你能在 Scala 中使用自定义字符串插值字符吗？

Question

Scala 的 string interpolation 使用起来非常简单：

val user = "Bob"
val message = s"Hello, $user"
//Hello, Bob

对于包含大量财务数据的字符串块，这些通常需要双重转义，但是（对于大块，例如测试数据，可能会变长）：

val user = "Mary"
val message = s"Balance owing for $user is 0"
//error: invalid string interpolation , expected: $$, $identifier or ${expression}
//error: unclosed string literal
val message = s"Balance owing for $user is $0"
//Balance owing for Mary is 0

是否可以使用不同的插值字符来避免双重转义？

val characterA = "Randolph"
val characterB = "Mortimer"
val family = "Duke"
val film = "Trading Places"
val outcome = "wagered"
val message = at"Your property was @{outcome} for  by brothers @{characterA} and @{characterB} @{family}"
//Your property was wagered for  by brothers Randolph and Mortimer Duke

Answer 1

您可以随时使用 format 方法：

val message = "Your property was %s for 1$ by brothers %s and %s %s"
println(message.format("actual outcome", "actual characterA", "actual characterB", "actual family"))

Answer 2

Is it possible to use a different interpolation character to avoid the double escape?

$ 是 Scala syntax, however it is at least possible to define custom string interpolation 的一部分

scala> implicit class DollarSignInterpolation(val sc: StringContext) {
     |   def usd(args: Any*): String =
     |     sc.s(args:_*).replace("USD", "$")
     | }
class DollarSignInterpolation

scala> val user = "Mary"
val user: String = Mary

scala> usd"""Balance owing for $user is USD100"""
val res0: String = Balance owing for Mary is 0

你能在 Scala 中使用自定义字符串插值字符吗？

Can you use a custom string interpolation character in Scala?

string

interpolation

scala

string-interpolation