Language eXtensions for Scientific Computation provide all features
indispensable for modern numerical software development, such as :
   - Operator concept (user-defined operators)
   - Overloading concept
   - Module concept
   - Dynamic arrays
   - Controlled rounding
   - Predefined arithmetic data types real, (extended real), complex,
     interval, complex interval, and corresponding vector and matrix types
   - Predefined arithmetic operators of highest accuracy for the arithmetic
     data types
   - Predefined elementary functions of highest accuracy for the arithmetic
     data types
   - Data type dotprecision for the exact representation of dot products
   - Library of mathematical problem-solving routines with automatic result
     verification and high accuracy

WWW: http://www.math.uni-wuppertal.de/~xsc/