Scala:如何将`MatchesRegex` 细化与包含反引号(细化库)的正则表达式一起使用? [英] Scala: How to use a `MatchesRegex` refinement with a regex containing a backtick (refined library)?

问题描述

refined 库允许定义与给定 regex 匹配的细化，如Readme所示:

The refined library allows to define refinement that matches a given regex, as shown in the Readme:

import eu.timepit.refined._
import eu.timepit.refined.string._
import eu.timepit.refined.api.Refined

type MyType = String Refined MatchesRegex[W.`"[0-9]+"`.T]

虽然这工作得很好，但我们不能以这种方式定义与包含反引号的正则表达式匹配的类型，因为如此处所述 没有办法在 literal 中转义反引号:

While this works perfectly fine, we can't define this way a type that matches a regex containing a backtick, because as describe here there is no way to escape a backtick within a literal:

 type MyType = String Refined MatchesRegex[W.`"(a|`)"`.T]

 // Getting a compile-error:
 // ']' expected but ')' found.

那么有没有办法定义这样的类型(即 MatchesRegex 与包含反引号的正则表达式)?

So would there be a way to define such a type (i.e MatchesRegex with a regex containing a backtick)?

推荐答案

这样做的方法是使用 单例类型 在 Scala 2.13 或 Typelevel Scala.

A way to do so is to use singleton types available in Scala 2.13 or Typelevel Scala.

对于 Typelevel Scala，您需要在 build.sbt 中添加/替换:

For Typelevel Scala, you need to add / replace in your build.sbt:

scalaOrganization := "org.typelevel",
scalaVersion := "2.12.4-bin-typelevel-4", // Assuming you are using scala 2.12

并且你需要添加编译器标志-Yliteral-types:

And you need to add the compiler flag -Yliteral-types:

scalacOptions := Seq(
                  ..., // Other options
                  "-Yliteral-types"
                 )

现在 refined 类型可以是:

import eu.timepit.refined._
import eu.timepit.refined.api.Refined

type MyType = String Refined MatchesRegex["""(a|`)"""]

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