syntactic sugar improving 'assert' and 'error'

 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.
 .
 Note that for most of these functions to have any effect, assertions
 need to be enabled, e.g., by including in .cabal file the following line:
 .
 ghc-options: -fno-ignore-asserts
 .
 This package provides a library for the Haskell programming language.
 See http://www.haskell.org/ for more information on Haskell.