This library contains syntactic sugar that makes it easier to write simple contracts with 'assert' and 'error' and report the values that violate contracts. The original 'assert' function is here re-exported for convenience.
Make sure to enable assertions for your cabal package, e.g., by setting
ghc-options: -fno-ignore-asserts
in your .cabal file. Otherwise, some of the functions will have no effect at all.
The library emerged from the chaos of the tons of assertions (sometimes augmented by comments and trace printouts) and 'error' calls in the LambdaHack game engine.