Greetings and thanks in advance for all the great work on this list. Being new Haskell I hope someone could help me clarify the use of the term *distinguished type* in relation to Haskell 98 as well as confirm my understanding of the construction of a distinguished type in GHC. I understand from [1] that a distinguised type is defined as a type with only one non-bottom value and that value is in fact identical to the name of the type. [1] provides the unit type () as an example of a Haskell distinguished type. Would it be accurate to say that an approach to creating distinguished types in Haskell is to create data types with a single constructor whose name is identical to the data type name? More specifically, would
data F = F deriving (Show)
create a distinguished type F in Haskell? I've searched the Haskell Report, but there's no indication that the report recognizes distinguished types. Is that true and if so why ? 1. http://okmij.org/ftp/Scheme/misc.html -- Rick cell: 703-201-9129 web: http://www.rickmurphy.org blog: http://phaneron.rickmurphy.org