Import funsets handout

.vscode/settings.json

@@ -0,0 +1,8 @@
+{
+  "dotty": {
+    "trace": {
+      "remoteTracingUrl": "wss://lamppc36.epfl.ch/dotty-remote-tracer/upload/lsp.log",
+      "server": { "format": "JSON", "verbosity": "verbose" }
+    }
+  }
+}

build.sbt

@@ -0,0 +1,12 @@
+course := "progfun1"
+assignment := "funsets"
+name := course.value + "-" + assignment.value
+testSuite := "funsets.FunSetSuite"
+
+scalaVersion := "0.19.0-bin-20190918-dd68eb8-NIGHTLY"
+
+scalacOptions ++= Seq("-language:implicitConversions", "-deprecation")
+
+libraryDependencies += "com.novocode" % "junit-interface" % "0.11" % Test
+
+testOptions in Test += Tests.Argument(TestFrameworks.JUnit, "-a", "-v", "-s")

project/MOOCSettings.scala

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+package ch.epfl.lamp
+
+import sbt._
+import sbt.Keys._
+
+/**
+  * Settings shared by all assignments, reused in various tasks.
+  */
+object MOOCSettings extends AutoPlugin {
+
+  object autoImport {
+    val course = SettingKey[String]("course")
+    val assignment = SettingKey[String]("assignment")
+    val testSuite = SettingKey[String]("testSuite")
+    val options = SettingKey[Map[String, Map[String, String]]]("options")
+  }
+
+  override def trigger = allRequirements
+
+  override val projectSettings: Seq[Def.Setting[_]] = Seq(
+    parallelExecution in Test := false
+  )
+}

project/StudentTasks.scala

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+package ch.epfl.lamp
+
+import sbt._
+import Keys._
+
+// import scalaj.http._
+import java.io.{File, FileInputStream, IOException}
+import java.nio.file.FileSystems
+import org.apache.commons.codec.binary.Base64
+// import play.api.libs.json.{Json, JsObject, JsPath}
+import scala.util.{Failure, Success, Try}
+
+import MOOCSettings.autoImport._
+
+case class AssignmentInfo(
+  key: String,
+  itemId: String,
+  premiumItemId: Option[String],
+  partId: String
+)
+
+/**
+  * Provides tasks for submitting the assignment
+  */
+object StudentTasks extends AutoPlugin {
+
+  object autoImport {
+    val assignmentInfo = SettingKey[AssignmentInfo]("assignmentInfo")
+
+    val packageSourcesOnly = TaskKey[File]("packageSourcesOnly", "Package the sources of the project")
+    val packageBinWithoutResources = TaskKey[File]("packageBinWithoutResources", "Like packageBin, but without the resources")
+    val packageSubmissionZip = TaskKey[File]("packageSubmissionZip")
+    val packageSubmission = inputKey[Unit]("package solution as an archive file")
+    val runGradingTests = taskKey[Unit]("run black-box tests used for final grading")
+  }
+
+
+  import autoImport._
+
+  override lazy val projectSettings = Seq(
+    packageSubmissionSetting,
+    // submitSetting, // FIXME: restore assignmentInfo setting on assignments
+    runGradingTestsSettings,
+
+    fork := true,
+    connectInput in run := true,
+    outputStrategy := Some(StdoutOutput)
+  ) ++ packageSubmissionZipSettings
+
+  lazy val runGradingTestsSettings = runGradingTests := {
+    val testSuiteJar = "grading-tests.jar"
+    if (!new File(testSuiteJar).exists) {
+      throw new MessageOnlyException(s"Could not find tests JarFile: $testSuiteJar")
+    }
+
+    val classPath = s"${(Test / dependencyClasspath).value.map(_.data).mkString(File.pathSeparator)}${File.pathSeparator}$testSuiteJar"
+    val junitProcess =
+      Fork.java.fork(
+        ForkOptions(),
+        "-cp" :: classPath ::
+        "org.junit.runner.JUnitCore" ::
+        (Test / testSuite).value ::
+        Nil
+      )
+
+    // Wait for tests to complete.
+    junitProcess.exitValue()
+  }
+
+
+  /** **********************************************************
+    * SUBMITTING A SOLUTION TO COURSERA
+    */
+
+  val packageSubmissionZipSettings = Seq(
+    packageSubmissionZip := {
+      val submission = crossTarget.value / "submission.zip"
+      val sources = (packageSourcesOnly in Compile).value
+      val binaries = (packageBinWithoutResources in Compile).value
+      IO.zip(Seq(sources -> "sources.zip", binaries -> "binaries.jar"), submission)
+      submission
+    },
+    artifactClassifier in packageSourcesOnly := Some("sources"),
+    artifact in (Compile, packageBinWithoutResources) ~= (art => art.withName(art.name + "-without-resources"))
+  ) ++
+  inConfig(Compile)(
+    Defaults.packageTaskSettings(packageSourcesOnly, Defaults.sourceMappings) ++
+    Defaults.packageTaskSettings(packageBinWithoutResources, Def.task {
+      val relativePaths =
+        (unmanagedResources in Compile).value.flatMap(Path.relativeTo((unmanagedResourceDirectories in Compile).value)(_))
+      (mappings in (Compile, packageBin)).value.filterNot { case (_, path) => relativePaths.contains(path) }
+    })
+  )
+
+  val maxSubmitFileSize = {
+    val mb = 1024 * 1024
+    10 * mb
+  }
+
+  /** Check that the jar exists, isn't empty, isn't crazy big, and can be read
+    * If so, encode jar as base64 so we can send it to Coursera
+    */
+  def prepareJar(jar: File, s: TaskStreams): String = {
+    val errPrefix = "Error submitting assignment jar: "
+    val fileLength = jar.length()
+    if (!jar.exists()) {
+      s.log.error(errPrefix + "jar archive does not exist\n" + jar.getAbsolutePath)
+      failSubmit()
+    } else if (fileLength == 0L) {
+      s.log.error(errPrefix + "jar archive is empty\n" + jar.getAbsolutePath)
+      failSubmit()
+    } else if (fileLength > maxSubmitFileSize) {
+      s.log.error(errPrefix + "jar archive is too big. Allowed size: " +
+        maxSubmitFileSize + " bytes, found " + fileLength + " bytes.\n" +
+        jar.getAbsolutePath)
+      failSubmit()
+    } else {
+      val bytes = new Array[Byte](fileLength.toInt)
+      val sizeRead = try {
+        val is = new FileInputStream(jar)
+        val read = is.read(bytes)
+        is.close()
+        read
+      } catch {
+        case ex: IOException =>
+          s.log.error(errPrefix + "failed to read sources jar archive\n" + ex.toString)
+          failSubmit()
+      }
+      if (sizeRead != bytes.length) {
+        s.log.error(errPrefix + "failed to read the sources jar archive, size read: " + sizeRead)
+        failSubmit()
+      } else encodeBase64(bytes)
+    }
+  }
+
+  /** Task to package solution to a given file path */
+  lazy val packageSubmissionSetting = packageSubmission := {
+    val args: Seq[String] = Def.spaceDelimited("[path]").parsed
+    val s: TaskStreams = streams.value // for logging
+    val jar = (packageSubmissionZip in Compile).value
+
+    val base64Jar = prepareJar(jar, s)
+
+    val path = args.headOption.getOrElse((baseDirectory.value / "submission.jar").absolutePath)
+    scala.tools.nsc.io.File(path).writeAll(base64Jar)
+  }
+
+/*
+  /** Task to submit a solution to coursera */
+  val submit = inputKey[Unit]("submit solution to Coursera")
+  lazy val submitSetting = submit := {
+    val args: Seq[String] = Def.spaceDelimited("<arg>").parsed
+    val s: TaskStreams = streams.value // for logging
+    val jar = (packageSubmissionZip in Compile).value
+
+    val assignmentDetails = assignmentInfo.value
+    val assignmentKey = assignmentDetails.key
+    val courseName =
+      course.value match {
+        case "capstone" => "scala-capstone"
+        case "bigdata"  => "scala-spark-big-data"
+        case other      => other
+      }
+
+    val partId = assignmentDetails.partId
+    val itemId = assignmentDetails.itemId
+    val premiumItemId = assignmentDetails.premiumItemId
+
+    val (email, secret) = args match {
+      case email :: secret :: Nil =>
+        (email, secret)
+      case _ =>
+        val inputErr =
+          s"""|Invalid input to `submit`. The required syntax for `submit` is:
+              |submit <email-address> <submit-token>
+              |
+              |The submit token is NOT YOUR LOGIN PASSWORD.
+              |It can be obtained from the assignment page:
+              |https://www.coursera.org/learn/$courseName/programming/$itemId
+              |${
+                premiumItemId.fold("") { id =>
+                  s"""or (for premium learners):
+                     |https://www.coursera.org/learn/$courseName/programming/$id
+                   """.stripMargin
+                }
+              }
+          """.stripMargin
+        s.log.error(inputErr)
+        failSubmit()
+    }
+
+    val base64Jar = prepareJar(jar, s)
+    val json =
+      s"""|{
+          |   "assignmentKey":"$assignmentKey",
+          |   "submitterEmail":"$email",
+          |   "secret":"$secret",
+          |   "parts":{
+          |      "$partId":{
+          |         "output":"$base64Jar"
+          |      }
+          |   }
+          |}""".stripMargin
+
+    def postSubmission[T](data: String): Try[HttpResponse[String]] = {
+      val http = Http("https://www.coursera.org/api/onDemandProgrammingScriptSubmissions.v1")
+      val hs = List(
+        ("Cache-Control", "no-cache"),
+        ("Content-Type", "application/json")
+      )
+      s.log.info("Connecting to Coursera...")
+      val response = Try(http.postData(data)
+                         .headers(hs)
+                         .option(HttpOptions.connTimeout(10000)) // scalaj default timeout is only 100ms, changing that to 10s
+                         .asString) // kick off HTTP POST
+      response
+    }
+
+    val connectMsg =
+      s"""|Attempting to submit "${assignment.value}" assignment in "$courseName" course
+          |Using:
+          |- email: $email
+          |- submit token: $secret""".stripMargin
+    s.log.info(connectMsg)
+
+    def reportCourseraResponse(response: HttpResponse[String]): Unit = {
+      val code = response.code
+      val respBody = response.body
+
+       /* Sample JSON response from Coursera
+      {
+        "message": "Invalid email or token.",
+        "details": {
+          "learnerMessage": "Invalid email or token."
+        }
+      }
+      */
+
+      // Success, Coursera responds with 2xx HTTP status code
+      if (response.is2xx) {
+        val successfulSubmitMsg =
+          s"""|Successfully connected to Coursera. (Status $code)
+              |
+                |Assignment submitted successfully!
+              |
+                |You can see how you scored by going to:
+              |https://www.coursera.org/learn/$courseName/programming/$itemId/
+              |${
+            premiumItemId.fold("") { id =>
+              s"""or (for premium learners):
+                 |https://www.coursera.org/learn/$courseName/programming/$id
+                       """.stripMargin
+            }
+          }
+              |and clicking on "My Submission".""".stripMargin
+        s.log.info(successfulSubmitMsg)
+      }
+
+      // Failure, Coursera responds with 4xx HTTP status code (client-side failure)
+      else if (response.is4xx) {
+        val result = Try(Json.parse(respBody)).toOption
+        val learnerMsg = result match {
+          case Some(resp: JsObject) =>
+            (JsPath \ "details" \ "learnerMessage").read[String].reads(resp).get
+          case Some(x) => // shouldn't happen
+            "Could not parse Coursera's response:\n" + x
+          case None =>
+            "Could not parse Coursera's response:\n" + respBody
+        }
+        val failedSubmitMsg =
+          s"""|Submission failed.
+              |There was something wrong while attempting to submit.
+              |Coursera says:
+              |$learnerMsg (Status $code)""".stripMargin
+        s.log.error(failedSubmitMsg)
+      }
+
+      // Failure, Coursera responds with 5xx HTTP status code (server-side failure)
+      else if (response.is5xx) {
+        val failedSubmitMsg =
+          s"""|Submission failed.
+              |Coursera seems to be unavailable at the moment (Status $code)
+              |Check https://status.coursera.org/ and try again in a few minutes.
+           """.stripMargin
+        s.log.error(failedSubmitMsg)
+      }
+
+      // Failure, Coursera repsonds with an unexpected status code
+      else {
+        val failedSubmitMsg =
+          s"""|Submission failed.
+              |Coursera replied with an unexpected code (Status $code)
+           """.stripMargin
+        s.log.error(failedSubmitMsg)
+      }
+    }
+
+    // kick it all off, actually make request
+    postSubmission(json) match {
+      case Success(resp) => reportCourseraResponse(resp)
+      case Failure(e) =>
+        val failedConnectMsg =
+          s"""|Connection to Coursera failed.
+              |There was something wrong while attempting to connect to Coursera.
+              |Check your internet connection.
+              |${e.toString}""".stripMargin
+        s.log.error(failedConnectMsg)
+    }
+
+   }
+*/
+
+  def failSubmit(): Nothing = {
+    sys.error("Submission failed")
+  }
+
+  /**
+    * *****************
+    * DEALING WITH JARS
+    */
+  def encodeBase64(bytes: Array[Byte]): String =
+    new String(Base64.encodeBase64(bytes))
+}

project/build.properties

@@ -0,0 +1 @@
+sbt.version=1.2.8

project/buildSettings.sbt

@@ -0,0 +1,8 @@
+libraryDependencies += "com.novocode" % "junit-interface" % "0.11" % Test
+// Used for base64 encoding
+libraryDependencies += "commons-codec" % "commons-codec" % "1.10"
+
+// Used for Coursera submussion
+// libraryDependencies += "org.scalaj" %% "scalaj-http" % "2.3.0"
+// libraryDependencies += "com.typesafe.play" %% "play-json" % "2.6.9"
+

project/plugins.sbt

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+addSbtPlugin("io.get-coursier" % "sbt-coursier" % "2.0.0-RC3-5")
+addSbtPlugin("ch.epfl.lamp" % "sbt-dotty" % "0.3.4")

src/main/scala/funsets/FunSets.scala

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+package funsets
+
+/**
+ * 2. Purely Functional Sets.
+ */
+trait FunSets extends FunSetsInterface {
+  /**
+   * We represent a set by its characteristic function, i.e.
+   * its `contains` predicate.
+   */
+  override type FunSet = Int => Boolean
+
+  /**
+   * Indicates whether a set contains a given element.
+   */
+  def contains(s: FunSet, elem: Int): Boolean = s(elem)
+
+  /**
+   * Returns the set of the one given element.
+   */
+  def singletonSet(elem: Int): FunSet = ???
+
+
+  /**
+   * Returns the union of the two given sets,
+   * the sets of all elements that are in either `s` or `t`.
+   */
+  def union(s: FunSet, t: FunSet): FunSet = ???
+
+  /**
+   * Returns the intersection of the two given sets,
+   * the set of all elements that are both in `s` and `t`.
+   */
+  def intersect(s: FunSet, t: FunSet): FunSet = ???
+
+  /**
+   * Returns the difference of the two given sets,
+   * the set of all elements of `s` that are not in `t`.
+   */
+  def diff(s: FunSet, t: FunSet): FunSet = ???
+
+  /**
+   * Returns the subset of `s` for which `p` holds.
+   */
+  def filter(s: FunSet, p: Int => Boolean): FunSet = ???
+
+
+  /**
+   * The bounds for `forall` and `exists` are +/- 1000.
+   */
+  val bound = 1000
+
+  /**
+   * Returns whether all bounded integers within `s` satisfy `p`.
+   */
+  def forall(s: FunSet, p: Int => Boolean): Boolean =
+    def iter(a: Int): Boolean =
+      if ??? then
+        ???
+      else if ??? then
+        ???
+      else
+        iter(???)
+    iter(???)
+
+  /**
+   * Returns whether there exists a bounded integer within `s`
+   * that satisfies `p`.
+   */
+  def exists(s: FunSet, p: Int => Boolean): Boolean = ???
+
+  /**
+   * Returns a set transformed by applying `f` to each element of `s`.
+   */
+  def map(s: FunSet, f: Int => Int): FunSet = ???
+
+  /**
+   * Displays the contents of a set
+   */
+  def toString(s: FunSet): String =
+    val xs = for i <- (-bound to bound) if contains(s, i) yield i
+    xs.mkString("{", ",", "}")
+
+  /**
+   * Prints the contents of a set on the console.
+   */
+  def printSet(s: FunSet): Unit =
+    println(toString(s))
+}
+
+object FunSets extends FunSets

src/main/scala/funsets/FunSetsInterface.scala

@@ -0,0 +1,20 @@
+package funsets
+
+/**
+ * The interface used by the grading infrastructure. You should not edit any
+ * code here, or your submission may fail with a NoSuchMethodError.
+ */
+trait FunSetsInterface {
+  type FunSet = Int => Boolean
+
+  def contains(s: FunSet, elem: Int): Boolean
+  def singletonSet(elem: Int): FunSet
+  def union(s: FunSet, t: FunSet): FunSet
+  def intersect(s: FunSet, t: Int => Boolean): FunSet
+  def diff(s: FunSet, t: FunSet): FunSet
+  def filter(s: FunSet, p: Int => Boolean): FunSet
+  def forall(s: FunSet, p: Int => Boolean): Boolean
+  def exists(s: FunSet, p: Int => Boolean): Boolean
+  def map(s: FunSet, f: Int => Int): FunSet
+  def toString(s: FunSet): String
+}

src/main/scala/funsets/Main.scala

@@ -0,0 +1,6 @@
+package funsets
+
+object Main extends App {
+  import FunSets._
+  println(contains(singletonSet(1), 1))
+}

src/test/scala/funsets/FunSetSuite.scala

@@ -0,0 +1,73 @@
+package funsets
+
+import org.junit._
+
+/**
+ * This class is a test suite for the methods in object FunSets.
+ *
+ * To run this test suite, start "sbt" then run the "test" command.
+ */
+class FunSetSuite {
+
+  import FunSets._
+
+  @Test def `contains is implemented`: Unit =
+    assert(contains(x => true, 100))
+
+  /**
+   * When writing tests, one would often like to re-use certain values for multiple
+   * tests. For instance, we would like to create an Int-set and have multiple test
+   * about it.
+   *
+   * Instead of copy-pasting the code for creating the set into every test, we can
+   * store it in the test class using a val:
+   *
+   *   val s1 = singletonSet(1)
+   *
+   * However, what happens if the method "singletonSet" has a bug and crashes? Then
+   * the test methods are not even executed, because creating an instance of the
+   * test class fails!
+   *
+   * Therefore, we put the shared values into a separate trait (traits are like
+   * abstract classes), and create an instance inside each test method.
+   *
+   */
+
+  trait TestSets {
+    val s1 = singletonSet(1)
+    val s2 = singletonSet(2)
+    val s3 = singletonSet(3)
+  }
+
+  /**
+   * This test is currently disabled (by using @Ignore) because the method
+   * "singletonSet" is not yet implemented and the test would fail.
+   *
+   * Once you finish your implementation of "singletonSet", remvoe the
+   * @Ignore annotation.
+   */
+  @Ignore("not ready yet") @Test def `singleton set one contains one`: Unit =
+    /**
+     * We create a new instance of the "TestSets" trait, this gives us access
+     * to the values "s1" to "s3".
+     */
+    new TestSets {
+      /**
+       * The string argument of "assert" is a message that is printed in case
+       * the test fails. This helps identifying which assertion failed.
+       */
+      assert(contains(s1, 1), "Singleton")
+    }
+
+  @Test def `union contains all elements of each set`: Unit =
+    new TestSets {
+      val s = union(s1, s2)
+      assert(contains(s, 1), "Union 1")
+      assert(contains(s, 2), "Union 2")
+      assert(!contains(s, 3), "Union 3")
+    }
+
+
+
+  @Rule def individualTestTimeout = new org.junit.rules.Timeout(10 * 1000)
+}

student.sbt

@@ -0,0 +1,9 @@
+// Used for base64 encoding
+libraryDependencies += "commons-codec" % "commons-codec" % "1.10"
+
+// Used for Coursera submussion
+// libraryDependencies += "org.scalaj" %% "scalaj-http" % "2.4.2"
+// libraryDependencies += "com.typesafe.play" %% "play-json" % "2.7.4"
+
+// Student tasks (i.e. packageSubmission)
+enablePlugins(StudentTasks)