__   __ __  __  ____   ___      _________________________________________
||   || ||  || ||  || ||__      Hugs 98: Based on the Haskell 98 standard
||___|| ||__|| ||__||  __||     Copyright (c) 1994-2005
||---||         ___||           World Wide Web: http://haskell.org/hugs
||   ||                         Report bugs to: hugs-bugs@haskell.org
||   || Version: March 2005     _________________________________________

Hugs mode: Restart with command line option +98 for Haskell 98 mode

Type :? for help
Calc> [Numeral 4,Mulop Times,LParen,Numeral 7,Addop Plus,Numeral 1,RParen]
Calc> Return 4711
Calc> Return 31
Calc> Fail "syntax error"
Calc> [Leaving Hugs]