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1 parent 08decc6 commit d818d158154c5a2a4d7d3817b082d9f7866a3d43 unknown committed Mar 21, 2011
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  1. +6 −0 src/main/scala/lang/TypeParameterization/ExistentialTypes.txt
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6 src/main/scala/lang/TypeParameterization/ExistentialTypes.txt
@@ -29,3 +29,9 @@ the formal theory under the slogan: "Abstract [data] types have existential type
The theory is a second-order typed lambda calculus similar to System F,
but with existential instead of universal quantification.
+existential type An existential type includes references to type variables
+that are unknown. For example, Array[T] forSome { type T } is
+an existential type. It is an array of T, where T is some completely
+unknown type. All that is assumed about T is that it exists at all. This
+assumption is weak, but it means at least that an Array[T] forSome
+{ type T } is indeed an array and not a banana.

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