Scala：方便绑定集合类型参数
为了方便、清晰和抽象，我想为参数化集合特征的特定绑定指定另一个名称。例如，首先考虑：
import collection.mutable.Map // NB: Map is a trait
val m1 = Map[String, Int]() // uses the Map companion object to create a HashMap
现在我想用 MyMap 替换 Map[String, Int]。理想情况下，我只想做类似的事情：
trait MyMap extends Map[String, Int]
object MyMap extends Map[String, Int] // not good enough by itself, need some apply defs
val m2 = MyMap() // nope
我可以向 MyMap 伴随对象添加更多内容，或者我可以使 MyMap 扩展 HashMap[String, Int] 并忘记依赖于 Map 伴随对象内部的默认魔法。
但这些替代方案对于应该很简单的事情来说似乎太多了：我只想 MyMap 无论出现在哪里，都可以像 Map[String, Int] 一样工作。最简单的方法是什么，还是我错过了一些更深层次的原则？
For convenience, clarity, and abstraction, I want to make up another name for a specific binding of a parameterized collection trait. For instance, first consider:
import collection.mutable.Map // NB: Map is a trait
val m1 = Map[String, Int]() // uses the Map companion object to create a HashMap
Now I want to substitute MyMap for Map[String, Int]. Ideally I would just like to do something like:
trait MyMap extends Map[String, Int]
object MyMap extends Map[String, Int] // not good enough by itself, need some apply defs
val m2 = MyMap() // nope
I could add more stuff to the MyMap companion object, or I could make MyMap extend HashMap[String, Int] and forget about relying on the magic defaulting inside the Map companion object.
But those alternatives seem like too much work for something that should be simple: I just want MyMap to act like Map[String, Int] wherever it appears. What's the easiest way to do that, or am I missing some deeper principle?
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使用类型别名：
请注意，这不会为您提供
object MyMap，并且如果您定义了它，它不是伴随对象（object Map> 是）并且编译器不会检查它的隐式转换。Use a type alias:
Note this won't give you
object MyMap, and if you define it, it is not the companion object (object Mapis) and the compiler won't check it for implicit conversions.@阿列克谢·罗曼诺夫
类型别名不会为您提供工厂方法。另一方面，进口会。
@Alexey Romanov
A type alias won't give you the factory method. An import on the other hand will.