避免在Scala中隐式定义歧义 [英] Avoiding implicit def ambiguity in Scala

问题描述

我正在尝试创建从任何类型(例如Int)到字符串的隐式转换...

I am trying to create an implicit conversion from any type (say, Int) to a String...

隐式转换为String意味着RichString方法(如反向)不可用.

An implicit conversion to String means RichString methods (like reverse) are not available.

implicit def intToString(i: Int) = String.valueOf(i)
100.toCharArray  // => Array[Char] = Array(1, 0, 0)
100.reverse // => error: value reverse is not a member of Int
100.length // => 3

对RichString的隐式转换意味着String方法(如toCharArray)不可用

An implicit conversion to RichString means String methods (like toCharArray) are not available

implicit def intToRichString(i: Int) = new RichString(String.valueOf(i))
100.reverse // => "001"
100.toCharArray  // => error: value toCharArray is not a member of Int
100.length // => 3

同时使用两个隐式转换意味着重复的方法(如长度)是不明确的.

Using both implicit conversions means duplicated methods (like length) are ambiguous.

implicit def intToString(i: Int) = String.valueOf(i)
implicit def intToRichString(i: Int) = new RichString(String.valueOf(i))
100.toCharArray  // => Array[Char] = Array(1, 0, 0)
100.reverse // => "001"
100.length // => both method intToString in object $iw of type 
   // (Int)java.lang.String and method intToRichString in object
   // $iw of type (Int)scala.runtime.RichString are possible 
   // conversion functions from Int to ?{val length: ?}

那么，是否可以隐式转换为String并仍然支持所有String和RichString方法?

So, is it possible to implicitly convert to String and still support all String and RichString methods?

推荐答案

要么建立一个庞大的代理类，要么吸纳它，并要求客户端消除歧义:

Either make a huge proxy class, or suck it up and require the client to disambiguate it:

100.asInstanceOf [String] .length

100.asInstanceOf[String].length

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