Correctly convert bignums to strings in YailList (#1546)

Change-Id: Ia3b29e30091e88e1db0fb5ec02c6b0d270c17f15

appinventor/components/src/com/google/appinventor/components/runtime/util/YailList.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -10,6 +10,7 @@ import com.google.appinventor.components.runtime.errors.YailRuntimeError;
 
 import gnu.lists.LList;
 import gnu.lists.Pair;
+import gnu.math.IntNum;
 
 import org.json.JSONException;
 
@@ -119,7 +120,11 @@ public class YailList extends Pair {
    * @return the string
    */
   public static String YailListElementToString(Object element) {
-    if (Number.class.isInstance(element)) {
+    if (element instanceof IntNum) {
+      return ((IntNum) element).toString(10);
+    } else if (element instanceof Long) {
+      return Long.toString((Long) element);
+    } else if (Number.class.isInstance(element)) {
       return YailNumberToString.format(((Number) element).doubleValue());
     } else {
       return String.valueOf(element);

appinventor/components/src/com/google/appinventor/components/runtime/util/YailNumberToString.java

@@ -58,7 +58,7 @@ public final class YailNumberToString {
   public static String format(double number) {
     // We will print integer values without a decimal point.
     if (number == Math.rint(number)) {
-      return String.valueOf((int) number);
+      return String.valueOf((long) number);
     } else {
       double mag = Math.abs(number);
       if (mag < BIGBOUND && mag > SMALLBOUND) {

appinventor/components/tests/com/google/appinventor/components/runtime/util/YailListTest.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
 package com.google.appinventor.components.runtime.util;
 
 import gnu.lists.FString;
+import gnu.math.IntNum;
 
 import junit.framework.TestCase;
 
@@ -203,4 +204,12 @@ public class YailListTest extends TestCase {
       // this is the intended behavior
     }
   }
+
+  public void testBigNumsInStringArray() {
+    YailList list = YailList.makeList(new Object[] { IntNum.make(Long.MAX_VALUE), (Long) Long.MAX_VALUE });
+    String[] strings = list.toStringArray();
+    assertEquals(2, strings.length);
+    assertEquals(Long.toString(Long.MAX_VALUE), strings[0]);
+    assertEquals(Long.toString(Long.MAX_VALUE), strings[1]);
+  }
 }