Scala Fun Question 6

This must be a place for the Scala compiler to improve. A person can infer it immediately, and the compiler should be able to infer the

package pz005object pz005 {   def square[t: numeric] (n: t)  = implicitly[numeric[t]].times (n, n)   def twicea[t] (f: t => t, a: t)  = f (f (a))  twiceA ( SQUARE, 2)  //  error not found implicit value   def twiceb[t] (f: t => t) (a: t)  = f (f (a))   twiceb (square) (2)  //  error ibid.   def twicec[t] (a: t,  F: T => T)  = f (f (a))   TWICEC (2, square)  //error Ibid    def twiced[t] (a: t) (f: t => t)  = f (f (a))   twiced (2) ( Square)   // ok,  The compiler detects that 2 is the parameter of type T to be passed to square} 

Square requires an implicit parameter of type numeric[t]

To determine whether the current context has such an implied parameter, you must first identify the type of T

Only the 4th method, "Enough ahead of time" to tell the compiler

Scala Fun topic 6