Concept函子

Functor

A core type class in Haskell that represents mappable structures. It requires the type constructor to have the kind * -> *, and instances must implement the fmap function.

Timeline (last 90 days)

Oct 17

When defining an instance for Functor, the compiler checks whether the Kind of the target type is * -> *; if a type whose Kind is * (such as Int) is passed in, the compiler reports an error.

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All Facts (1)

Unverified

When defining an instance for Functor, the compiler checks whether the Kind of the target type is * -> *; if a type whose Kind is * (such as Int) is passed in, the compiler reports an error.

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Source Articles

Haskell's Kind System: Type-Level Type ResolutionOct 17