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package dotty
import scala.annotation.implicitNotFound
@implicitNotFound("No member of type class Show could be found for ${T}")
trait Show[-T] {
def show(t: T): String
}
object Show {
implicit class ShowValue[V](val v: V) extends AnyVal {
def show(implicit ev: Show[V] = null): String =
if (ev != null) ev.show(v)
else v.toString
}
implicit val stringShow = new Show[String] {
//charEscapeSeq ::= ‘\‘ (‘b‘ | ‘t‘ | ‘n‘ | ‘f‘ | ‘r‘ | ‘"‘ | ‘'‘ | ‘\‘)
def show(str: String) =
"\"" +
str
.replaceAll("\b", "\\\\b")
.replaceAll("\t", "\\\\t")
.replaceAll("\n", "\\\\n")
.replaceAll("\f", "\\\\f")
.replaceAll("\r", "\\\\r")
.replaceAll("\'", "\\\\'")
.replaceAll("\"", "\\\\\"") +
"\""
}
implicit val intShow = new Show[Int] {
def show(i: Int) = i.toString
}
implicit val floatShow = new Show[Float] {
def show(f: Float) = f + "f"
}
implicit val doubleShow = new Show[Double] {
def show(d: Double) = d.toString
}
implicit val charShow = new Show[Char] {
def show(c: Char) = "'" + (c match {
case '\b' => "\\b"
case '\t' => "\\t"
case '\n' => "\\n"
case '\f' => "\\f"
case '\r' => "\\r"
case '\'' => "\\'"
case '\"' => "\\\""
case c => c
}) + "'"
}
object List {
implicit def showList[T](implicit st: Show[T]) = new Show[List[T]] {
def show(xs: List[T]) =
if (xs.isEmpty) "Nil"
else "List(" + xs.map(_.show).mkString(", ") + ")"
}
implicit val showNil = new Show[List[Nothing]] {
def show(xs: List[Nothing]) = "Nil"
}
}
object Option {
implicit def showOption[T](implicit st: Show[T]) = new Show[Option[T]] {
def show(ot: Option[T]): String = ot match {
case Some(t) => "Some("+ st.show(t) + ")"
case none => "None"
}
}
implicit val showNone = new Show[Option[Nothing]] {
def show(n: Option[Nothing]) = "None"
}
}
object Map {
implicit def showMap[K, V](implicit sk: Show[K], sv: Show[V]) = new Show[Map[K, V]] {
def show(m: Map[K, V]) =
"Map(" + m.map { case (k, v) => sk.show(k) + " -> " + sv.show(v) } .mkString (", ") + ")"
}
}
}
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