C/Invoke is a library which can call C functions at runtime with no prior knowledge of the function prototypes. This capability is used to allow any language to call native libraries without writing a separate module in C, similar to the P/Invoke functionality of the .NET framework.
GraphicsMagick is a robust collection of tools and libraries which support reading, writing, and manipulating an image in over 90 major formats including popular formats like DPX, DICOM, BMP, GIF, JPEG, JPEG-2000, PDF, PNG, PNM, SVG, and TIFF. A high-quality 2D renderer is included, which provides a subset of SVG capabilities. C, C++, Perl, Tcl, and Ruby are supported. Originally based on ImageMagick, GraphicsMagick focuses on performance, minimizing bugs, and providing stable APIs and ABIs. It runs on all modern variants of Unix, Windows, and Mac OS X.
LuaRocks is a deployment and management system for modules in the Lua programming language. It aims to provide facilities for Lua such as those from module systems of other scripting languages, such as Ruby's RubyGems or Perl's CPAN. LuaRocks allows Lua modules to be installed as self-contained packages called "rocks", which also contain version and dependency information.
The QtLua library aims to make Qt 4 applications scriptable using the Lua scripting language. It is an alternative to the QtScript module. QtLua does not generate or use generated binding code for Qt. Instead it provides useful C++ wrapper classes to make C++ and Lua objects accessible from both Lua and C++. It takes advantage of the Qt meta object system to expose QObject members to Lua scripts and comes with user manual and examples.
Xapian is a search engine library, scalable to collections containing hundreds of millions of documents. It's written in C++ with bindings for Perl, Python, PHP, Java, Tcl, C#, Ruby, and Lua. It is a highly adaptable toolkit that allows developers to easily add advanced indexing and search facilities to their own applications. It supports the Probabilistic Information Retrieval model and also a rich set of boolean query operators. Omega is a Web search application built upon the Xapian library. It can index a Web server's document tree (including HTML, PDF, OpenOffice, MS Word/Excel/Powerpoint/Works, WordPerfect, RTF, PS, etc.), or data exported from arbitrary sources (e.g. SQL databases).