Yacas (Yet Another Computer Algebra System) is a small and highly flexible computer algebra language. The syntax uses a infix-operator grammar parser. The distribution contains a small library of mathematical functions, but its real strength is in the language in which you can easily write your own symbolic manipulation algorithms. It supports arbitrary precision arithmetic. The current version is 1.0.28 (the first release was 1.0.0). The language is very much in a finished state. Any code written for it should be usable in future versions. Also, the language should prove very easy to learn. Yacas is written in very clean c++ code, and is very portable . It can compile stand-alone, and is easily embeddable. Yacas contains a native arbitrary precision arithmetic module, but can also be used with GMP. Things implemented include: arbitrary precision, rational numeric, vector, complex, and matrix computations (including inverses and determinants and solving matrix equations), derivatives, solving, Taylor series, numerical solving (Newtons method), and a lot more non-mathematical algorithms. The language natively supports variables and user-defined functions. There is basic support for polynomials.