diff --git a/pom.xml b/pom.xml
index 0347720..2eee15b 100644
--- a/pom.xml
+++ b/pom.xml
@@ -8,9 +8,18 @@
   <artifactId>transcendental-lisp</artifactId>
   <version>1.2.1</version>
 
+  <!-- TODO - remove after kotlin 1.3 is released -->
+  <repositories>
+    <repository>
+      <id>kotlin-eap</id>
+      <name>Kotlin EAP</name>
+      <url>https://dl.bintray.com/kotlin/kotlin-eap</url>
+    </repository>
+  </repositories>
+
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <kotlin.version>1.2.71</kotlin.version>
+    <kotlin.version>1.3.0-rc-190</kotlin.version>
     <junit5.version>5.3.1</junit5.version>
     <skipTests>false</skipTests>
   </properties>
diff --git a/src/main/kotlin/function/builtin/special/CASE.java b/src/main/kotlin/function/builtin/special/CASE.java
deleted file mode 100644
index df994d2..0000000
--- a/src/main/kotlin/function/builtin/special/CASE.java
+++ /dev/null
@@ -1,84 +0,0 @@
-package function.builtin.special;
-
-import function.ArgumentValidator;
-import function.FunctionNames;
-import function.LispSpecialFunction;
-import recursion.TailCall;
-import sexpression.Cons;
-import sexpression.Nil;
-import sexpression.SExpression;
-import sexpression.Symbol;
-
-import static function.builtin.Eval.eval;
-import static function.builtin.predicate.EQUAL.isEqual;
-import static recursion.TailCalls.done;
-import static recursion.TailCalls.tailCall;
-
-@FunctionNames({ "CASE" })
-public class CASE extends LispSpecialFunction {
-
-    private ArgumentValidator argumentValidator;
-
-    public CASE(String name) {
-        this.argumentValidator = new ArgumentValidator(name);
-        this.argumentValidator.setMinimumNumberOfArguments(1);
-        this.argumentValidator.setTrailingArgumentExpectedType(Cons.class);
-        this.argumentValidator.setTrailingArgumentExcludedType(Nil.class);
-    }
-
-    @Override
-    public SExpression call(Cons argumentList) {
-        argumentValidator.validate(argumentList);
-        SExpression key = eval(argumentList.getFirst());
-
-        return callTailRecursive(key, (Cons) argumentList.getRest()).invoke();
-    }
-
-    private TailCall<SExpression> callTailRecursive(SExpression key, Cons argumentList) {
-        if (argumentList.isNull())
-            return done(Nil.INSTANCE);
-
-        Cons clause = (Cons) argumentList.getFirst();
-        Cons remainingClauses = (Cons) argumentList.getRest();
-        SExpression keyList = clause.getFirst();
-
-        if (isMatch(key, keyList))
-            return done(evaluateConsequents(clause.getRest()));
-
-        return tailCall(() -> callTailRecursive(key, remainingClauses));
-    }
-
-    private boolean isMatch(SExpression key, SExpression keyList) {
-        if (keyList.isNull())
-            return false;
-        else if (keyList.isCons())
-            return containsMatch(key, keyList);
-
-        return isEqual(key, keyList) || isEqual(Symbol.Companion.getT(), keyList);
-    }
-
-    private boolean containsMatch(SExpression key, SExpression keyList) {
-        for (; keyList.isCons(); keyList = advanceCons(keyList))
-            if (isEqual(key, getFirst(keyList)))
-                return true;
-
-        return false;
-    }
-
-    private SExpression advanceCons(SExpression knownCons) {
-        return ((Cons) knownCons).getRest();
-    }
-
-    private SExpression getFirst(SExpression knownCons) {
-        return ((Cons) knownCons).getFirst();
-    }
-
-    private SExpression evaluateConsequents(SExpression consequentList) {
-        SExpression lastConsequentValue = Nil.INSTANCE;
-
-        for (; consequentList.isCons(); consequentList = advanceCons(consequentList))
-            lastConsequentValue = eval(getFirst(consequentList));
-
-        return lastConsequentValue;
-    }
-}
diff --git a/src/main/kotlin/function/builtin/special/Case.kt b/src/main/kotlin/function/builtin/special/Case.kt
new file mode 100644
index 0000000..db65fa6
--- /dev/null
+++ b/src/main/kotlin/function/builtin/special/Case.kt
@@ -0,0 +1,72 @@
+package function.builtin.special
+
+import function.ArgumentValidator
+import function.FunctionNames
+import function.LispSpecialFunction
+import function.builtin.Eval.Companion.eval
+import function.builtin.predicate.EQUAL.isEqual
+import sexpression.Cons
+import sexpression.Nil
+import sexpression.SExpression
+import sexpression.Symbol
+
+@FunctionNames("CASE")
+class Case(name: String) : LispSpecialFunction() {
+
+    private val argumentValidator = ArgumentValidator(name).apply {
+        setMinimumNumberOfArguments(1)
+        setTrailingArgumentExpectedType(Cons::class.java)
+        setTrailingArgumentExcludedType(Nil::class.java)
+    }
+
+    override fun call(argumentList: Cons): SExpression {
+        argumentValidator.validate(argumentList)
+        val key = eval(argumentList.first)
+
+        return callTailRecursive(key, argumentList.rest as Cons)
+    }
+
+    private tailrec fun callTailRecursive(key: SExpression, argumentList: Cons): SExpression {
+        if (argumentList.isNull)
+            return Nil
+
+        val clause = argumentList.first as Cons
+        val remainingClauses = argumentList.rest as Cons
+        val keyList = clause.first
+
+        return if (isMatch(key, keyList))
+            evaluateConsequents(clause.rest)
+        else
+            callTailRecursive(key, remainingClauses)
+    }
+
+    private fun isMatch(key: SExpression, keyList: SExpression) = when {
+        keyList.isNull -> false
+        keyList.isCons -> containsMatch(key, keyList)
+        else           -> isEqual(key, keyList) || isEqual(Symbol.T, keyList)
+    }
+
+    private fun containsMatch(key: SExpression, keyList: SExpression): Boolean {
+        if (keyList.isCons) {
+            (keyList as Cons).forEach {
+                if (isEqual(key, it.first)) {
+                    return true
+                }
+            }
+        }
+
+        return false
+    }
+
+    private fun evaluateConsequents(consequentList: SExpression): SExpression {
+        var lastConsequentValue: SExpression = Nil
+
+        if (consequentList.isCons) {
+            (consequentList as Cons).forEach {
+                lastConsequentValue = eval(it.first)
+            }
+        }
+
+        return lastConsequentValue
+    }
+}
diff --git a/src/test/kotlin/function/builtin/special/CASETest.java b/src/test/kotlin/function/builtin/special/CASETest.java
deleted file mode 100644
index a113d97..0000000
--- a/src/test/kotlin/function/builtin/special/CASETest.java
+++ /dev/null
@@ -1,196 +0,0 @@
-package function.builtin.special;
-
-import function.ArgumentValidator.BadArgumentTypeException;
-import function.ArgumentValidator.TooFewArgumentsException;
-import org.junit.Test;
-import testutil.SymbolAndFunctionCleaner;
-
-import static testutil.TestUtilities.assertSExpressionsMatch;
-import static testutil.TestUtilities.evaluateString;
-import static testutil.TestUtilities.parseString;
-
-public class CASETest extends SymbolAndFunctionCleaner {
-
-    @Test
-    public void caseWithKeyOnly() {
-        String input = "(case t)";
-
-        assertSExpressionsMatch(parseString("nil"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithEmptyConsequent() {
-        String input = "(case :a ((:a)))";
-
-        assertSExpressionsMatch(parseString("nil"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithOneClause_Match() {
-        String input = "(case :a ((:a) 'banana))";
-
-        assertSExpressionsMatch(parseString("banana"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithOneClause_NoMatch() {
-        String input = "(case :a ((:b) 'banana))";
-
-        assertSExpressionsMatch(parseString("nil"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithSeveralClauses_Match() {
-        String input = "(case :a ((:b) 'orange) ((:a) 'banana))";
-
-        assertSExpressionsMatch(parseString("banana"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithSeveralClauses_NoMatch() {
-        String input = "(case :a ((:b) 'orange) ((:c) 'banana))";
-
-        assertSExpressionsMatch(parseString("nil"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithSeveralItemsInKeyList_Match() {
-        String input = "(case :a ((:b :a) 'orange) ((:c :d) 'banana))";
-
-        assertSExpressionsMatch(parseString("orange"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithSeveralItemsInKeyList_NoMatch() {
-        String input = "(case :a ((:b :f) 'orange) ((:c :d) 'banana))";
-
-        assertSExpressionsMatch(parseString("nil"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithSymbolicKeyList_Match() {
-        String input = "(case :a (:a 'orange))";
-
-        assertSExpressionsMatch(parseString("orange"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithSymbolicKeyList_NoMatch() {
-        String input = "(case :a (:b 'orange))";
-
-        assertSExpressionsMatch(parseString("nil"), evaluateString(input));
-    }
-
-    @Test
-    public void caseDoesNotEvaluateKeyList() {
-        String input = "(case 'x ((x) t))";
-
-        assertSExpressionsMatch(parseString("t"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithEmptyKeyList() {
-        String input = "(case nil (() 'orange))";
-
-        assertSExpressionsMatch(parseString("nil"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithNil() {
-        String input = "(case nil ((nil) 'orange))";
-
-        assertSExpressionsMatch(parseString("orange"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithEmptyList() {
-        String input = "(case () ((()) 'orange))";
-
-        assertSExpressionsMatch(parseString("orange"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithList() {
-        String input = "(case '(5 4 3) (((1 2) (5 4 3)) 'orange))";
-
-        assertSExpressionsMatch(parseString("orange"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithDefaultClause() {
-        String input = "(case nil (() 'banana) (t 'orange))";
-
-        assertSExpressionsMatch(parseString("orange"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithOutOfOrderDefaultClause() {
-        String input = "(case :a (t 'orange) (:a 'banana))";
-
-        assertSExpressionsMatch(parseString("orange"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithKeyListContainingT() {
-        String input = "(case t ((t) 'banana))";
-
-        assertSExpressionsMatch(parseString("banana"), evaluateString(input));
-    }
-
-    @Test
-    public void caseWithMultipleMatches_ReturnsFirst() {
-        String input = "(case 2 ((0) 'banana) ((1) 'apple) ((2) 'avocado) ((2) 'greenbean))";
-
-        assertSExpressionsMatch(parseString("avocado"), evaluateString(input));
-    }
-
-    @Test
-    public void caseEvaluatesMultipleConsequents() {
-        String input = "(case 2 (1 1) (2 (setq x 'x) (setq y 'y)) (3 3)))";
-
-        evaluateString(input);
-
-        assertSExpressionsMatch(parseString("x"), evaluateString("x"));
-        assertSExpressionsMatch(parseString("y"), evaluateString("y"));
-    }
-
-    @Test
-    public void caseReturnsValueOfLastConsequent() {
-        String input = "(case 2 (1 1) (2 3 4 5) (3 3))";
-
-        assertSExpressionsMatch(parseString("5"), evaluateString(input));
-    }
-
-    @Test
-    public void caseOnlyEvaluatesConsequentInFirstMatchingClause() {
-        String input = "(case 2 ((0) (setq zero 0)) ((1) (setq one 1)) ((2) (setq two '2)) ((2) (setq two 'two)))";
-
-        evaluateString("(setq zero nil)");
-        evaluateString("(setq one nil)");
-        evaluateString(input);
-
-        assertSExpressionsMatch(parseString("nil"), evaluateString("zero"));
-        assertSExpressionsMatch(parseString("nil"), evaluateString("one"));
-        assertSExpressionsMatch(parseString("2"), evaluateString("two"));
-    }
-
-    @Test(expected = TooFewArgumentsException.class)
-    public void caseWithTooFewArguments() {
-        evaluateString("(case)");
-    }
-
-    @Test(expected = BadArgumentTypeException.class)
-    public void caseWithNonListClause() {
-        evaluateString("(case :a t)");
-    }
-
-    @Test(expected = BadArgumentTypeException.class)
-    public void caseWithEmptyClause() {
-        evaluateString("(case :a ())");
-    }
-
-    @Test(expected = BadArgumentTypeException.class)
-    public void caseWithNilClause() {
-        evaluateString("(case :a nil)");
-    }
-}
diff --git a/src/test/kotlin/function/builtin/special/CaseTest.kt b/src/test/kotlin/function/builtin/special/CaseTest.kt
new file mode 100644
index 0000000..df7da51
--- /dev/null
+++ b/src/test/kotlin/function/builtin/special/CaseTest.kt
@@ -0,0 +1,206 @@
+package function.builtin.special
+
+import function.ArgumentValidator.BadArgumentTypeException
+import function.ArgumentValidator.TooFewArgumentsException
+import org.junit.jupiter.api.Assertions.assertThrows
+import org.junit.jupiter.api.Test
+import testutil.LispTestInstance
+import testutil.SymbolAndFunctionCleaner
+import testutil.TestUtilities.assertSExpressionsMatch
+import testutil.TestUtilities.evaluateString
+import testutil.TestUtilities.parseString
+
+@LispTestInstance
+class CaseTest : SymbolAndFunctionCleaner() {
+
+    @Test
+    fun caseWithKeyOnly() {
+        val input = "(case t)"
+
+        assertSExpressionsMatch(parseString("nil"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithEmptyConsequent() {
+        val input = "(case :a ((:a)))"
+
+        assertSExpressionsMatch(parseString("nil"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithOneClause_Match() {
+        val input = "(case :a ((:a) 'banana))"
+
+        assertSExpressionsMatch(parseString("banana"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithOneClause_NoMatch() {
+        val input = "(case :a ((:b) 'banana))"
+
+        assertSExpressionsMatch(parseString("nil"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithSeveralClauses_Match() {
+        val input = "(case :a ((:b) 'orange) ((:a) 'banana))"
+
+        assertSExpressionsMatch(parseString("banana"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithSeveralClauses_NoMatch() {
+        val input = "(case :a ((:b) 'orange) ((:c) 'banana))"
+
+        assertSExpressionsMatch(parseString("nil"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithSeveralItemsInKeyList_Match() {
+        val input = "(case :a ((:b :a) 'orange) ((:c :d) 'banana))"
+
+        assertSExpressionsMatch(parseString("orange"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithSeveralItemsInKeyList_NoMatch() {
+        val input = "(case :a ((:b :f) 'orange) ((:c :d) 'banana))"
+
+        assertSExpressionsMatch(parseString("nil"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithSymbolicKeyList_Match() {
+        val input = "(case :a (:a 'orange))"
+
+        assertSExpressionsMatch(parseString("orange"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithSymbolicKeyList_NoMatch() {
+        val input = "(case :a (:b 'orange))"
+
+        assertSExpressionsMatch(parseString("nil"), evaluateString(input))
+    }
+
+    @Test
+    fun caseDoesNotEvaluateKeyList() {
+        val input = "(case 'x ((x) t))"
+
+        assertSExpressionsMatch(parseString("t"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithEmptyKeyList() {
+        val input = "(case nil (() 'orange))"
+
+        assertSExpressionsMatch(parseString("nil"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithNil() {
+        val input = "(case nil ((nil) 'orange))"
+
+        assertSExpressionsMatch(parseString("orange"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithEmptyList() {
+        val input = "(case () ((()) 'orange))"
+
+        assertSExpressionsMatch(parseString("orange"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithList() {
+        val input = "(case '(5 4 3) (((1 2) (5 4 3)) 'orange))"
+
+        assertSExpressionsMatch(parseString("orange"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithDefaultClause() {
+        val input = "(case nil (() 'banana) (t 'orange))"
+
+        assertSExpressionsMatch(parseString("orange"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithOutOfOrderDefaultClause() {
+        val input = "(case :a (t 'orange) (:a 'banana))"
+
+        assertSExpressionsMatch(parseString("orange"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithKeyListContainingT() {
+        val input = "(case t ((t) 'banana))"
+
+        assertSExpressionsMatch(parseString("banana"), evaluateString(input))
+    }
+
+    @Test
+    fun caseWithMultipleMatches_ReturnsFirst() {
+        val input = "(case 2 ((0) 'banana) ((1) 'apple) ((2) 'avocado) ((2) 'greenbean))"
+
+        assertSExpressionsMatch(parseString("avocado"), evaluateString(input))
+    }
+
+    @Test
+    fun caseEvaluatesMultipleConsequents() {
+        val input = "(case 2 (1 1) (2 (setq x 'x) (setq y 'y)) (3 3)))"
+
+        evaluateString(input)
+
+        assertSExpressionsMatch(parseString("x"), evaluateString("x"))
+        assertSExpressionsMatch(parseString("y"), evaluateString("y"))
+    }
+
+    @Test
+    fun caseReturnsValueOfLastConsequent() {
+        val input = "(case 2 (1 1) (2 3 4 5) (3 3))"
+
+        assertSExpressionsMatch(parseString("5"), evaluateString(input))
+    }
+
+    @Test
+    fun caseOnlyEvaluatesConsequentInFirstMatchingClause() {
+        val input = "(case 2 ((0) (setq zero 0)) ((1) (setq one 1)) ((2) (setq two '2)) ((2) (setq two 'two)))"
+
+        evaluateString("(setq zero nil)")
+        evaluateString("(setq one nil)")
+        evaluateString(input)
+
+        assertSExpressionsMatch(parseString("nil"), evaluateString("zero"))
+        assertSExpressionsMatch(parseString("nil"), evaluateString("one"))
+        assertSExpressionsMatch(parseString("2"), evaluateString("two"))
+    }
+
+    @Test
+    fun caseWithTooFewArguments() {
+        assertThrows(TooFewArgumentsException::class.java) {
+            evaluateString("(case)")
+        }
+    }
+
+    @Test
+    fun caseWithNonListClause() {
+        assertThrows(BadArgumentTypeException::class.java) {
+            evaluateString("(case :a t)")
+        }
+    }
+
+    @Test
+    fun caseWithEmptyClause() {
+        assertThrows(BadArgumentTypeException::class.java) {
+            evaluateString("(case :a ())")
+        }
+    }
+
+    @Test
+    fun caseWithNilClause() {
+        assertThrows(BadArgumentTypeException::class.java) {
+            evaluateString("(case :a nil)")
+        }
+    }
+}