a language tool that provides a framework for constructing recognizers, compilers, and translators from grammatical descriptions containing Java, C#, C++, or Python actions. It provides excellent support for tree construction, tree walking, and translatio
a 3D engine: a library of subroutines for 3D rendering and game development. The library is C++ with a set of Python bindings. Game development with Panda3D usually consists of writing a Python program that controls the the Panda3D library.
a free user interface builder for GTK+ and GNOME interfaces designed are saved as XML, and by using the libglade library these can be loaded by applications dynamically as needed. (Glade can also generate C code)
an experimental Python-to-C++ compiler. It accepts pure but implicitly statically typed Python programs and generates optimized C++ code. (Google sponsoring)
an interface for array-oriented data access and a library that provides an implementation of the interface. The netCDF library also defines a machine-independent format for representing scientific data.
a robust, somewhat scalable, cross-platform client-server messaging system for dynamic distributed applications that runs under any POSIX-compliant operating system.
a Free C++/Python GIS Toolkit for developing mapping applications. Above all Mapnik is about making beautiful maps. It is easily extensible and suitable for both desktop and web development.