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我有以下几种类型:推导查看代数数据类型
data Suit = Club | Diamond | Heart | Spade deriving Show
data Rank = R2 | R3 | R4 | R5 | R6 | R7 | R8 | R9 | R10 | Jack | Queen | King | Ace deriving Show
data JokerColor = Red | Black deriving Show
data JCard = NormalCard Suit Rank | JokerCard JokerColor
我怎么能显示JCard?目前我得到No instance for (Show JCard)
谢谢!我以前得到无关的错误,并认为这个语法是不正确的... – 2012-03-11 15:56:16