programming-for-dummies

Finding an Interpreter 91
In the old days, many companies sold language interpreters (the most popular
were interpreters for running BASIC programs), but nowadays, most interpreters
are given away for free as part of an operating system (such as Mac OS X) or
another program (such as Microsoft Word). Interpreters for open source programming
languages, such as Perl, Python, and Ruby, are also given away for free.
Operating system interpreters
One of the most common uses for an interpreter is for creating short programs
to automate another program, such as an operating system. The Mac OS X
operating system includes an interpreter, dubbed Script Editor, for running programs
with the AppleScript language. After you write a program (script) that’s
particularly useful, you can even compile it into a standalone program, too.
Book I
Chapter 4
Programming Tools
The Script Editor program is usually buried inside the Applications folder on
your Macintosh’s hard disk.
Although Windows doesn’t include a similar macro language interpreter, you
can visit Microsoft’s web site (www.microsoft.com/downloads) and
download Microsoft PowerShell, a free interpreter.
PowerShell is designed for system administrators (people who need to control
multiple computers, such as those connected to a network) to control and
automate Windows. By writing simple programs in PowerShell, administrators
can automate their routine tasks, such as starting or stopping a program,
or moving files from one location to another.
PowerShell consists of simple commands (called command-lets or cmdlet)
that perform a single task. By combining multiple cmdlets together where
one cmdlet feeds data into another cmdlet, you can create more complicated
programs.
Web page interpreters
Nearly every Web browser comes with a JavaScript interpreter. Web page
designers use JavaScript for creating interactive Web pages, verifying information
typed on a Web page (such as a username and password), or opening
pop-up windows that display advertisements.
JavaScript is the programming language used to create DashBoard widgets,
which are mini-programs that can pop up on the screen of a Mac OS X computer.
Most Web browsers include a free JavaScript interpreter, but to avoid trademark
problems, Microsoft calls their JavaScript interpreter JScript, which
they include with their Internet Explorer browser.