homework_8 - Бусыгин Никита

homeworks/homework_8/project/build.properties

@@ -1 +1 @@
-sbt.version = 1.3.3
+sbt.version = 1.6.2

homeworks/homework_8/src/main/scala/Exercises.scala

@@ -1,3 +1,34 @@
-import scala.util.Try
+import scala.util.{Success, Try, Failure}
+import scala.util.matching.Regex
+
 object Exercises {
+  trait Read[T] {
+    def read(str: String): Either[String, T]
+  }
+
+  object Read {
+    def read[T](str: String)(implicit read: Read[T]): Either[String, T] = read.read(str)
+  }
+
+  implicit class ReadOps(str: String) {
+    def read[T](implicit read: Read[T]): Either[String, T] = read.read(str)
+  }
+
+  implicit def stringRead: Read[String] = (str: String) => Right(str)
+
+  implicit def intRead: Read[Int] = (str: String) => Try(str.toInt) match {
+    case Success(value) => Right(value)
+    case Failure(_) => Left("Failed to read a number")
+  }
+
+  implicit def optionRead[T: Read]: Read[Option[T]] = {
+    case "None" => Right(None)
+    case str => """Some\((.+)\)""".r.findFirstMatchIn(str) match {
+      case Some(opt) => Read.read[T](opt.group(1)) match {
+        case Right(value) => Right(Some(value))
+        case Left(_) => Left("Failed to read option value")
+      }
+      case None => Left("Incorrect format")
+    }
+  }
 }