[Haskell-beginners] distinguished types

Stephen Tetley stephen.tetley at gmail.com
Sat Feb 13 16:11:38 EST 2010

Hello Rick

I suspect that in the context of Oleg's piece, a "distinguished type"
is merely a type that can be distinguished rather than a common
concept like say a "dynamic type" or a "sum type". As he mentions
further some types can have only one value such as Haskell's unit type
- ().

I can't find a definition for "distinguished type" in any of the
programming books I've checked: various Haskell ones, Pierce's TAPL,
and and various Scheme ones - Friedman, Wand and Haynes's EoPL, Lisp
in Small Pieces and Springer and Friedman's Scheme and the Art of
Programming; nor from a few searches on the web.

Best wishes


On 13 February 2010 20:29, Rick Murphy <rick at rickmurphy.org> wrote:

> 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.

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