What are they?
Scripting languages include open source products PHP, Python and
TCL, but also Javascript and Microsoft's ASP. Visual Basic can be
used for scripting as well as building applications. Up and coming
languages include Ruby, which is big in Japan, and Groovy, which
aims to be the number one choice for scripting with Java.
Where did they originate?
Scripting languages have been around since the 1960s. IBM's JCL,
Rexx and Unix shells are used to write shell scripts and macros and
automate tasks. Perl and TCL appeared in the late 1980s, and Python
in the 1990s.
What are they for?
John Ousterhout, creator of TCL, said, "System programming
languages were designed for building data structures and algorithms
from scratch, starting from the most primitive computer elements.
In contrast, scripting languages are designed for gluing: they
assume the existence of a set of powerful components and are
intended primarily for connecting components together.
"System programming languages are strongly typed to help to manage
complexity, while scripting languages are typeless to simplify
connections between components and provide rapid application
development."
What makes them special?
They are high-level languages designed to make fewer demands on the
programmer and the CPU. "Getting the job done fast is typically
prioritised above getting the job done so it runs faster," said a
white paper by scripting tools specialist Active State. "This
approach makes sense when one considers that many programs are run
only periodically, and take effectively no time to execute, but can
take months to write."
Some claim that development times can be slashed when scripting
languages replace C++ or Java. Traditionalists may condemn them as
not suitable for serious coding, but scripting champions point out
that less time coding means more time on testing and
integration.
How difficult are they?
Because they are English-like, and users do not need to grapple
with concepts such as types and classes, they can be learned and
used quickly. TCL is described as having "an almost zero learning
curve".
Where are they used?
Being dynamically typed means scripting languages are able to
handle known and unpredictable objects. This is important in web
applications, which need to interact with unknown third-party
applications.
"The explosion of database-backed websites developed and maintained
by non-engineers led to the sustained explosion of PHP use
worldwide," said Active State's white paper.
What systems do they run on?
The main scripting languages are available, or are in the process
of being made available, for most platforms, although dependence on
volunteer enthusiasts means they are sometimes available for
obscure machines before mainstream platforms.
Not many people know that
Scripting languages are part of what has been called the Lamp -
Linux, Apache, MySQL, Perl/PHP/Python - platform.
What is coming up?
As application requirements become more dynamically changeable,
scripting languages could take over from traditional programming
languages.
Training
There are plenty of free tutorials for scripting languages on the
web.
For Perl, click here
>>
For Python, click here
>>
For tcl, click here
>>
Rates of pay
PHP and Perl developers can look for £24,000 to £35,000, either
with other Lamp skills or with traditional languages such as C++.
Jobs requiring TCL tend to be more technical, are often associated
with Unix, and often pay more.