Simple example: type Expr = | Primitive of int | Addition of (Expr * Expr) | Sub... | Hacker News

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munchler 3 months ago | parent | context | favorite | on: .NET (OK, C#) finally gets union types

Simple example:

   type Expr =
       | Primitive of int
       | Addition of (Expr * Expr)
       | Subtraction of (Expr * Expr)
       | Negation of Expr

Quarrelsome 3 months ago [–]

Isn't that just Func<int> ?

afdbcreid 3 months ago | [–]

Really not. You can, of course, having instead a delegate to evaluate the expression. But then that's all you can do. You can't pretty-print it, for example, or optimize it, or whatever.

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