commit 21952dc723a275319a82f559aea09814132e5881
Author: JanUlrich <andi@michlaustderaffe.de>
Date:   Wed Sep 29 20:26:49 2021 +0200

    FJ Unify. Step 1. Nicht funktionierendes FC

diff --git a/build.sbt b/build.sbt
new file mode 100644
index 0000000..e69de29
diff --git a/project/build.properties b/project/build.properties
new file mode 100644
index 0000000..dbae93b
--- /dev/null
+++ b/project/build.properties
@@ -0,0 +1 @@
+sbt.version=1.4.9
diff --git a/src/main/scala/hb/dhbw/FiniteClosure.scala b/src/main/scala/hb/dhbw/FiniteClosure.scala
new file mode 100644
index 0000000..ad41ec8
--- /dev/null
+++ b/src/main/scala/hb/dhbw/FiniteClosure.scala
@@ -0,0 +1,85 @@
+package hb.dhbw
+
+
+sealed abstract class Type
+final case class TypeVariable(name : String) extends Type
+final case class RefType(name : String, params : List[Type]) extends Type
+
+class FiniteClosure(val extendsRelations : Set[(RefType, RefType)]){
+
+  def superTypes(of : String) : Set[RefType] = Set(extendsRelations.map(p => (p._1.name, p._2)).toMap.get(of).get)
+  // extendsRelations.filter(p => p._1.name == of).map(p => superTypes(p._1.name)).flatten + extendsRelations.filter(p => p._1.name == of).map(_._1).head
+  def subTypes(of : String) : Set[RefType] =Set(extendsRelations.map(p => (p._1.name, p._2)).toMap.get(of).get)
+    //extendsRelations.filter(p => p._2.name == of).map(p => subTypes(p._2.name)).flatten + extendsRelations.filter(p => p._1.name == of).map(_._1).head
+
+    def getFCType(name : String): RefType ={
+      extendsRelations.map(it => it._1).find(it => it.name == name).get
+    }
+  /*
+
+  def cartesianProduct[A](lists : List[Set[A]]) : Set[List[A]] ={
+
+    def listMultiply[A](inFront: Set[A], list: Set[List[A]]) = list.flatMap(s => inFront.map(element => element :: s))
+
+    if(lists.size == 1) {
+      lists.head.map(it => List(it))
+    }
+    else{
+      listMultiply(lists.head, cartesianProduct(lists.tail))
+    }
+
+  }
+
+    //Kann wiederverwendet werden:
+    def replaceParams(newType : RefType, replace : RefType): RefType ={
+      val fcType = getFCType(replace.name)
+      val replaceMap : Map[TypeVariable, Type] = fcType.params.map{case t: TypePlaceholder => t}.zip(replace.params).toMap
+      RefType(newType.name, newType.params.map{case t: TypePlaceholder => replaceMap(t) case r: RefType => replaceParams(r, replace) })
+    }
+
+    //TODO: Falsche Funktionen
+    def greater(than : SimpleType): Set[SimpleType] = {
+      than match {
+        case RefType(name, params) => {
+          val superTypesNoWildcard = superTypes(name).map(superType => replaceParams(superType, RefType(name, params) ))
+          superTypesNoWildcard
+            .flatMap(superType => {
+              cartesianProduct(superType.params.map(param => greaterArg(param)))
+                .map(parameterList => RefType(superType.name, parameterList))
+            }
+            )
+        }
+        case TypePlaceholder(name) => Set(than)
+      }
+    }
+
+    def smaller(than : SimpleType): Set[SimpleType] = {
+      than match {
+        case RefType(name, params) => {
+          val subTypesNoWildcard = subTypes(name).map(subType => replaceParams(subType, RefType(name, params) ))
+          subTypesNoWildcard
+            .flatMap(subTypes => {
+              cartesianProduct(subTypes.params.map(param => smallerArg(param)))
+                .map(parameterList => RefType(subTypes.name, parameterList))
+            }
+            )
+        }
+        case TypePlaceholder(name) => Set(than)
+      }
+    }
+
+    def greaterArg(t : UnifyType): Set[UnifyType] ={
+      t match { //TODO not recursive yet
+        case RefType(name, params) => Set(t, SuperWildcard(RefType(name, params)), ExtendsWildcard(RefType(name, params)))
+        case other => Set(other)
+      }
+    }
+
+    def smallerArg(t : UnifyType): Set[UnifyType] ={
+      t match { //TODO not recursive yet
+        case RefType(name, params) => Set(t, SuperWildcard(RefType(name, params)), ExtendsWildcard(RefType(name, params)))
+        case other => Set(other)
+      }
+    }
+  */
+}
\ No newline at end of file
diff --git a/src/main/scala/hb/dhbw/Main.scala b/src/main/scala/hb/dhbw/Main.scala
new file mode 100644
index 0000000..879b681
--- /dev/null
+++ b/src/main/scala/hb/dhbw/Main.scala
@@ -0,0 +1,25 @@
+package hb.dhbw
+
+import hb.dhbw.Unify.LessDot
+;
+
+object Main {
+
+  def main(args: Array[String]): Unit = {
+    val fcPair1 = (RefType("ArrayList", List(TypeVariable("A"))), RefType("List", List(TypeVariable("A"))))
+    val fcPair3 = (RefType("List", List(TypeVariable("A"))), RefType("Object", List()))
+    val fcPair2 = (RefType("MyMap", List(TypeVariable("A"), TypeVariable("B"))), RefType("Map", List(RefType("String", List(TypeVariable("A"))), TypeVariable("B"))))
+    val cTest = Set(Set(1,2), Set(4,3))
+    val fc = new FiniteClosure(Set(fcPair1, fcPair2, fcPair3))
+    val cart = Unify.cartesianProduct(cTest)
+    println(cart)
+
+    val step1 = Unify.step1(Set(LessDot(TypeVariable("a"), TypeVariable("b")),
+      LessDot(TypeVariable("a"), RefType("List", List(RefType("Object", List()))))), fc)
+    println(step1)
+    //val replacedType = fc.replaceParams(RefType("List", List(TypePlaceholder("A"))), RefType("ArrayList", List(RefType("String", List()))))
+    //println(replacedType)
+    //val replacedType2 = fc.replaceParams(RefType("Map", List(RefType("String", List(TypePlaceholder("A"))), TypePlaceholder("B"))), RefType("MyMap", List(RefType("String", List()), RefType("Integer", List()))))
+    //println(replacedType2)
+  }
+}
\ No newline at end of file
diff --git a/src/main/scala/hb/dhbw/Unify.scala b/src/main/scala/hb/dhbw/Unify.scala
new file mode 100644
index 0000000..4eb70b2
--- /dev/null
+++ b/src/main/scala/hb/dhbw/Unify.scala
@@ -0,0 +1,51 @@
+package hb.dhbw
+
+
+object Unify {
+
+  sealed abstract class Constraint
+  final case class LessDot(left: Type, right: Type) extends Constraint
+  final case class EqualsDot(left: Type, right: Type) extends Constraint
+
+  def unify(finiteClosure: FiniteClosure): Unit ={
+
+  }
+
+  def step1(eq : Set[Constraint], fc: FiniteClosure) ={
+    val eq1 = eq.filter(c => c match{
+      case LessDot(TypeVariable(_), TypeVariable(_)) => true
+      case EqualsDot(TypeVariable(_), TypeVariable(_)) => true
+      case _ => false
+    })
+    val cLessdotACons: Set[Set[Constraint]] = eq.map(c => c match{
+      case LessDot(RefType(name,params), TypeVariable(a)) =>
+        fc.superTypes(name)
+        .map(superType => EqualsDot(TypeVariable(a), RefType(superType.name, superType.params.map(fc.getFCType(name).params.zip(params).toMap))).asInstanceOf[Constraint])
+      case _ => null
+    }).filter(s => s!=null)
+    //val mutatedCLessdotACons = cartesianProduct(cLessdotACons)
+    val aLessdotCCons: Set[Set[Constraint]] = eq.map(c => c match{
+      case LessDot(TypeVariable(a),RefType(name,params)) =>
+        fc.subTypes(name)
+          .map(subTypes => EqualsDot(TypeVariable(a), RefType(subTypes.name, subTypes.params.map(fc.getFCType(name).params.zip(params).toMap))).asInstanceOf[Constraint])
+      case _ => null
+    }).filter(s => s!=null)
+    //val mutadedALessdotCCons = cartesianProduct(aLessdotCCons)
+    val eqSet = cartesianProduct((Set(Set(eq1))+cLessdotACons+aLessdotCCons).filter(s => !s.isEmpty))
+    eqSet.map( s => s.flatten)
+  }
+
+  def cartesianProduct[A](lists : Set[Set[A]]) : Set[Set[A]] ={
+
+    def listMultiply[A](inFront: Set[A], list: Set[Set[A]]) = list.flatMap(s => inFront.map(element => s + element))
+
+    if(lists.size == 1) {
+      lists.head.map(it => Set(it))
+    }
+    else{
+      listMultiply(lists.head, cartesianProduct(lists.tail))
+    }
+
+  }
+}
+