Hugs is a small, portable Haskell interpreter written in C runs on almost any machine. Hugs is best used as a Haskell program development system: it boasts extremely fast source code interpretation, supports incremental interpretation, and has the convenience of an interactive interpreter (within which one can move from module to module to test different portions of a program). However, being an interpreter, it does not nearly match the run-time performance of, for example, GHC, nhc98, or HBC. Hugs 98 is conformant with Haskell 98. Available for all Unix platforms including Linux, DOS, Windows 3.x, and Win 32 (Windows 95, Win32s, NT) and Macintoshes. It has many libraries including Win32 libraries, a foreign interface mechanism to facilitate interoperability with C, and the Windows version has a graphical user interface called WinHugs. Explanations of some common Hugs error messages and their causes can be found on Simon Thompson's page.