Intersection type

Article summary

In type theory, an intersection type can be allocated to values that can be assigned both the type \sigma and the type \tau . This value can be given the intersection type \sigma \cap \tau in an intersection type system. Generally, if the ranges of values of two types overlap, then a value belonging to the intersection of the two ranges can be assigned the intersection type of these two types. Such a value can be safely passed as argument to functions expecting either of the two types. For example, in Java the class implements both the and the interfaces. Therefore, an object of type can be safely passed to functions expecting an argument of type and to functions expecting an argument of type . Intersection types are composite data types. Similar to product types, they are used to assign several types to an object. However, product types are assigned to tuples, so that each tuple element is assigned a particular product type component. In comparison, underlying objects of intersection types are not necessarily composite. A restricted form of intersection types are refinement types. Intersection types are useful for describing overloaded functions.…

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