我想使用參數化類型類。下面是我的源代碼:Haskell類型類別中的模糊類型
class (CContext3D c k v) => CBuilder3D c a k v where
build3D :: c -> a -> String -> HSL HLangJS HLangJS
在編譯時我收到以下錯誤:
Could not deduce (CBuilder3D c a k0 v0)
from the context: CBuilder3D c a k v
bound by the type signature for:
build3D :: CBuilder3D c a k v =>
c -> a -> String -> HSL HLangJS HLangJS
下面的代碼工作正常:
class (CContext3D c KeyContext3D String) => CBuilder3D c a where
build3D :: c -> a -> String -> HSL HLangJS HLangJS
這怎麼可能釋放類的實例取決於k和v類型?