th-cas is a Computer Algebra System (CAS) for Haskell that performs symbolic mathematics operations at compile-time using Template Haskell. It provides both interactive usage (similar to Mathematica) and compile-time optimization for mathematical computations with zero runtime overhead. . Features include: . * Symbolic differentiation with automatic simplification . * Symbolic integration using the Risch-Norman heuristic algorithm . * Linear and polynomial equation solvers . * Gröbner basis computation for multivariate polynomial systems . * Pattern matching and coefficient extraction . * Compile-time code generation via Template Haskell . The library supports polynomial operations (GCD, LCM, factorization), trigonometric and exponential functions, and advanced algorithms including Hermite reduction for rational functions and the Extended Euclidean algorithm. . With 150+ test cases, th-cas provides reliable symbolic computation for both runtime and compile-time mathematical operations in Haskell.