如何取消导入字符串“+"Scala 中的运算符? [英] How to unimport String "+" operator in Scala?

问题描述

我正在编写一个 DSL，其中+"运算符是严格的数字，就像其他一些流行语言一样.它很接近，但是字符串+"运算符弄乱了我的隐式转换.取消导入 String 类的运算符的语法是什么?

为了更清楚，而不是这样:

<前>Scala> var x = "2" + 3;x: java.lang.String = 23

我想得到 x: Int = 5

我想我只需要两件事就可以做到这一点:

• 从字符串中删除(在我的范围内取消导入)+"的定义
• 定义 String 到 Int 的隐式转换

我被困在第一步.

谢谢

解决方案

根据 Scala 规范，String 的 + 方法被编译器特殊处理.我不确定，但我认为这意味着您不能取消导入"它，这是一种耻辱，因为它确实破坏了类型系统(很像相关的 toString 方法).

您能否在 DSL 中为运算符使用不同的名称，例如 ++ 或 &?

I'm writing a DSL where the "+" operator is strictly numeric, like some other popular languages. It's close, but the String "+" operator is messing up my implicit conversions. What's the syntax for unimporting an operator of the String class?

Just to be clearer, instead of this:

scala> var x = "2" + 3;
x: java.lang.String = 23

I'd like to get x: Int = 5

I imagine I just need 2 things to make that happen:

• Remove (unimport within my scope) the definition of "+" from Strings
• Define an implicit conversion of String to Int

I'm stuck on the first step.

Thanks

解决方案

According to section 12.3.1 of the Scala spec, the + method for String has special treatment by the compiler. I don't know for sure, but I think this means you can't "unimport" it, which is a shame because it really breaks the type system (much like the related toString method).

Could you use a different name for the operator in your DSL, eg, ++ or &?

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