Programming Languages mini-HOWTO
Risto S. Varanka
Jul 22nd 2000
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A brief comparison of major programming languages for Linux and major libraries
for creating graphical user interfaces (GUIs) under Linux
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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 (Graphical User Interface) toolkits at
the moment. This document is intended to be fairly neutral, but I haven't
included all languages available. Since my judgment is undoubtedly biased in
many ways, I advise serious developers to check out the sites that do a better
job in listing all languages and libraries. Also note that only the Linux
implementations of the languages and GUI toolkits are covered, 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,
especially beginners. A question mark in the tables indicates lack of
information. If you can fill it in, please contact the author.
1.1 Latest Version of the Document
You can find the latest modifications at http://www.helsinki.fi/~rvaranka/
Computer/Linux/HOWTO/
1.2 Copyright
Copyright (c) 2000 Risto Varanka.
1.3 License
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1.4 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INFORMATION CONTAINED IN THIS DOCUMENT MAY BE INCORRECT OR OUTDATED.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.
1.5 Author
You are welcome to send feedback to the author at: risto.varanka@helsinki.fi.
Author's web site can be found at http://www.helsinki.fi/~rvaranka/.
1.6 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.
1.7 Links
Exhaustive lists of Linux development libraries and tools:
* Freshmeat
* Linux_Development_Tools
* linuxprogramming.com
The Hacker_FAQ 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 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
C, Lisp and Perl are traditional hacking languages in the GNU/Linux culture;
Python, PHP, Java and C++ have gained new ground recently.
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 unscientific ``benchmarking'' of the languages
would be to implement a simple sorting algorithm in all of them and
compare running times. This of course does not measure the performance of
the actual language - since that concept does not make sense - but only
the implementation. Of course it's also not a very reliable or thorough
method, but it would give an example how running times in different
languages can differ. 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. RAD can be powerful when 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
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: Spreading to new areas, eg. e-commerce infrastructure
Lisp
Beginner: Yes - OOP: Functional
Examples: Emacs modes (for Elisp), AI
Comments: Variants Elisp, Clisp and Scheme
Fortran
Beginner: No - OOP: No
Examples: Mathematical (scientific) applications
Comments: Variants f77 and f90/95
C
Beginner: No - OOP: No
Examples: System programming, applications
Comments:
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 other
kinds of scripting - often they can achieve the same goals, and you have the
option of choosing between native shell and a separate 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 on programming languages, lots of info and opinions
* TCL
* Perl
* Python
* PHP
* Java
* clisp
3. GUI Toolkits
The standard graphical subsystem for UNIX and Linux, called X, has its own
libraries for GUI development. They provide a low-level programming interface
to X, but tend to be hard to use. Old end-user applications and other toolkits
of course make good use of them. Nowadays the Linux GUI scene is dominated by
GTK+ and Qt, since two popular, complete user environments - GNOME and KDE -
are based on them.
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+, TK and GNUstep 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
_____________________________________________________________________________
|Library|Beginner|License____|Language___|Bindings___|Examples___|Comments____|
| | | | |Perl, |make | |
|TK |Yes |Free |TCL |Python, |xconfig, | |
|_______|________|___________|___________|others_____|TKDesk_____|____________|
| | | | |Perl, C++, | | |
|GTK+ |No |Free (LGPL)|C |Python, |GNOME, Gimp|Very popular|
|_______|________|___________|___________|many_others|___________|____________|
| | |Free for | |Python, | | |
|QT |No |open source|C++ |Perl, C, |KDE |Very popular|
|_______|________|___________|___________|others?____|___________|____________|
| | | | |Python, |Netscape, |Lesstif isa |
|Motif |No |Non-free |C/C++ |others? |Wordperfect|free |
|_______|________|___________|___________|___________|___________|replacement_|
| | | | | |None widely| |
| | | | |Guile, |known, but |GNUstep is |
|GNUstep|No |Free (LGPL)|Objective C|Java? |see the |still under |
| | | | | |application|development |
|_______|________|___________|___________|___________|list_______|____________|
3.3 Links
* TK
* GTK+
* QT
* Motif
* GNUstep