Extract the first component of a pair.
Fst is an application for construction and running of finite state transducers. The application was written purely in Haskell, and is intended to be a tool for the Haskell programmer, especially for ones that develop language applications.
Obtain the Haskell value referenced by a stable pointer, i.e., the same value that was passed to the corresponding call to makeStablePtr. If the argument to deRefStablePtr has already been freed using freeStablePtr, the behaviour of deRefStablePtr is undefined.