agreement between Netscape and Sun to try to leverage the buzz about Java
and make JavaScript the shiny, new programming language for the web. You
will occasionally see JavaScript referred to using its original name,
EMCAScript. The JavaScript trademark is now owned by Oracle under a
license from the technology creators, including Mozilla, the descendant of
Netscape.
JavaScript is easily the most popular scripting language for the web, widely
used in programming web applications. Combined with HTML and CSS, it is
used to create interesting, diverse, and powerful websites. JavaScript has
spawned tons of extensions and development kits, such as Node.js and JSP. It
is commonly combined with other technologies, like XML, to create
interactive websites using Ajax. Information is often passed using JavaScript
Object Notation, or JSON, which is rapidly becoming the successor to XML.
Whether people love JavaScript or hate it, it is universally acknowledged as a
“must know” technology for programmers today.
To use JavaScript on Ubuntu, you write programs in your favorite text editor.
Nothing special is needed. Put the script somewhere and open it with your
web browser.
Lisp
Lisp is slightly younger than Fortran—first released in 1958—making it not
quite the oldest language discussed in this chapter. Clojure, discussed earlier,
is a dialect of Lisp. Lisp is designed to process lists. Linked lists are the
language’s main data structure. It was originally created to be used as a
practical mathematical notation for computer programs but became popular as
a program for research in artificial intelligence.
There have been many versions of Lisp over the years, as well as many
dialects. The most commonly used “regular Lisp” in use today is probably
ANSI Common Lisp, of which there are also multiple implementations. To
use ANSI Common Lisp on Ubuntu, install the package clisp. Type clisp
from the command line to bring up a REPL (from which you may exit by
entering quit).
Many Lisp programmers prefer to use emacs as their editor, which was
written in a Lisp dialect called elisp. emacs includes many useful tools for
Lisp and has other plug-ins available. From here it is easy to save code in
files, compile it, and enable it to be run as programs rather than from the
REPL interface.
Another interesting dialect of Lisp is Scheme, which is also available from the