Programming Languages mini-HOWTO
Risto S. Varanka, <risto.varanka@helsinki.fi>
v, 6 January 2000

A brief comparison of major programming languages for Linux and major
libraries for creating graphical user interfaces (GUIs) under Linux
______________________________________________________________________

Table of Contents

1. Introduction

1.1 Copyright
1.2 License
1.2.1 Requirements of Modified Works
1.3 Disclaimer
1.4 Author
1.5 Credits
1.6 Links

2. Programming Languages

2.1 Concepts in the Table
2.2 Major Languages
2.3 Shell Programming
2.4 Other Languages
2.5 Links

3. GUI Toolkits

3.1 Concepts in the Table
3.2 Major GUI Toolkits
3.3 Links

______________________________________________________________________

1. Introduction

Linux is a fascinating operating system because it lets any user
participate in its development. The variety of available languages,
however, can be confusing to beginning Linux developers. This document
lists the most common options for everyday development and states some
key facts about them. (Well, ``most common'' and ``key'' as I perceive
them.) My aim is neither to review the languages nor to determine
which one is the best. Each language is a tool that fits some jobs
and some tastes. You can get further (often conflicting) information
easily, if you ask around or keep your ears open. The Links sections
in this document will give you some pointers for your own research.

There is a plethora of languages and libraries for Linux, so this
document only covers the most common languages and GUI toolkits at the
moment. Also note that the languages and GUI toolkits are seen from
the Linux point of view, their features on other platforms are not
discussed or implied.

This document is a recent addition to the LDP, so there has not been
opportunity for much community feedback. However, it is released in
hopes that it will prove useful for people interested in programming
under Linux. A question mark in the tables indicates lack of
information. If you can fill it in, please contact the author.

1.1. Copyright

1.2. License

The following license terms apply to all LDP documents, unless
otherwise stated in the document. The LDP documents may be reproduced
and distributed in whole or in part, in any medium physical or
electronic, provided that this license notice is displayed in the
reproduction. Commercial redistribution is permitted and encouraged.
Thirty days advance notice via email to the author(s) of
redistribution is appreciated, to give the authors time to provide
updated documents.

1.2.1. Requirements of Modified Works

All modified documents, including translations, anthologies, and
partial documents, must meet the following requirements:

1. The modified version must be labeled as such.

2. The person making the modifications must be identified.

3. Acknowledgement of the original author must be retained.

4. The location of the original unmodified document be identified.

5. The original author's (or authors') name(s) may not be used to
assert or imply endorsement of the resulting document without the
original author's (or authors') permission.

In addition it is requested that:

1. The modifications (including deletions) be noted.

2. The author be notified by email of the modification in advance of
redistribution, if an email address is provided in the document.

As a special exception, anthologies of LDP documents may include a
single copy of these license terms in a conspicuous location within
the anthology and replace other copies of this license with a
reference to the single copy of the license without the document being
considered ``modified'' for the purposes of this section.

Mere aggregation of LDP documents with other documents or programs on
the same media shall not cause this license to apply to those other
works.

All translations, derivative documents, or modified documents that
incorporate any LDP document may not have more restrictive license
terms than these, except that you may require distributors to make the
resulting document available in source format.

1.3. Disclaimer

THIS DOCUMENT COVERS A LARGE AND CONSTANTLY CHANGING DOMAIN.
THEREFORE, THE INFORMATION CONTAINED IN THIS DOCUMENT MAY BE INCORRECT
OR OUTDATED. ALL USE OF THIS DOCUMENT AND ALL INFORMATION CONTAINED IN
IT IS AT YOUR OWN RISK. THE AUTHOR DOES NOT GIVE ANY WARRANTY OR
GUARANTEE, EITHER EXPLICIT OR IMPLIED.

1.4. Author

You are welcome to send feedback to the author at:
risto.varanka@helsinki.fi <mailto:risto.varanka@helsinki.fi>.

Author's web site can be found at http://www.helsinki.fi/~rvaranka/
<http://www.helsinki.fi/~rvaranka/>.

1.5. Credits

I am thankful to several people who commented on language issues.
These conversations have given me a better view of the different
languages, and I hope future conversations will allow this mini-HOWTO
to mature over time. Especially I would like to thank the people at
the IRCNet channel #linux: Morphy, Bluesmurf, Vadim, Zonk^, Rikkus and
others whose names I have forgotten. Thanks go also to Stig Erik
Sandoe for helpful comments.

1.6. Links

Exhaustive lists of Linux development libraries and tools:

� Freshmeat <http://www.freshmeat.net/appindex/development/>

� Linux Development Tools <http://www.hotfeet.ch/~gemi/LDT/>

� linuxprogramming.com <http://www.linuxprogramming.com/>

The Hacker FAQ <http://www.tuxedo.org/~esr/faqs/hacker-howto.html> by
Eric S. Raymond is another interesting text for novice Linux
developers. It concentrates on some cultural and psychological aspects
of open source development.

Other LDP documents <http://www.linuxdoc.org/> covering general
programming subjects include the Reading List HOWTO and the Linux
Programmer's Guide - several more have been written on specific
subjects.

2. Programming Languages

2.1. Concepts in the Table

Language
A common name of the language.

Beginner
Indicates how well suited the language is for people with little
programming experience. A language marked with ``yes'' should be
viable for a beginner's first programming language.

Performance
How fast your applications are likely to run when you put them
into production use. Performance depends more on your
algorithmic programming skills than the actual language. As a
rule of thumb, C, C++ and Fortran are sometimes necessary
because they can offer better performance than other languages -
at other times they might be unwieldy for the desired purpose.
(One idea for ``benchmarking'' the languages would be to
implement a simple sorting algorithm in all of them and compare
running times. Anybody want to help me with this?)

OOP, Object-Oriented Programming vs. other paradigms
Object-oriented programming is an important programming paradigm
that is gaining popularity. In object oriented programming,
data structures and algorithms are integrated into units, often
called classes. OOP is often contrasted with procedural
programming (which uses separate algorithms and data
structures). It is not strictly dependent on language: you can
do OOP in languages not listed as such (C for example), and
program in the procedural style in languages that are listed as
OOP. I've listed as OOP languages that have special features or
add-ons to facilitate OOP. Functional languages (Lisp for
example) are a bit different breed - among other things,
functional programming is a superset of OOP. Logic programming
(Prolog), also called declarative programming, on the other
hand, is not related to the other types of programming in a
similar sense.

RAD, Rapid Application Development
More dependent on the tools you are using than the actual
language. There is a HOWTO on GUI development tools for Linux,
although it's out of date. With a good graphical tool you can
do RAD. Sometimes RAD is based on code reuse as well, so free
software could provide a good starting point.

Examples
Mentions fields of programming the language is most often used
in. Other good (and bad) uses exist, but they are less typical.

Comments
Additional information on the language, like capacities and
dialects.

2.2. Major Languages

PERL
Beginner: Yes - OOP: Yes
Examples: Scripting, sysadmin, www
Comments: Powerful for handling text and strings, very popular

Python
Beginner: Yes - OOP: Yes
Examples: Scripting, application scripting, www
Comments:

TCL
Beginner: Yes - OOP: No
Examples: Scripting, sysadmin, applications
Comments:

PHP
Beginner: Yes - OOP: Yes
Examples: Www
Comments: Popular for web databases

Java
Beginner: Yes - OOP: Yes
Examples: Cross-platform applications, www
Comments:

Lisp
Beginner: Yes - OOP: Functional
Examples: Emacs modes (for elisp), AI
Comments: Variants Elisp, Clisp and Scheme

Fortran
Beginner: No - OOP: No
Examples: Mathematical applications
Comments: Variants f77 and f90/95

C
Beginner: No - OOP: No
Examples: System programming, applications
Comments: Very popular

C++
Beginner: No - OOP: Yes
Examples: Applications
Comments:

2.3. Shell Programming

Shells are an important programming environment, too. I haven't
covered them because I don't understand the field very thoroughly yet.
Knowledge of shells is important for anyone who works on Linux
regularly, more so for system administrators. There are similarities
between shell programming and scripting - often they can achieve the
same goals, and you have the option of choosing between native shell
and a scripting language. Among the most popular shells are bash,
tcsh, csh, ksh and zsh. You can get basic information on your shell
with the man command, man bash for example.

2.4. Other Languages

Other languages of note: AWK, SED, Smalltalk, Eiffel, ADA, Prolog,
assembler, Objective C, Logo, Pascal (p2c converter)

2.5. Links

� A general info site <http://www.tunes.org/Review/Languages.html> on
programming languages, lots of info and opinions

� TCL <http://www.scriptics.com/>

� PERL <http://www.perl.org/>

� Python <http://www.python.org/>

� PHP <http://www.php.net>

� Java <http://www.javasoft.com/>

� clisp <http://clisp.cons.org/~haible/packages-clisp.html>

3. GUI Toolkits

3.1. Concepts in the Table

Library
Common name or abbreviation of the toolkit.

Beginner
Whether the toolkit is suitable for a newbie programmer.

License
Different licenses for different GUI toolkits have practical
significance. GTK+ and TK licenses allow you to develop both
open source and closed source applications without paying for a
license. Motif license requires payment, while the QT license
requires payment only if you write closed source programs.

Language
The language that is most often used with the toolkit.

Bindings
Other languages which can use the toolkit.

Examples
Applications that use the toolkit.

Comments
Additional information on the toolkit.

3.2. Major GUI Toolkits

3.3. Links

� TK <http://www.scriptics.com/>

Library Beginner License Language Bindings Examples
TK Yes Free TCL PERL, Python, others make xconfig, TKDesk
GTK+ No Free (LGPL) C PERL, C++, Python, many others GNOME, Gimp
QT No Free for open source C++ Python, PERL, C, others? KDE
Motif No Non-free C/C++ Python, others? Netscape, Wordperfect

� GTK+ <http://www.gtk.org/>

� QT <http://www.troll.no/>

� Motif <http://www.metrolink.com/>