruby has, which python doesnt.

Continuations, blocks.

>    - examples of scenarios where some facet of, or property specific to
>    ruby contributed to the simplification or improvement of a programming
>    project.

Here's one: Ruby's code blocks.  Deceptively simple, but very powerful in 
practice.  They allow you to easily create domain specific languages very 
easily in Ruby.

Quick example:  I'm taking a Quantum Computing class.  The prof is looking 
for a language for designing quantum circuits.  I signed up for the 
project and createed a 'language' I call QDL (Quantum Design Language), 
but it's reeally just plain Ruby under the covers - no parser needs be 
created.

Here's an example of QDL:

  circuit = QCircuit {
    QBits = 4
    l0 = QLayer {
      feynmann(0,3)
      feynmann(1,2)
    }
    l1 = QLayer {
      toffoli(2,3,0)
    }
  }

Basically this describes the structure of a simple quantum circuit with 
two layers and 3 gates.  It can be simulated.  I can now have my 
classmates write QDL without having to know anything about Ruby at all.   
Of course, if they're willing to learn a little Ruby it becomes much more 
powerful since they can access all of Ruby from QDL.

The magic here is Ruby's code blocks (the code between '{' and '}').  They 
can be passed around and 'called' or 'yield'ed to.  I suspect it would be 
very difficult to implement a QDL-like language in Python because Python 
doesn't have code blocks like this (you would have to create a parser).

(BTW: QDL is implemented in about 400 line of Ruby, that includes all the 
additional matrix operations (Kronecker product) and some simple error 
checking).

>    - facets of the language which may not necessarily be useful, but are
>    notably creative/innovative.
>



>Additionally, I realize that there is more to a language than its syntax
>and functionality. As a result, I am also interested in hearing about
>facets of the ruby community and ruby ideology, and anything else that
>ruby programmers feel contribute to their affinity for the language. 
>
>I have a feeling that most of the things that make ruby worth using can
>also be found in python. From the perspective a python programmer who has
>taken only a precursory glance at ruby, it looks like ruby suggests a
>functional style, while python suggests an imperative style. It also looks
>like ruby may be better suited for quick shell scripts, whereas python is
>better suited for bigger programs. I realize that I probably suffer from
>misconceptions, and i'm looking forward to having them corrected.

You can use Ruby for large projects as well.  There are rumors of 20,000 
to 30,000 line Ruby programs here.  Personally, I don't think I've written 
anything that was more than ~5000 lines of Ruby - of course, in my 
experience, 5K lines of Ruby packs about the same functionality as 
20K to 25K lines of C++ code.

>
>I sincerely hope nobody finds any of my comments offensive, I dont mean
>them as criticisms of ruby. I intentionally withhold criticisms until I am
>better versed in the benefits!


Mostly you need to try using Ruby on a small test project.  Actually using 
the language will give you a better feel for it than us telling you about 
it.

Phil