InteLib is a library of C++ classes that lets you do Lisp/Scheme programming within your C++ programs, even without any additional preprocessing, without all those calling conventions. You can write code that is accepted by a C++ compiler while thinking in a "Lisp/Scheme mode", and the code you write will look much like Lisp/Scheme code, although it will be pure C++.
Mathomatic is a portable, general-purpose computer algebra system (CAS) that can solve, differentiate, simplify, combine, and compare algebraic equations, perform standard, complex number, modular, and polynomial arithmetic, etc. It does some calculus and is very easy to compile/install, learn, and use. The symbolic math application with a simple command-line interface is designed to be a colorful algebra calculator that is reliable, responsive, and convenient to use. The symbolic math library is lightweight and easy to include in other software, due to being written entirely in C with no additional dependencies.
Open Tool Kit (Otk) is a portable widget library for making graphical user interfaces for C programs. It emphasizes simplicity for the application programmer without eliminating capability. Based on OpenGL, Otk supports Linux, Unix, and other OSs neutrally and efficiently. It is simple and compact, and it strives for easy compilation and linking to other applications. In seeking to address several issues associated with earlier graphics APIs, Otk explores some interesting methods, such as window-relative layout instead of pixel-based layout.
Opticks Extras is a set of official extensions for the Opticks application. The Spectral Processing extension adds multi-spectral and hyper-spectral processing capability to Opticks. The IDL Scripting extension integrates an IDL interpreter directly into the Opticks application. The Python Scripting Extension integrates a Python interpreter directly into the Opticks application.
Libee is an event expression library that is inspired by the upcoming CEE standard. Right now, it provides capabilities to generate and emit messages in a set of standard formats and read a set of different input formats. Libee also comes with a handy conversion tool that provides format transformation without the need to program.