Re: Article on Ruby in Software Development magazine

   JamesBritt wrote:
> Got back fro Seattle yesterday, picked up my mail from the post office today,
> and was pleased to see that the December issue of Software Development magazine
> has an article on Ruby by Rick Wayne.  A star rating is given as well; Ruby
> earned four out of a possible five stars, meaning it's "[g]reat. The product is
> near the top of its class and probably belongs in your shop."

Just wanted to say that the article is now online. You need to register 
before you can read it. So for those that don't want to, here's the txt:

A Joyful Gem

You may know a baker's dozen programming languages, but make room for 
one more: According to its inventor, Yukihiro Matsumoto, Ruby can put 
the fun back in your code.

By Rick Wayne

What, another language to learn? Why bone up on Ruby, when any 
programmer worth her debugger can name a dozen useful languages? Three 
answers: learning, fun and productivity. Listen to Yukihiro Matsumoto 
(a.k.a. "Matz"), Ruby's inventor: "To be honest, Ruby is not yet a 
'job-making language.' But learning new programming languages teaches 
you new ideas." He points out that Ruby teaches you dynamic 
object-oriented programming, scripting in a pure OO language, and, 
perhaps most importantly, the joy of programming. In our profession, new 
ideas are at a premium, as is joy預nd Matsumoto claims that Ruby can 
invigorate even the most jaded cube-dweller.

Joy ? Toy
But don't assume that joy equals toy羊eal engineers use Ruby for real 
projects, and their number is growing rapidly. Should you join them? It 
depends on what you do. Speed-crazed bit-bashers shoehorning MPEG codecs 
into 16K ROMs need not apply: High-level scripting languages remain 
slower and fatter than low-level compiled ones. And no one's likely to 
write an OS in Ruby anytime soon由uby itself, after all, is built on top 
of C. But for general-purpose work, the language is definitely worth a look.

For taxonomists, Ruby is a pure object-oriented interpreted scripting 
language with weak typing. It offers easy access to operating-system 
facilities, little to no boundary between compile time and runtime, and 
the Big Three of Objects: encapsulation, inheritance and polymorphism. 
"Pure" just means that all language elements are objects; object 
orientation is built in, rather than bolted on. Yet Ruby allows a 
procedural style suitable for quickly throwing together a one-off 
script, and in addition to the traditional interpreter, there's an 
interactive environment for incremental development.

Ruby effectively bridges the worlds of quickie scripting and real 
software engineering. Those "throwaway" programs have a habit of 
clinging stubbornly to life, evolving into major systems over time預nd a 
strange attractor called "Big Ball of Mud" ensnares many of them. Ruby 
proponents claim to usually avoid it. Why? Well, for one thing, it's 
simple to refactor and test Ruby classes. There's no intervening 
compilation, and weak typing lets you change a class's interface without 
compiler natterings. The interactive environment even lets you 
incrementally add or replace class members on-the-fly.

Ruby shamelessly borrows good ideas from other languages. As in 
Smalltalk, everything's an object, whose type is determined purely by 
the messages it responds to. From LISP comes the idea of mixins to 
extend classes. Perl fans will recognize the regular-expression support, 
right down to "$_" and its friends. (I said it was shameless.) Java 
wonks will be pleased to see garbage collection, as well as useful 
built-in class libraries. C hackers can dive under the hood and extend 
the language for low-level programming. And, of course, the general 
intent預 scripting language for OO development擁s certainly familiar to 
Python aficionados.

Traveling Light
But Ruby has a distinctive syntax and a "feel" all its own, carrying 
little syntactic baggage. The Principle of Least Surprise holds: Things 
just work the way you expect. Programmers who've switched say that they 
spend more time pleasing the customer, instead of the compiler. Dave 
Thomas, coauthor (with Andy Hunt) of The Pragmatic Programmer 
(Addison-Wesley, 1999) and Programming Ruby (Addison-Wesley, 2000), 
described a recent multiphase delivery project of eight weeks' duration 
that deployed 25,500 lines of Ruby source in roughly 300 classes預nd 
that was on time, with no bugs in production.

"This was a serious rush job," he states, "with an absolute deadline. I 
honestly couldn't have done it in any other language I know (and I know 
a few)."

My initial Ruby experience bears this out. Our group's C library for 
access to our home-brewed weather database comprises about 2,000 lines. 
Two hours after I opened my laptop, Programming Ruby and a text editor, 
I had 156 lines of Ruby that could read the format, retrieve data and 
write it to relational tables; with a little refactoring, I'm still 
using that code today.

Ruby's World
Let's take a look at some features and syntax examples that demonstrate 
what's different about Ruby.

Callbacks and coroutines crop up all over. In the Visitor design 
pattern, users of a collection can visit each item in turn, doing "X" 
with each. Event handlers use callbacks, too: "Do X whenever there's a 
mouse click on me." In C, you'd use function pointers; in Java, you'd 
use inner classes or design a pair of cooperating classes. Ruby 
implements callbacks with code blocks, pieces of code contained between 
curly braces or the keywords do and end. Code blocks can be passed to a 
method; inside the method, the yield keyword executes the code block as 
if it were inlined. If yield has parameters, these get passed to the block.

Doesn't sound like much? Wait till you see blocks in action. For 
example, to initialize, utilize and dispose of a resource, you might see 
Java boilerplate like:

File aFile = new File("input.txt");
  BufferedReader rdr =
   new BufferedReader(new FileReader(aFile));
  handleLines(aFile); // process all the lines
  aStream.close();

Ruby internalizes the boilerplate. Its File.open() method can accept a 
block of code. Deep down, open() yields to the block; after it runs, 
control passes back to open(), which closes the file.

Ignoring exception processing (which adds 4-5 lines to each example), 
the Ruby syntax is a one-liner:

File.open("input.txt") { |aFile| handleLines(aFile) }

Ruby also implements iterators with code blocks, which leads to a 
natural style that's brief and readable. Let's flesh out our example a 
bit, replacing handleLines with code that prints each line to standard 
output. We'll exploit Ruby's File.each_line() method to iterate over the 
file, and include exception processing, too. No loops, return values or 
end conditions:

begin
     File.open("input.txt") do |aFile|
        aFile.each_line {|aString| puts(aString)}
     end
  rescue SystemCallError
     handleException # defined elsewhere
  end

A world-beater? Probably not. Still, it's more straightforward than the 
13-line Java equivalent. I'm not just whaling on Java's class library, 
here; it's no coincidence that Ruby's File provides the useful open() 
method and the each_line() iterator. Rather, the availability of blocks 
makes it so simple to build iterators and suchlike that when you need 
them, you'll find them容ven in your own classes. In fact, you can 
exploit existing code in your classes, too, via Ruby's analogue to 
multiple inheritance. Although Ruby is a single-inheritance language, 
mixins can give a class behavior from more than just one ancestor.

For example, suppose you have a Programmer class that needs to support 
comparison operators based on average number of defects per line of code 
(for example, rick > finn). All that Programmer has to do is implement 
the comparison method <=> (returning -1, 0 or 1 for less than, equals or 
greater than), and you can mix in Ruby's Comparable module. Now your 
class suddenly sports the operators <, <=, ==, >= and >. If you have an 
aggregate class Team for groups of programmers and build an each method 
for visiting each in turn, you can mix in the Enumerable module-now Team 
magically has methods for searching and sorting. To find objects 
matching a pattern, use grep; find_all returns an array of objects 
matching a criterion (which you pass in via yet another block), sort 
returns an array of Programmer objects sorted on 
defects-per-line葉here's more, but you get the idea.

Duck Typing
If you were raised on strongly typed languages like Pascal, C or Java, 
you probably believe that I'm trying to pull a fast one. "Wait a minute, 
just how does Enumerable even know that Team has an each method?" Well, 
it doesn't until runtime; enter Duck Typing. (Dave Thomas: "If it looks 
like a duck and quacks like a duck ) In other words, an object's type 
depends only on the messages it responds to; the determination is made 
at runtime, when the method is called. If it exists, all goes 
swimmingly; if not, an exception is thrown.

It sounds dangerous to us strongly typed types: We're used to a Compiler 
Cop standing between anarchy and us. But in my experience, Duck Typing 
just works; perhaps since it's so painless to run bits of 
scripting-language code, the bugs tend to get worked out early.

You can also modify classes at runtime, enabling introspection and 
"metaprogramming." The latter involves first building infrastructure 
methods that modify classes; those can then assume much of the scut 
work. For example, to use a persistence engine, you might build a method 
addPersist("foo", Integer) that would add an integer member "foo" to the 
class and set up storage and accessor methods in a single stroke.

What's Not to Like?
Ruby's not entirely wart-free. Matz admits that "Ruby's local scoping 
rule is too complex." And, "Some class libraries are not consistent with 
others. This is because they're not designed by me. I wish I had enough 
time, power and knowledge to implement them all in a consistent manner." 
Some love the power of redefining classes at runtime; others think 
that's dangerous: "Three things are most perilous: Connectors that 
corrode/Unproven algorithms/And self-modifying code." (from Duane Elms' 
song; "Threes, rev. 1.1, The Programmer's Anthem," 1988)

Weasel No More
Should you learn Ruby? If you have only compiled languages in your 
toolbox, definitely yes耀cripting languages offer excellent bang for the 
buck. Ruby excels at "glue" code, pulling OS tools together with 
libraries from other languages. If you like Perl but would prefer 
cleaner object-orientation, Ruby is a shoo-in. If you're up-to-speed on 
Python, it's a harder question; I personally had an easier time learning 
Ruby, but at the end of the day, your productivity in each might not 
differ hugely.

Finally, don't think of time spent learning a language as time lost. 
Even if you go back to your standard, you'll be a better developer, 
aware of alternatives. That freshly aired mind will make you a clearer, 
more critical thinker預nd you'll spend less time debugging!

Efficient, Invisible Fun
The buzz on Ruby

"The most important concepts in Ruby can be written in the letters FUN 
and JOY. Programming is supposed to be fun, but for various reasons, we 
often forget that. Ruby helps you to remember programming joy again."

雄ukihiro Matsumoto, Ruby creator

"Ruby works because it allows me to write code in terms of my user's 
problems, rather than in terms of language technicalities. This match 
leads to great efficiencies: When the client wants a change, the 
language they use to describe it is very similar to the code needed to 
implement it."

優ave Thomas, author of The Pragmatic Programmer

"I'd been programming in Perl for years, and while I don't share the 
anti-Perl sentiments of a lot of Ruby programmers, once I saw Ruby and 
realized you could do all that cool stuff and have the code look so 
elegant and sleek, I was hooked. As I work on a Ruby program and get 
things more and more right, the code seems to disappear gradually from 
the screen."

優avid Alan Black, Associate Professor of Communication at Seton Hall 
University

Supporting Cast
Ruby downloads, libraries and projects

The Ruby source distribution includes the interpreter, standard class 
library, interactive environment, debugger, profiler and Ruby syntax 
support for emacs, and requires a GNU-compatible C compiler. Prebuilt 
packages are also available for Windows and other OSes.

     * The standard source distribution is at 
www.ruby-lang.org/en/download.html; the official English-language home 
page is www.ruby-lang.org/en/.
     * There are several prebuilt packages for Windows. The one I use 
includes an installer, language documentation, and the SciTE 
syntax-highlighting editor: 
www.pragmaticprogrammer.com/ruby/downloads/ruby-install.html.
     * The Ruby Application Archive is the Ruby community's answer to 
Perl's CPAN, a huge list of open-source programs, libraries and 
utilities for Ruby: www.ruby-lang.org/en/raa.html.
     * Ruby syntax support for Visual SlickEdit: 
www.rubygarden.org/ruby?SlickEditRuby.
     * Ruby syntax support for CodeWright: 
www.geocities.com/uncle_gaga/rb_dll.html.
     * Ruby Electric XML, a popular XML-support library: 
www.germane-software.com/software/rexml/.
     * The start of an effort to port Ruby to .NET; "It maybe works (in 
near future)": 
www.geocities.co.jp/SiliconValley-PaloAlto/9251/ruby/nrb.html.

Ruby

Ruby
Online: www.ruby-lang.org/en/
System Requirements:

     Ruby is open source, and can be obtained for a number of platforms: 
various flavors of UNIX (including Linux), DOS, Windows 
95/98/NT/2000/XP, Mac OSX, BeOS, Amiga, Acorn Risc OB and OS/2. It ships 
with Red Hat and other Linux distributions, and with Jaguar (Mac OSX 10.2).

Rating: 4 stars The Rate Sheet
Pros:

    1. Ruby has expressive, clean, readable syntax.
    2. It's scalable, suitable for quick scripts as well as sizable 
projects.
    3. It really is fun葉hings tend to work the first time.

Cons:

    1. I've been bitten myself by that local-scoping thing.
    2. Support and tool availability: You can still fit all the Ruby 
books in a backpack.
    3. The libraries are less extensive than Java's or Python's.




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