4
expect them to, with very few special cases or exceptions. And that really does make a
difference when you're programming.
We call Ruby a transparent language. By that we mean that Ruby doesn't obscure the
solutions you write behind lots of syntax and the need to churn out reams of support code just
to get simple things done. With Ruby you write programs close to the problem domain. Rather
than constantly mapping your ideas and designs down to the pedestrian level of most
languages, with Ruby you'll find you can express them directly and express them elegantly.
This means you code faster. It also means your programs stay readable and maintainable.
Using Ruby, we are constantly amazed at how much code we can write in one sitting, code
that works the first time. There are very few syntax errors, no type violations, and far fewer
bugs than usual. This makes sense: there's less to get wrong. No bothersome semicolons to
type mechanically at the end of each line. No troublesome type declarations to keep in sync
(especially in separate files). No unnecessary words just to keep the compiler happy. No error-
prone framework code.
So why learn Ruby? Because we think it will help you program better. It will help you to focus
on the problem at hand, with fewer distractions. It will make your life easier.
What Kind of Language Is Ruby?
In the old days, the distinction between languages was simple: they were either compiled, like
C or Fortran, or interpreted, like BASIC. Compiled languages gave you speed and low-level
access; interpreted languages were higher-level but slower.
Times change, and things aren't that simple anymore. Some language designers have taken to
calling their creations "scripting languages." By this, we guess they mean that their languages
are interpreted and can be used to replace batch files and shell scripts, orchestrating the
behavior of other programs and the underlying operating system. Perl, TCL, and Python have
all been called scripting languages.
What exactly is a scripting language? Frankly we don't know if it's a distinction worth making.
In Ruby, you can access all the underlying operating system features. You can do the same
stuff in Ruby that you can in Perl or Python, and you can do it more cleanly. But Ruby is
fundamentally different. It is a true programming language, too, with strong theoretical roots
and an elegant, lightweight syntax. You could hack together a mess of "scripts" with Ruby, but
you probably won't. Instead, you'll be more inclined to engineer a solution, to produce a
program that is easy to understand, simple to maintain, and a piece of cake to extend and
reuse in the future.
Although we have used Ruby for scripting jobs, most of the time we use it as a general-
purpose programming language. We've used it to write GUI applications and middle-tier server
processes, and we're using it to format large parts of this book. Others have used it for
managing server machines and databases. Ruby is serving Web pages, interfacing to
databases and generating dynamic content. People are writing artificial intelligence and
machine learning programs in Ruby, and at least one person is using it to investigate natural
evolution. Ruby's finding a home as a vehicle for exploratory mathematics. And people all over
the world are using it as a way of gluing together all their different applications. It truly is a
great language for producing solutions in a wide variety of problem domains.
