typeBound

Type Members

1. trait TypeBoundFunction[TypeBound, Arg[_ <: TypeBound], ReturnVal[_ <: TypeBound]] extends WideningTypeBoundFunction[TypeBound, TypeBound, Arg, ReturnVal]

   

   a function with one type parameter, where both the argument and the return value are types with a single type parameter, bound to the type parameter of the function.

   a function with one type parameter, where both the argument and the return value are types with a single type parameter, bound to the type parameter of the function.

   TypeBound

   the type bound to use for the argument and return value types

   Arg

   the argument type

   ReturnVal

   the return value type

2. class TypeBoundMap[TypeBound, Key[_ <: TypeBound], Val[_ <: TypeBound]] extends BaseTypeBoundMap[TypeBound, Key, Val]

   

   a map where the types for keys and values share a type parameter with the same bounds.

   a map where the types for keys and values share a type parameter with the same bounds. the key and value of each key/value pair are constrained to match on that type parameter. for example, we might have some pet stores that only cater to a single kind of pet:

   trait Pet
   case class Cat(name: String) extends Pet
   case class Dog(name: String) extends Pet
   class PetStore[P <: Pet]
   
   val catStore1 = new PetStore[Cat]
   val catStore2 = new PetStore[Cat]
   val dogStore1 = new PetStore[Dog]

   we can use a TypeBoundMap to store a list of pets of the appropriate type for every pet store:

   var inventories = TypeBoundMap[Pet, PetStore, List]
   inventories += (catStore1 -> List(Cat("cat11"), Cat("cat12"), Cat("cat13")))
   inventories += (catStore2 -> List(Cat("cat21")))
   inventories += (dogStore1 -> List(Dog("dog11"), Dog("dog12")))

   now we can look up pet lists by pet store, with everything coming back as the expected type:

   val cats1: List[Cat] = inventories(catStore1)
   cats1.size should be (3)
   val cats2: List[Cat] = inventories(catStore2)
   cats2.size should be (1)
   val dogs1: List[Dog] = inventories(dogStore1)
   dogs1.size should be (2)
   
   val cat: Cat = inventories(catStore1).head
   cat should equal (Cat("cat11"))
   val dog: Dog = inventories(dogStore1).head
   dog should equal (Dog("dog11"))

   note that the API does not provide methods to add multiple key/value pairs at a time, as each pair needs to be type-checked separately.

   (the code presented here is in test class emblem.typeBoundMap.ScaladocSpec.)

   TypeBound

   the upper bound on the type parameters passed to the Key and Val types

   Key

   the parameterized type of the keys in the map

   Val

   the parameterized type of the values in the map

   See also

   src/test/scala/emblem/typeBoundMap/ for many more examples

3. case class TypeBoundPair[TypeBound, A[_ <: TypeBound], B[_ <: TypeBound], TypeParam <: TypeBound](_1: A[TypeParam], _2: B[TypeParam]) extends Product with Serializable

   

   mimics a pair found in an ordinary map, but preserves the type parameter equality in the two elements of the pair

   mimics a pair found in an ordinary map, but preserves the type parameter equality in the two elements of the pair

   TypeBound

   the upper bound on the type parameters passed into the A and B types of the two elements of this pair

   A

   the parameterized type of the first element of this pair

   B

   the parameterized type of the second element of this pair

   TypeParam

   the type param binding both the A and B types of the two elements of this pair

   _1

   the first element of this type bound pair

   _2

   the second element of this type bound pair

4. trait WideningTypeBoundFunction[TypeBound, WiderTypeBound >: TypeBound, Arg[_ <: TypeBound], ReturnVal[_ <: WiderTypeBound]] extends AnyRef

   

   like a TypeBoundFunction, except that the type bound for the return value is wider than the type bound for the argument.

   like a TypeBoundFunction, except that the type bound for the return value is wider than the type bound for the argument. This is useful for mapWiden and mapValuesWiden methods in TypeKeyMap and TypeBoundMap that return a map with a wider type bound than the original.

   TypeBound

   the type bound to use for the argument type

   WiderTypeBound

   the type bound to use for the return value type

   Arg

   the argument type

   ReturnVal

   the return value type

   See also

   TypeBoundFunction