Comments on: Partially Applying Scala type variables http://blog.tmorris.net/partially-applying-scala-type-variables/ The weblog of Tony Morris Tue, 07 Feb 2012 18:26:14 +0000 http://wordpress.org/?v=2.6 By: Tony Morris http://blog.tmorris.net/partially-applying-scala-type-variables/#comment-16253 Tony Morris Tue, 23 Sep 2008 01:12:25 +0000 http://blog.tmorris.net/?p=337#comment-16253 Hi Channing, that is a type variable of a higher kind. It means you can pass in a <em>type constructor</em> that matches that kind. The kind being, that it takes one more type argument. For example, you can use <code>List</code> because it takes one more type argument, but you couldn't use <code>String</code>, <code>Int</code>, <code>Either</code> or <code>List[Int]</code> as the type value for M[_] since they don't accept one (and only one) type variable. I hope this helps ;) Hi Channing, that is a type variable of a higher kind. It means you can pass in a type constructor that matches that kind. The kind being, that it takes one more type argument. For example, you can use List because it takes one more type argument, but you couldn’t use String, Int, Either or List[Int] as the type value for M[_] since they don’t accept one (and only one) type variable.

I hope this helps ;)

]]> By: Channing Walton http://blog.tmorris.net/partially-applying-scala-type-variables/#comment-16239 Channing Walton Mon, 22 Sep 2008 18:08:50 +0000 http://blog.tmorris.net/?p=337#comment-16239 Hi Tony, can you explain what M[_] means? Thanks. Channing Hi Tony,
can you explain what M[_] means?

Thanks.

Channing

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