List of Cross-Platform Programming Languages with Open Source Licenses

Question

I think it would be valuable to have a list of all the programming languages that have a significant open source component (i.e. I can do a significant amount of work in it without using any non-free components) and that are cross platform (i.e. that will run on all the major platforms: Windows, Mac OS X, and Linux/BSD), along with information about how they are useful. That way, one could pick out the ideal language for a particular project if a choice is available.

Therefore, it would be great if you could list all the languages you know, include at least a bit about the merit/usefulness of each, and maybe some interesting points (like a good IDE, important software libraries, etc).

Links are good too (link to the developer's site or to a major resource site).

This would be a good complement to the list of programming books (http://stackoverflow.com/q/194812/289380).

EDIT: Oh, and no flame wars :).

EDIT 2: I have set up a Wiki to hold this list and a list of the programming books linked to above: http://programref.wikia.com/

Answer 1

Language: Java (OpenJDK) - http://openjdk.java.net/ IDE: Eclipse, Netbeans

Answer 2

C++: The quinessential OOP programming language. Massive number of libraries to do just about whatever you could imagine. Some IDE's include Code::Blocks, Dev-C++, Netbeans, and Eclipse.

Answer 3

Python: http://www.python.org

Fast to develop in, huge standard library, lots of support, great interpreter, great scripting language.

Perl: Do I really need to say more?

Ruby: http://www.ruby-lang.org

Another great scripting language, very powerful, OO to the core but still pragmatic. Very popular right now, with lots of addon libraries.

Lua: http://www.lua.org

A small,fast scripting language designed to be embedded in other applications. Small standard library with a reasonable set of basic stuff and additional libraries / C extensions to do other stuff. Very popular in games - the World of Warcraft client UI is built and extended in Lua.