Convert Eval to kotlin

pom.xml

@@ -10,7 +10,7 @@
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <kotlin.version>1.2.70</kotlin.version>
+    <kotlin.version>1.2.71</kotlin.version>
     <junit5.version>5.2.0</junit5.version>
     <skipTests>false</skipTests>
   </properties>

src/main/kotlin/function/UserDefinedFunction.kt

@@ -1,7 +1,7 @@
 package function
 
 import error.LispException
-import function.builtin.EVAL.eval
+import function.builtin.Eval.Companion.eval
 import sexpression.Cons
 import sexpression.Nil
 import sexpression.SExpression

src/main/kotlin/function/builtin/APPLY.java

@@ -7,8 +7,8 @@ import sexpression.Cons;
 import sexpression.SExpression;
 import table.FunctionTable;
 
-import static function.builtin.EVAL.applyFunction;
-import static function.builtin.EVAL.lookupFunctionOrLambda;
+import static function.builtin.Eval.applyFunction;
+import static function.builtin.Eval.lookupFunctionOrLambda;
 
 @FunctionNames({ "APPLY" })
 public class APPLY extends LispFunction {

src/main/kotlin/function/builtin/BackquoteEvaluator.java

@@ -9,7 +9,7 @@ import sexpression.Cons;
 import sexpression.Nil;
 import sexpression.SExpression;
 
-import static function.builtin.EVAL.eval;
+import static function.builtin.Eval.eval;
 
 class BackquoteEvaluator {
 

src/main/kotlin/function/builtin/EVAL.java

@@ -1,229 +0,0 @@
-package function.builtin;
-
-import error.LispException;
-import function.ArgumentValidator;
-import function.FunctionNames;
-import function.LispFunction;
-import function.builtin.special.RECUR.RecurNotInTailPositionException;
-import sexpression.BackquoteExpression;
-import sexpression.Cons;
-import sexpression.LambdaExpression;
-import sexpression.Nil;
-import sexpression.SExpression;
-import sexpression.Symbol;
-import table.ExecutionContext;
-import table.FunctionTable;
-
-import static function.builtin.cons.LIST.makeList;
-import static function.builtin.special.Lambda.Lambda;
-import static java.text.MessageFormat.format;
-
-@FunctionNames({ "EVAL" })
-public class EVAL extends LispFunction {
-
-    private static ExecutionContext executionContext = ExecutionContext.INSTANCE;
-
-    public static SExpression eval(SExpression sExpression) {
-        Cons argumentList = makeList(sExpression);
-
-        try {
-            return lookupEval().call(argumentList);
-        } catch (LispException e) {
-            executionContext.restoreGlobalScope();
-            throw e;
-        }
-    }
-
-    public static SExpression applyFunction(LispFunction function, Cons argumentList) {
-        return lookupEval().applyFunctionWithoutEvaluatingArguments(function, argumentList);
-    }
-
-    public static Cons evaluateFunctionArgumentList(Cons argumentList) {
-        return lookupEval().evaluateArgumentList(argumentList);
-    }
-
-    private static EVAL lookupEval() {
-        return (EVAL) FunctionTable.INSTANCE.lookupFunction("EVAL");
-    }
-
-    public static LispFunction lookupFunctionOrLambda(SExpression functionExpression) {
-        LispFunction function = FunctionTable.INSTANCE.lookupFunction(functionExpression.toString());
-
-        if (function == null)
-            function = createLambdaFunction(functionExpression);
-
-        return function;
-    }
-
-    private static LispFunction createLambdaFunction(SExpression lambdaExpression) {
-        if (lambdaExpression.isFunction())
-            return ((LambdaExpression) lambdaExpression).getFunction();
-        else if (Lambda.isLambdaExpression(lambdaExpression))
-            return Lambda.createFunction((Cons) lambdaExpression);
-        else
-            throw new UndefinedFunctionException(lambdaExpression);
-    }
-
-    public static SExpression lookupSymbol(String symbolName) {
-        if (symbolName.equals("NIL"))
-            return Nil.INSTANCE;
-        else if (symbolName.equals("T"))
-            return Symbol.Companion.getT();
-        else if (symbolName.startsWith(":"))
-            return new Symbol(symbolName);
-
-        return ExecutionContext.INSTANCE.lookupSymbolValue(symbolName);
-    }
-
-    private ArgumentValidator argumentValidator;
-
-    public EVAL(String name) {
-        this.argumentValidator = new ArgumentValidator(name);
-        this.argumentValidator.setExactNumberOfArguments(1);
-    }
-
-    @Override
-    public SExpression call(Cons argumentList) {
-        verifyNotRecurring();
-        argumentValidator.validate(argumentList);
-        SExpression argument = argumentList.getFirst();
-
-        return evaluateExpression(argument);
-    }
-
-    private void verifyNotRecurring() {
-        if (executionContext.isRecur()) {
-            executionContext.clearRecur();
-            throw new RecurNotInTailPositionException();
-        }
-    }
-
-    private SExpression evaluateExpression(SExpression argument) {
-        if (argument.isList())
-            return evaluateList(argument);
-        else if (argument.isSymbol())
-            return evaluateSymbol(argument);
-        else if (argument.isBackquote())
-            return evaluateBackTick(argument);
-        else if (argument.isComma())
-            throw new UnmatchedCommaException();
-        else if (argument.isAtSign())
-            throw new UnmatchedAtSignException();
-
-        return argument; // NUMBER or STRING
-    }
-
-    private SExpression evaluateList(SExpression argument) {
-        if (argument.isCons())
-            return evaluateFunction((Cons) argument);
-
-        return argument; // NIL
-    }
-
-    private SExpression evaluateFunction(Cons list) {
-        SExpression functionName = list.getFirst();
-        SExpression arguments = list.getRest();
-        LispFunction function = lookupFunctionOrLambda(functionName);
-        validateFunctionList(list, functionName);
-
-        return callFunction(function, (Cons) arguments);
-    }
-
-    private void validateFunctionList(Cons list, SExpression functionName) {
-        ArgumentValidator functionListValidator = new ArgumentValidator(functionName.toString());
-        functionListValidator.validate(list);
-    }
-
-    private SExpression callFunction(LispFunction function, Cons argumentList) {
-        if (function.isArgumentListEvaluated())
-            argumentList = evaluateArgumentList(argumentList);
-
-        return applyFunctionWithoutEvaluatingArguments(function, argumentList);
-    }
-
-    private SExpression applyFunctionWithoutEvaluatingArguments(LispFunction function, Cons argumentList) {
-        verifyNotRecurring();
-
-        SExpression result = function.call(argumentList);
-
-        if (function.isMacro())
-            result = eval(result);
-
-        return result;
-    }
-
-    private Cons evaluateArgumentList(Cons arguments) {
-        if (arguments.isNull())
-            return Nil.INSTANCE;
-
-        SExpression first = eval(arguments.getFirst());
-        SExpression rest = arguments.getRest();
-
-        return new Cons(first, evaluateArgumentList((Cons) rest));
-    }
-
-    private SExpression evaluateSymbol(SExpression argument) {
-        SExpression symbolValue = lookupSymbol(argument.toString());
-
-        if (symbolValue != null)
-            return symbolValue;
-
-        throw new UndefinedSymbolException(argument);
-    }
-
-    private SExpression evaluateBackTick(SExpression argument) {
-        BackquoteEvaluator evaluator = new BackquoteEvaluator((BackquoteExpression) argument);
-
-        return evaluator.evaluate();
-    }
-
-    public static class UndefinedFunctionException extends LispException {
-
-        private static final long serialVersionUID = 1L;
-        private SExpression function;
-
-        public UndefinedFunctionException(SExpression function) {
-            this.function = function;
-        }
-
-        @Override
-        public String getMessage() {
-            return format("undefined function: {0}", function);
-        }
-    }
-
-    public static class UndefinedSymbolException extends LispException {
-
-        private static final long serialVersionUID = 1L;
-        private SExpression symbol;
-
-        public UndefinedSymbolException(SExpression symbol) {
-            this.symbol = symbol;
-        }
-
-        @Override
-        public String getMessage() {
-            return format("symbol {0} has no value", symbol);
-        }
-    }
-
-    public static class UnmatchedCommaException extends LispException {
-
-        private static final long serialVersionUID = 1L;
-
-        @Override
-        public String getMessage() {
-            return "unmatched comma";
-        }
-    }
-
-    public static class UnmatchedAtSignException extends LispException {
-
-        private static final long serialVersionUID = 1L;
-
-        @Override
-        public String getMessage() {
-            return "unmatched at sign";
-        }
-    }
-}

src/main/kotlin/function/builtin/Eval.kt

@@ -0,0 +1,161 @@
+package function.builtin
+
+import error.LispException
+import function.ArgumentValidator
+import function.FunctionNames
+import function.LispFunction
+import function.builtin.cons.LIST.makeList
+import function.builtin.special.Lambda.Lambda.createFunction
+import function.builtin.special.Lambda.Lambda.isLambdaExpression
+import function.builtin.special.RECUR.RecurNotInTailPositionException
+import sexpression.BackquoteExpression
+import sexpression.Cons
+import sexpression.LambdaExpression
+import sexpression.Nil
+import sexpression.SExpression
+import sexpression.Symbol
+import table.ExecutionContext
+import table.FunctionTable
+
+@FunctionNames("EVAL")
+class Eval(name: String) : LispFunction() {
+
+    private val argumentValidator: ArgumentValidator = ArgumentValidator(name).apply {
+        setExactNumberOfArguments(1)
+    }
+
+    override fun call(argumentList: Cons): SExpression {
+        verifyNotRecurring()
+        argumentValidator.validate(argumentList)
+
+        return evaluateExpression(argumentList.first)
+    }
+
+    private fun verifyNotRecurring() {
+        if (ExecutionContext.isRecur) {
+            ExecutionContext.clearRecur()
+            throw RecurNotInTailPositionException()
+        }
+    }
+
+    private fun evaluateExpression(argument: SExpression) = when {
+        argument.isList      -> evaluateList(argument)
+        argument.isSymbol    -> evaluateSymbol(argument)
+        argument.isBackquote -> evaluateBackTick(argument)
+        argument.isComma     -> throw UnmatchedCommaException()
+        argument.isAtSign    -> throw UnmatchedAtSignException()
+        else                 -> argument // NUMBER or STRING
+    }
+
+    private fun evaluateList(argument: SExpression) =
+        if (argument.isCons)
+            evaluateFunction(argument as Cons)
+        else
+            argument // NIL
+
+    private fun evaluateFunction(list: Cons): SExpression {
+        val functionName = list.first
+        val arguments = list.rest
+        val function = lookupFunctionOrLambda(functionName)
+        validateFunctionList(list, functionName)
+
+        return callFunction(function, arguments as Cons)
+    }
+
+    private fun validateFunctionList(list: Cons, functionName: SExpression) {
+        ArgumentValidator(functionName.toString()).validate(list)
+    }
+
+    private fun callFunction(function: LispFunction, argumentList: Cons) =
+        if (function.isArgumentListEvaluated)
+            applyFunctionWithoutEvaluatingArguments(function, evaluateArgumentList(argumentList))
+        else
+            applyFunctionWithoutEvaluatingArguments(function, argumentList)
+
+    private fun applyFunctionWithoutEvaluatingArguments(function: LispFunction, argumentList: Cons): SExpression {
+        verifyNotRecurring()
+
+        return function.call(argumentList).let {
+            if (function.isMacro) eval(it) else it
+        }
+    }
+
+    private fun evaluateArgumentList(arguments: Cons): Cons {
+        if (arguments.isNull)
+            return Nil
+
+        val first = eval(arguments.first)
+        val rest = arguments.rest as Cons
+
+        return Cons(first, evaluateArgumentList(rest))
+    }
+
+    private fun evaluateSymbol(argument: SExpression) =
+        lookupSymbol(argument.toString()) ?: throw UndefinedSymbolException(argument)
+
+    private fun evaluateBackTick(argument: SExpression) =
+        BackquoteEvaluator(argument as BackquoteExpression).evaluate()
+
+    companion object {
+
+        private fun lookupEval() = FunctionTable.lookupFunction("EVAL") as Eval
+
+        @JvmStatic
+        fun eval(sExpression: SExpression): SExpression {
+            try {
+                return lookupEval().call(makeList(sExpression))
+            } catch (e: LispException) {
+                ExecutionContext.restoreGlobalScope()
+                throw e
+            }
+        }
+
+        @JvmStatic
+        fun applyFunction(function: LispFunction, argumentList: Cons) =
+            lookupEval().applyFunctionWithoutEvaluatingArguments(function, argumentList)
+
+        @JvmStatic
+        fun evaluateFunctionArgumentList(argumentList: Cons) = lookupEval().evaluateArgumentList(argumentList)
+
+        @JvmStatic
+        fun lookupSymbol(symbolName: String) = when {
+            symbolName == "NIL"        -> Nil
+            symbolName == "T"          -> Symbol.T
+            symbolName.startsWith(":") -> Symbol(symbolName)
+            else                       -> ExecutionContext.lookupSymbolValue(symbolName)
+        }
+
+        @JvmStatic
+        fun lookupFunctionOrLambda(functionExpression: SExpression): LispFunction {
+            val function = FunctionTable.lookupFunction(functionExpression.toString())
+
+            return function ?: createLambdaFunction(functionExpression)
+        }
+
+        private fun createLambdaFunction(lambdaExpression: SExpression) = when {
+            lambdaExpression.isFunction          -> (lambdaExpression as LambdaExpression).function
+            isLambdaExpression(lambdaExpression) -> createFunction(lambdaExpression as Cons)
+            else                                 -> throw UndefinedFunctionException(lambdaExpression)
+        }
+    }
+
+    class UndefinedFunctionException(function: SExpression) : LispException() {
+
+        override val message = "undefined function: $function"
+    }
+
+    class UndefinedSymbolException(symbol: SExpression) : LispException() {
+
+        override val message = "symbol $symbol has no value"
+    }
+
+    class UnmatchedCommaException : LispException() {
+
+        override val message = "unmatched comma"
+    }
+
+    class UnmatchedAtSignException : LispException() {
+
+        override val message = "unmatched at sign"
+    }
+}

src/main/kotlin/function/builtin/LOAD.java

@@ -18,7 +18,7 @@ import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.util.Stack;
 
-import static function.builtin.EVAL.eval;
+import static function.builtin.Eval.eval;
 import static java.text.MessageFormat.format;
 
 @FunctionNames({ "LOAD" })

src/main/kotlin/function/builtin/special/AND.java

@@ -8,7 +8,7 @@ import sexpression.Cons;
 import sexpression.SExpression;
 import sexpression.Symbol;
 
-import static function.builtin.EVAL.eval;
+import static function.builtin.Eval.eval;
 import static recursion.TailCalls.done;
 import static recursion.TailCalls.tailCall;
 

src/main/kotlin/function/builtin/special/CASE.java

@@ -9,7 +9,7 @@ import sexpression.Nil;
 import sexpression.SExpression;
 import sexpression.Symbol;
 
-import static function.builtin.EVAL.eval;
+import static function.builtin.Eval.eval;
 import static function.builtin.predicate.EQUAL.isEqual;
 import static recursion.TailCalls.done;
 import static recursion.TailCalls.tailCall;

src/main/kotlin/function/builtin/special/COND.java

@@ -8,7 +8,7 @@ import sexpression.Cons;
 import sexpression.Nil;
 import sexpression.SExpression;
 
-import static function.builtin.EVAL.eval;
+import static function.builtin.Eval.eval;
 import static recursion.TailCalls.done;
 import static recursion.TailCalls.tailCall;
 

src/main/kotlin/function/builtin/special/IF.java

@@ -6,7 +6,7 @@ import function.LispSpecialFunction;
 import sexpression.Cons;
 import sexpression.SExpression;
 
-import static function.builtin.EVAL.eval;
+import static function.builtin.Eval.eval;
 
 @FunctionNames({ "IF" })
 public class IF extends LispSpecialFunction {

src/main/kotlin/function/builtin/special/LET.java

@@ -10,7 +10,7 @@ import sexpression.Symbol;
 import table.ExecutionContext;
 import table.SymbolTable;
 
-import static function.builtin.EVAL.eval;
+import static function.builtin.Eval.eval;
 
 @FunctionNames({ "LET" })
 public class LET extends LispSpecialFunction {

src/main/kotlin/function/builtin/special/OR.java

@@ -7,7 +7,7 @@ import recursion.TailCall;
 import sexpression.Cons;
 import sexpression.SExpression;
 
-import static function.builtin.EVAL.eval;
+import static function.builtin.Eval.eval;
 import static recursion.TailCalls.done;
 import static recursion.TailCalls.tailCall;
 

src/main/kotlin/function/builtin/special/PROGN.java

@@ -8,7 +8,7 @@ import sexpression.Cons;
 import sexpression.Nil;
 import sexpression.SExpression;
 
-import static function.builtin.EVAL.eval;
+import static function.builtin.Eval.eval;
 import static recursion.TailCalls.done;
 import static recursion.TailCalls.tailCall;
 

src/main/kotlin/function/builtin/special/RECUR.java

@@ -8,7 +8,7 @@ import sexpression.Cons;
 import sexpression.SExpression;
 import table.ExecutionContext;
 
-import static function.builtin.EVAL.evaluateFunctionArgumentList;
+import static function.builtin.Eval.evaluateFunctionArgumentList;
 
 @FunctionNames({ "RECUR" })
 public class RECUR extends LispSpecialFunction {

src/main/kotlin/function/builtin/special/SETQ.java

@@ -7,7 +7,7 @@ import sexpression.Cons;
 import sexpression.SExpression;
 import sexpression.Symbol;
 
-import static function.builtin.EVAL.eval;
+import static function.builtin.Eval.eval;
 import static function.builtin.SET.set;
 import static function.builtin.cons.LIST.makeList;
 

src/main/kotlin/interpreter/LispInterpreter.kt

@@ -6,7 +6,7 @@ import environment.RuntimeEnvironment.input
 import environment.RuntimeEnvironment.inputName
 import environment.RuntimeEnvironment.output
 import error.LispException
-import function.builtin.EVAL.eval
+import function.builtin.Eval.Companion.eval
 import parser.LispParser
 import sexpression.SExpression
 import java.io.InputStream

src/main/kotlin/table/FunctionTable.kt

@@ -4,7 +4,7 @@ import error.CriticalLispException
 import function.FunctionNames
 import function.LispFunction
 import function.builtin.APPLY
-import function.builtin.EVAL
+import function.builtin.Eval
 import function.builtin.Exit
 import function.builtin.FUNCALL
 import function.builtin.FUSE
@@ -68,7 +68,7 @@ object FunctionTable {
             EQ::class.java,
             EQUAL::class.java,
             NumericEqual::class.java,
-            EVAL::class.java,
+            Eval::class.java,
             Exit::class.java,
             FIRST::class.java,
             FUNCALL::class.java,

src/test/kotlin/function/builtin/APPLYTest.java

@@ -4,7 +4,7 @@ import function.ArgumentValidator.BadArgumentTypeException;
 import function.ArgumentValidator.DottedArgumentListException;
 import function.ArgumentValidator.TooFewArgumentsException;
 import function.ArgumentValidator.TooManyArgumentsException;
-import function.builtin.EVAL.UndefinedFunctionException;
+import function.builtin.Eval.UndefinedFunctionException;
 import org.junit.Test;
 import sexpression.Cons;
 import testutil.SymbolAndFunctionCleaner;

src/test/kotlin/function/builtin/EVALTest.java

@@ -1,256 +0,0 @@
-package function.builtin;
-
-import function.ArgumentValidator.DottedArgumentListException;
-import function.ArgumentValidator.TooFewArgumentsException;
-import function.ArgumentValidator.TooManyArgumentsException;
-import function.builtin.BackquoteEvaluator.AtSignNotInCommaException;
-import function.builtin.EVAL.UndefinedFunctionException;
-import function.builtin.EVAL.UndefinedSymbolException;
-import function.builtin.EVAL.UnmatchedAtSignException;
-import function.builtin.EVAL.UnmatchedCommaException;
-import function.builtin.special.RECUR.RecurNotInTailPositionException;
-import org.junit.Test;
-import sexpression.Nil;
-import testutil.SymbolAndFunctionCleaner;
-
-import static function.builtin.EVAL.lookupSymbol;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.fail;
-import static testutil.TestUtilities.assertIsErrorWithMessage;
-import static testutil.TestUtilities.assertSExpressionsMatch;
-import static testutil.TestUtilities.evaluateString;
-import static testutil.TestUtilities.parseString;
-
-public class EVALTest extends SymbolAndFunctionCleaner {
-
-    @Test
-    public void evalNumber() {
-        String input = "(eval 9)";
-
-        assertSExpressionsMatch(parseString("9"), evaluateString(input));
-    }
-
-    @Test
-    public void evalNil() {
-        String input = "(eval ())";
-
-        assertSExpressionsMatch(parseString("()"), evaluateString(input));
-    }
-
-    @Test
-    public void evalUsesCurrentLexicalEnvironment() {
-        String input = "(let ((x 1)) (eval '(+ x 1)))";
-
-        assertSExpressionsMatch(parseString("2"), evaluateString(input));
-    }
-
-    @Test
-    public void lookupKeywordSymbol() {
-        String symbol = ":symbol";
-        assertSExpressionsMatch(parseString(symbol), lookupSymbol(symbol));
-    }
-
-    @Test
-    public void lookupT() {
-        String symbol = "T";
-        assertSExpressionsMatch(parseString(symbol), lookupSymbol(symbol));
-    }
-
-    @Test
-    public void lookupNil() {
-        String symbol = "NIL";
-        assertSExpressionsMatch(parseString(symbol), lookupSymbol(symbol));
-    }
-
-    @Test
-    public void lookupUndefinedSymbol() {
-        assertNull(EVAL.lookupSymbol("undefined"));
-    }
-
-    @Test(expected = UndefinedFunctionException.class)
-    public void evalUndefinedFunction() {
-        String input = "(funcall 'eval '(undefined))";
-
-        evaluateString(input);
-    }
-
-    @Test(expected = UndefinedSymbolException.class)
-    public void evalUndefinedSymbol() {
-        String input = "(eval undefined)";
-
-        evaluateString(input);
-    }
-
-    @Test(expected = DottedArgumentListException.class)
-    public void evalWithDottedLambdaList() {
-        String input = "(funcall 'eval (cons '+ 1))";
-
-        evaluateString(input);
-    }
-
-    @Test(expected = TooManyArgumentsException.class)
-    public void evalWithTooManyArguments() {
-        evaluateString("(eval '1 '2 '3)");
-    }
-
-    @Test(expected = TooFewArgumentsException.class)
-    public void evalWithTooFewArguments() {
-        evaluateString("(eval)");
-    }
-
-    @Test
-    public void undefinedFunctionException_HasCorrectAttributes() {
-        assertIsErrorWithMessage(new UndefinedFunctionException(Nil.INSTANCE));
-    }
-
-    @Test
-    public void undefinedSymbolException_HasCorrectAttributes() {
-        assertIsErrorWithMessage(new UndefinedSymbolException(Nil.INSTANCE));
-    }
-
-    @Test(expected = UnmatchedCommaException.class)
-    public void evalComma() {
-        String input = ",a";
-
-        evaluateString(input);
-    }
-
-    @Test(expected = UnmatchedAtSignException.class)
-    public void evalAtSign() {
-        String input = "@a";
-
-        evaluateString(input);
-    }
-
-    @Test
-    public void evalBackTick() {
-        String input = "`(a b c)";
-
-        assertSExpressionsMatch(parseString("(a b c)"), evaluateString(input));
-    }
-
-    @Test
-    public void evalBackTickWithCommasAndAtSigns() {
-        String input = "(let ((x '(1 2 3)) (y '(4 5 6)) (z 'apple)) `(start ,x ,@y ,z end))";
-
-        assertSExpressionsMatch(parseString("(start (1 2 3) 4 5 6 apple end)"), evaluateString(input));
-    }
-
-    @Test
-    public void evalBackTickOnComma() {
-        String input = "`,9";
-
-        assertSExpressionsMatch(parseString("9"), evaluateString(input));
-    }
-
-    @Test(expected = AtSignNotInCommaException.class)
-    public void evalBackTickOnAtSign() {
-        evaluateString("`@9");
-    }
-
-    @Test
-    public void evalNestedBackquotes() {
-        String input = "`,`,`,`,9";
-
-        assertSExpressionsMatch(parseString("9"), evaluateString(input));
-    }
-
-    @Test
-    public void unmatchedCommaException_HasCorrectAttributes() {
-        assertIsErrorWithMessage(new UnmatchedCommaException());
-    }
-
-    @Test
-    public void unmatchedAtSignException_HasCorrectAttributes() {
-        assertIsErrorWithMessage(new UnmatchedAtSignException());
-    }
-
-    @Test
-    public void evalQuoteInNestedList() {
-        String input = "(let ((g 27)) `((,g)))";
-
-        assertSExpressionsMatch(parseString("((27))"), evaluateString(input));
-    }
-
-    @Test
-    public void evalAtSignInNestedList() {
-        String input = "(let ((g '(1 2 3))) `((,@g)))";
-
-        assertSExpressionsMatch(parseString("((1 2 3))"), evaluateString(input));
-    }
-
-    @Test
-    public void evalNestedBackquotesInList() {
-        String input = "`(,`(1 ,`2 ,@`(3)))";
-
-        assertSExpressionsMatch(parseString("((1 2 3))"), evaluateString(input));
-    }
-
-    @Test
-    public void scopeRestoredAfterFailure_Let() {
-        evaluateString("(setq n 100)");
-
-        try {
-            evaluateString("(let ((n 200)) (begin 1 2 3 y))");
-            fail("expected exception");
-        } catch (UndefinedSymbolException e) {
-        }
-
-        assertSExpressionsMatch(parseString("100"), evaluateString("n"));
-    }
-
-    @Test
-    public void scopeRestoredAfterFailure_Defun() {
-        evaluateString("(setq n 100)");
-
-        try {
-            evaluateString("(defun test (n) (begin 1 2 3 y))");
-            evaluateString("(test 200)");
-            fail("expected exception");
-        } catch (UndefinedSymbolException e) {
-        }
-
-        assertSExpressionsMatch(parseString("100"), evaluateString("n"));
-    }
-
-    @Test
-    public void scopeRestoredAfterFailure_Lambda() {
-        evaluateString("(setq n 100)");
-
-        try {
-            evaluateString("((lambda (n) (begin 1 2 3 y)) 200)");
-            fail("expected exception");
-        } catch (UndefinedSymbolException e) {
-        }
-
-        assertSExpressionsMatch(parseString("100"), evaluateString("n"));
-    }
-
-    @Test
-    public void scopeRestoredAfterFailure_Recur() {
-        evaluateString("(setq n 100)");
-
-        try {
-            evaluateString("(defun tail-recursive (n) (begin (recur) 2))");
-            evaluateString("(tail-recursive 200)");
-            fail("expected exception");
-        } catch (RecurNotInTailPositionException e) {
-        }
-
-        assertSExpressionsMatch(parseString("100"), evaluateString("n"));
-    }
-
-    @Test
-    public void scopeRestoredAfterFailure_Apply() {
-        evaluateString("(setq n 100)");
-
-        try {
-            evaluateString("(defun tail-recursive (n) (begin (recur) 2))");
-            evaluateString("(apply 'tail-recursive '(200))");
-            fail("expected exception");
-        } catch (RecurNotInTailPositionException e) {
-        }
-
-        assertSExpressionsMatch(parseString("100"), evaluateString("n"));
-    }
-}

src/test/kotlin/function/builtin/EvalTest.kt

@@ -0,0 +1,278 @@
+package function.builtin
+
+import function.ArgumentValidator.DottedArgumentListException
+import function.ArgumentValidator.TooFewArgumentsException
+import function.ArgumentValidator.TooManyArgumentsException
+import function.builtin.BackquoteEvaluator.AtSignNotInCommaException
+import function.builtin.Eval.Companion.lookupSymbol
+import function.builtin.Eval.UndefinedFunctionException
+import function.builtin.Eval.UndefinedSymbolException
+import function.builtin.Eval.UnmatchedAtSignException
+import function.builtin.Eval.UnmatchedCommaException
+import function.builtin.special.RECUR.RecurNotInTailPositionException
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Assertions.assertThrows
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.TestInstance
+import org.junit.jupiter.api.TestInstance.Lifecycle.PER_CLASS
+import org.junit.jupiter.api.fail
+import sexpression.Nil
+import testutil.SymbolAndFunctionCleaner
+import testutil.TestUtilities.assertIsErrorWithMessage
+import testutil.TestUtilities.assertSExpressionsMatch
+import testutil.TestUtilities.evaluateString
+import testutil.TestUtilities.parseString
+
+@TestInstance(PER_CLASS)
+class EvalTest : SymbolAndFunctionCleaner() {
+
+    @Test
+    fun evalNumber() {
+        val input = "(eval 9)"
+
+        assertSExpressionsMatch(parseString("9"), evaluateString(input))
+    }
+
+    @Test
+    fun evalNil() {
+        val input = "(eval ())"
+
+        assertSExpressionsMatch(parseString("()"), evaluateString(input))
+    }
+
+    @Test
+    fun evalUsesCurrentLexicalEnvironment() {
+        val input = "(let ((x 1)) (eval '(+ x 1)))"
+
+        assertSExpressionsMatch(parseString("2"), evaluateString(input))
+    }
+
+    @Test
+    fun lookupKeywordSymbol() {
+        val symbol = ":symbol"
+
+        assertSExpressionsMatch(parseString(symbol), lookupSymbol(symbol)!!)
+    }
+
+    @Test
+    fun lookupT() {
+        val symbol = "T"
+
+        assertSExpressionsMatch(parseString(symbol), lookupSymbol(symbol)!!)
+    }
+
+    @Test
+    fun lookupNil() {
+        val symbol = "NIL"
+
+        assertSExpressionsMatch(parseString(symbol), lookupSymbol(symbol)!!)
+    }
+
+    @Test
+    fun lookupUndefinedSymbol() {
+        assertThat(Eval.lookupSymbol("undefined")).isNull()
+    }
+
+    @Test
+    fun evalUndefinedFunction() {
+        val input = "(funcall 'eval '(undefined))"
+
+        assertThrows(UndefinedFunctionException::class.java) {
+            evaluateString(input)
+        }
+    }
+
+    @Test
+    fun evalUndefinedSymbol() {
+        val input = "(eval undefined)"
+
+        assertThrows(UndefinedSymbolException::class.java) {
+            evaluateString(input)
+        }
+    }
+
+    @Test
+    fun evalWithDottedLambdaList() {
+        val input = "(funcall 'eval (cons '+ 1))"
+
+        assertThrows(DottedArgumentListException::class.java) {
+            evaluateString(input)
+        }
+    }
+
+    @Test
+    fun evalWithTooManyArguments() {
+        assertThrows(TooManyArgumentsException::class.java) {
+            evaluateString("(eval '1 '2 '3)")
+        }
+    }
+
+    @Test
+    fun evalWithTooFewArguments() {
+        assertThrows(TooFewArgumentsException::class.java) {
+            evaluateString("(eval)")
+        }
+    }
+
+    @Test
+    fun undefinedFunctionException_HasCorrectAttributes() {
+        assertIsErrorWithMessage(UndefinedFunctionException(Nil))
+    }
+
+    @Test
+    fun undefinedSymbolException_HasCorrectAttributes() {
+        assertIsErrorWithMessage(UndefinedSymbolException(Nil))
+    }
+
+    @Test
+    fun evalComma() {
+        val input = ",a"
+
+        assertThrows(UnmatchedCommaException::class.java) {
+            evaluateString(input)
+        }
+    }
+
+    @Test
+    fun evalAtSign() {
+        val input = "@a"
+
+        assertThrows(UnmatchedAtSignException::class.java) {
+            evaluateString(input)
+        }
+    }
+
+    @Test
+    fun evalBackTick() {
+        val input = "`(a b c)"
+
+        assertSExpressionsMatch(parseString("(a b c)"), evaluateString(input))
+    }
+
+    @Test
+    fun evalBackTickWithCommasAndAtSigns() {
+        val input = "(let ((x '(1 2 3)) (y '(4 5 6)) (z 'apple)) `(start ,x ,@y ,z end))"
+
+        assertSExpressionsMatch(parseString("(start (1 2 3) 4 5 6 apple end)"), evaluateString(input))
+    }
+
+    @Test
+    fun evalBackTickOnComma() {
+        val input = "`,9"
+
+        assertSExpressionsMatch(parseString("9"), evaluateString(input))
+    }
+
+    @Test
+    fun evalBackTickOnAtSign() {
+        assertThrows(AtSignNotInCommaException::class.java) {
+            evaluateString("`@9")
+        }
+    }
+
+    @Test
+    fun evalNestedBackquotes() {
+        val input = "`,`,`,`,9"
+
+        assertSExpressionsMatch(parseString("9"), evaluateString(input))
+    }
+
+    @Test
+    fun unmatchedCommaException_HasCorrectAttributes() {
+        assertIsErrorWithMessage(UnmatchedCommaException())
+    }
+
+    @Test
+    fun unmatchedAtSignException_HasCorrectAttributes() {
+        assertIsErrorWithMessage(UnmatchedAtSignException())
+    }
+
+    @Test
+    fun evalQuoteInNestedList() {
+        val input = "(let ((g 27)) `((,g)))"
+
+        assertSExpressionsMatch(parseString("((27))"), evaluateString(input))
+    }
+
+    @Test
+    fun evalAtSignInNestedList() {
+        val input = "(let ((g '(1 2 3))) `((,@g)))"
+
+        assertSExpressionsMatch(parseString("((1 2 3))"), evaluateString(input))
+    }
+
+    @Test
+    fun evalNestedBackquotesInList() {
+        val input = "`(,`(1 ,`2 ,@`(3)))"
+
+        assertSExpressionsMatch(parseString("((1 2 3))"), evaluateString(input))
+    }
+
+    @Test
+    fun scopeRestoredAfterFailure_Let() {
+        evaluateString("(setq n 100)")
+
+        try {
+            evaluateString("(let ((n 200)) (begin 1 2 3 y))")
+            fail("expected exception")
+        } catch (e: UndefinedSymbolException) {
+        }
+
+        assertSExpressionsMatch(parseString("100"), evaluateString("n"))
+    }
+
+    @Test
+    fun scopeRestoredAfterFailure_Defun() {
+        evaluateString("(setq n 100)")
+
+        try {
+            evaluateString("(defun test (n) (begin 1 2 3 y))")
+            evaluateString("(test 200)")
+            fail("expected exception")
+        } catch (e: UndefinedSymbolException) {
+        }
+
+        assertSExpressionsMatch(parseString("100"), evaluateString("n"))
+    }
+
+    @Test
+    fun scopeRestoredAfterFailure_Lambda() {
+        evaluateString("(setq n 100)")
+
+        try {
+            evaluateString("((lambda (n) (begin 1 2 3 y)) 200)")
+            fail("expected exception")
+        } catch (e: UndefinedSymbolException) {
+        }
+
+        assertSExpressionsMatch(parseString("100"), evaluateString("n"))
+    }
+
+    @Test
+    fun scopeRestoredAfterFailure_Recur() {
+        evaluateString("(setq n 100)")
+
+        try {
+            evaluateString("(defun tail-recursive (n) (begin (recur) 2))")
+            evaluateString("(tail-recursive 200)")
+            fail("expected exception")
+        } catch (e: RecurNotInTailPositionException) {
+        }
+
+        assertSExpressionsMatch(parseString("100"), evaluateString("n"))
+    }
+
+    @Test
+    fun scopeRestoredAfterFailure_Apply() {
+        evaluateString("(setq n 100)")
+
+        try {
+            evaluateString("(defun tail-recursive (n) (begin (recur) 2))")
+            evaluateString("(apply 'tail-recursive '(200))")
+            fail("expected exception")
+        } catch (e: RecurNotInTailPositionException) {
+        }
+
+        assertSExpressionsMatch(parseString("100"), evaluateString("n"))
+    }
+}

src/test/kotlin/function/builtin/SETTest.java

@@ -3,7 +3,7 @@ package function.builtin;
 import function.ArgumentValidator.BadArgumentTypeException;
 import function.ArgumentValidator.TooFewArgumentsException;
 import function.ArgumentValidator.TooManyArgumentsException;
-import function.builtin.EVAL.UndefinedSymbolException;
+import function.builtin.Eval.UndefinedSymbolException;
 import org.junit.Test;
 import sexpression.LispNumber;
 import table.SymbolTable;

src/test/kotlin/function/builtin/special/ANDTest.java

@@ -1,6 +1,6 @@
 package function.builtin.special;
 
-import function.builtin.EVAL.UndefinedSymbolException;
+import function.builtin.Eval.UndefinedSymbolException;
 import org.junit.Test;
 import sexpression.LispNumber;
 import testutil.SymbolAndFunctionCleaner;

src/test/kotlin/function/builtin/special/IFTest.java

@@ -2,7 +2,7 @@ package function.builtin.special;
 
 import function.ArgumentValidator.TooFewArgumentsException;
 import function.ArgumentValidator.TooManyArgumentsException;
-import function.builtin.EVAL.UndefinedSymbolException;
+import function.builtin.Eval.UndefinedSymbolException;
 import org.junit.Test;
 import testutil.SymbolAndFunctionCleaner;
 

src/test/kotlin/function/builtin/special/LETTest.java

@@ -4,7 +4,7 @@ import function.ArgumentValidator.BadArgumentTypeException;
 import function.ArgumentValidator.DottedArgumentListException;
 import function.ArgumentValidator.TooFewArgumentsException;
 import function.ArgumentValidator.TooManyArgumentsException;
-import function.builtin.EVAL.UndefinedSymbolException;
+import function.builtin.Eval.UndefinedSymbolException;
 import org.junit.Test;
 import sexpression.Cons;
 import sexpression.LispNumber;

src/test/kotlin/function/builtin/special/LET_STARTest.java

@@ -4,7 +4,7 @@ import function.ArgumentValidator.BadArgumentTypeException;
 import function.ArgumentValidator.DottedArgumentListException;
 import function.ArgumentValidator.TooFewArgumentsException;
 import function.ArgumentValidator.TooManyArgumentsException;
-import function.builtin.EVAL.UndefinedSymbolException;
+import function.builtin.Eval.UndefinedSymbolException;
 import org.junit.Test;
 import sexpression.Cons;
 import sexpression.LispNumber;

src/test/kotlin/function/builtin/special/LambdaTest.kt

@@ -4,7 +4,7 @@ import function.ArgumentValidator.BadArgumentTypeException
 import function.ArgumentValidator.DottedArgumentListException
 import function.ArgumentValidator.TooFewArgumentsException
 import function.ArgumentValidator.TooManyArgumentsException
-import function.builtin.EVAL.UndefinedFunctionException
+import function.builtin.Eval.UndefinedFunctionException
 import function.builtin.special.Lambda.Lambda.createFunction
 import function.builtin.special.Lambda.Lambda.isLambdaExpression
 import org.assertj.core.api.Assertions.assertThat

src/test/kotlin/function/builtin/special/ORTest.java

@@ -1,6 +1,6 @@
 package function.builtin.special;
 
-import function.builtin.EVAL.UndefinedSymbolException;
+import function.builtin.Eval.UndefinedSymbolException;
 import org.junit.Test;
 import sexpression.LispNumber;
 import testutil.SymbolAndFunctionCleaner;

src/test/kotlin/function/builtin/special/SETQTest.java

@@ -3,7 +3,7 @@ package function.builtin.special;
 import function.ArgumentValidator.BadArgumentTypeException;
 import function.ArgumentValidator.TooFewArgumentsException;
 import function.ArgumentValidator.TooManyArgumentsException;
-import function.builtin.EVAL.UndefinedSymbolException;
+import function.builtin.Eval.UndefinedSymbolException;
 import org.junit.Test;
 import sexpression.LispNumber;
 import table.SymbolTable;

src/test/kotlin/testutil/SymbolAndFunctionCleaner.kt

@@ -15,7 +15,7 @@ abstract class SymbolAndFunctionCleaner {
     @Before
     @BeforeEach
     fun setUp() {
-        executionContext.clearContext()
+        ExecutionContext.clearContext()
         FunctionTable.resetFunctionTable()
         additionalSetUp()
     }
@@ -23,7 +23,7 @@ abstract class SymbolAndFunctionCleaner {
     @After
     @AfterEach
     fun tearDown() {
-        executionContext.clearContext()
+        ExecutionContext.clearContext()
         FunctionTable.resetFunctionTable()
         additionalTearDown()
     }

src/test/kotlin/testutil/TestUtilities.kt

@@ -2,7 +2,7 @@ package testutil
 
 import error.LispException
 import error.Severity.ERROR
-import function.builtin.EVAL.eval
+import function.builtin.Eval.Companion.eval
 import org.assertj.core.api.Assertions.assertThat
 import parser.LispParser
 import sexpression.Cons