| Line No. | Rev | Author | Line |
|---|---|---|---|
| 1 | 1 | paulosilva | |
| 2 | {-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies, FlexibleInstances, | ||
| 3 | TypeSynonymInstances, OverlappingInstances #-} | ||
| 4 | {-# OPTIONS_GHC -Wall #-} | ||
| 5 | |||
| 6 | ------------------------------------------------------------------------------- | ||
| 7 | |||
| 8 | {- | | ||
| 9 | Module : Data.Stream | ||
| 10 | Description : Streams of values. | ||
| 11 | Copyright : (c) Paulo Silva | ||
| 12 | License : LGPL | ||
| 13 | |||
| 14 | Maintainer : paufil@di.uminho.pt | ||
| 15 | Stability : experimental | ||
| 16 | Portability : portable | ||
| 17 | |||
| 18 | -} | ||
| 19 | |||
| 20 | ------------------------------------------------------------------------------- | ||
| 21 | |||
| 22 | module Data.Stream where | ||
| 23 | |||
| 24 | ------------------------------------------------------------------------------- | ||
| 25 | |||
| 26 | class Stream a v | a -> v where | ||
| 27 | headStr :: a -> v | ||
| 28 | tailStr :: a -> a | ||
| 29 | |||
| 30 | ------------------------------------------------------------------------------- | ||
| 31 | |||
| 32 | instance Stream [a] a where | ||
| 33 | headStr = head | ||
| 34 | tailStr = tail | ||
| 35 | |||
| 36 | ------------------------------------------------------------------------------- | ||
| 37 | |||
| 38 | instance Stream Int Int where | ||
| 39 | headStr n = n | ||
| 40 | tailStr n = succ n | ||
| 41 | |||
| 42 | ------------------------------------------------------------------------------- | ||
| 43 | |||
| 44 | instance Stream [String] String where | ||
| 45 | headStr = head | ||
| 46 | tailStr = tail | ||
| 47 | |||
| 48 | ------------------------------------------------------------------------------- | ||
| 49 |