为什么Scala和C＃lambdas的双箭头？

Question

Does anyone know some background, why Scala and C# use double arrow (=>) for lambdas instead of single arrow (->)?

Single arrow is more common in literature, is used in Haskell, O'Caml, F#, Groovy etc. and IMO it also looks nicer :)

Answer 1

在C＃中，可能是因为->运算符已用于不安全代码（LINK）

Answer 2

Pizza, which was sort of a predecessor for Scala had -> in function types. I remember that C++ programmers were baffled by this choice of symbol. That's the primary reason why Scala chose => AFAIRC. It seems the C# guys went through the same reasoning.

Answer 3

In Scala, there is also the "map arrow" that indicates a mapping from an item a to another b . Using => for lambdas frees up -> for things like Map(1 -> "One", 2 -> "Two") , and as others have pointed out the => is not unique to C# and Scala.

Answer 4

您可能有兴趣知道在Scala中您可以使用=>的unicode以及其他箭头： http ： //scala-programming-language.1934581.n4.nabble.com/More-unicode-alternatives-for- ASCII运营商，td2008146.html