Just for the record, Cobol has a long history of specifying local rounding options. More recently, the options for rounding are elaborated in the context of adding standard arithmetic. http://www.cobolportal.com/j4/files/05-0152.doc Ralf

-----Original Message----- From: haskell-bounces@haskell.org [mailto:haskell-bounces@haskell.org] On Behalf Of Bjorn Lisper [...] He was very careful to give the language a good design also regarding floating-point computations. His design choice, as regards rounding, was to allow the compiler to choose rounding mode by default (thus allowing more freedom for optimization), while providing a set of special arithmetic operators, with specified rounding modes, to use when more explicit control is needed.

He also proposed a special construct "letctrl ... in e", where the "..." are a list of directives telling how to interpret and evaluate the expression e. One possible directive is "RoundingMode = ..." to set the rounding mode locally in e. Other directives control, for instance, whether optimizations like x*0.0 -> 0.0 are allowed in e, whether to force strict evaluation of all subexpressions (so optimizations cannot affect exceptions), to set allowed miminum accuracy, etc.

The language has exception handling (including a "handle" construct to catch exceptions), which also takes care of floating-point exceptions.