scala - SBT Output for Kind Type -

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with respect type theory, field of mathematics , computer science both tend use same notation kinds , kinds construction, namely symbols:

  1. *
  2. ->

haskell adopts notation:

prelude> :k maybe maybe :: * -> *

but in sbt, get:

scala> :k option scala.option's kind f[+a]

the haskell way easier understand directly matches literature on type theory. why did sbt not use * , -> notation? information can see being imparted sbt way type variance.

try verbose flag (-v)

scala> :k -v option scala.option's kind f[+a] * -(+)-> * type constructor: 1st-order-kinded type.

some more info:

http://docs.scala-lang.org/scala/2.11/ (ctrl+f :kind)

https://github.com/scala/scala/pull/2340


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