I read William Cook\'s \"On Data Abstraction, Revisited\", and re-read Ralf Laemmel\'s \"The expression lemma\" to try to understand how to apply the former paper\'s开发者_如何学JAVA ideas in Haskell.
Currently watching Bart De Smet\'s explanation of IQueryable and he mentioned Existential Types (which I\'ve been curious about for some time). After reading the answers to this question I\'m just won
I came across existential quantification over values in the Scala Language Specification (3.2.10 Existential Types).
Code: data Exp a = Const a | Eq (Exp a) (Exp a)开发者_高级运维 I want the Const a to contain a value of type show so that i can print it later. So in C# i would write:
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