(GHC) A Haskell 1.2 compiler written in Haskell by the AQUA project at Glasgow University, headed by Simon Peyton Jones throughout the 1990's. GHC can generate either C or native code for SPARC, DEC Alpha and other platforms. It can take advantage of features of gcc such as global register variables and has an extensive set of optimisations. GHC features an extensible I/O system based on a "monad", in-line C code, fully fledged unboxed data types, incrementally-updatable arrays, mutable reference types, generational garbage collector, concurrent threads. Time and space profiling is also supported.