android_calculator-5: App help

AndroidManifest.xml

@@ -37,6 +37,22 @@
 				  a:label="@string/c_about"
 				  a:configChanges="orientation|keyboardHidden"/>
 
+		<activity a:name=".help.HelpActivity"
+				  a:label="@string/c_help"
+				  a:configChanges="orientation|keyboardHidden"/>
+
+		<activity a:name=".help.HelpFaqActivity"
+				  a:label="@string/c_help"
+				  a:configChanges="orientation|keyboardHidden"/>
+
+		<activity a:name=".help.HelpHintsActivity"
+				  a:label="@string/c_help"
+				  a:configChanges="orientation|keyboardHidden"/>
+
+		<activity a:name=".help.HelpScreensActivity"
+				  a:label="@string/c_help"
+				  a:configChanges="orientation|keyboardHidden"/>
+
 		<activity a:name=".CalculatorFunctionsActivity"
 				  a:label="@string/c_functions"
 				  a:configChanges="orientation|keyboardHidden">

res/layout/about.xml

@@ -21,7 +21,7 @@
 
 	<TextView
 			a:id="@+id/aboutTextView"
-			a:text="@string/c_copyright"
+			a:text="@string/c_about_content"
 			a:layout_height="fill_parent"
 			a:layout_width="fill_parent"
 			a:layout_gravity="top|center_horizontal"

res/layout/calc_five_digit_button.xml

@@ -9,7 +9,7 @@
 													   xmlns:calc="http://schemas.android.com/apk/res/org.solovyev.android.calculator"
 													   a:id="@+id/fiveDigitButton"
 													   a:text="5"
-													   calc:textUp="cosh"
+													   calc:textUp="t"
-													   calc:textDown="acosh"
+													   calc:textDown="j"
 													   style="?digitButtonStyle"
 													   a:onClick="digitButtonClickHandler"/>

res/layout/calc_four_digit_button.xml

@@ -9,7 +9,7 @@
 													   xmlns:calc="http://schemas.android.com/apk/res/org.solovyev.android.calculator"
 													   a:id="@+id/fourDigitButton"
 													   a:text="4"
-													   calc:textUp="sinh"
+													   calc:textUp="x"
-													   calc:textDown="asinh"
+													   calc:textDown="y"
 													   style="?digitButtonStyle"
 													   a:onClick="digitButtonClickHandler"/>

res/layout/help.xml

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<!--
+  ~ Copyright (c) 2009-2011. Created by serso aka se.solovyev.
+  ~ For more information, please, contact se.solovyev@gmail.com
+  ~ or visit http://se.solovyev.org
+  -->
+
+<TabHost xmlns:a="http://schemas.android.com/apk/res/android"
+		 a:id="@android:id/tabhost"
+		 a:layout_width="fill_parent"
+		 a:layout_height="fill_parent">
+
+	<LinearLayout
+			a:orientation="vertical"
+			a:layout_width="fill_parent"
+			a:layout_height="fill_parent">
+
+		<TabWidget
+				a:id="@android:id/tabs"
+				a:layout_width="fill_parent"
+				a:layout_height="wrap_content"/>
+
+		<FrameLayout
+				a:id="@android:id/tabcontent"
+				a:layout_width="fill_parent"
+				a:layout_height="fill_parent"/>
+
+	</LinearLayout>
+</TabHost>

res/layout/help_faq.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<!--
+  ~ Copyright (c) 2009-2011. Created by serso aka se.solovyev.
+  ~ For more information, please, contact se.solovyev@gmail.com
+  ~ or visit http://se.solovyev.org
+  -->
+
+
+<ScrollView xmlns:a="http://schemas.android.com/apk/res/android"
+			a:layout_width="fill_parent"
+			a:layout_height="fill_parent">
+
+	<TextView
+			a:text="@string/c_faq_content"
+			a:layout_width="fill_parent"
+			a:layout_height="fill_parent"
+			a:gravity="top|left"
+			a:layout_weight="1"
+			a:scrollbars="vertical"
+			style="@style/about_style"/>
+
+</ScrollView>
+

res/layout/help_hints.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<!--
+  ~ Copyright (c) 2009-2011. Created by serso aka se.solovyev.
+  ~ For more information, please, contact se.solovyev@gmail.com
+  ~ or visit http://se.solovyev.org
+  -->
+<ScrollView xmlns:a="http://schemas.android.com/apk/res/android"
+			a:layout_width="fill_parent"
+			a:layout_height="fill_parent">
+
+	<TextView
+			xmlns:a="http://schemas.android.com/apk/res/android"
+			a:text="@string/c_hints_content"
+			a:gravity="top|left"
+			a:layout_weight="1"
+			a:scrollbars="vertical"
+			style="@style/about_style"/>
+
+</ScrollView>

res/layout/help_screens.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<!--
+  ~ Copyright (c) 2009-2011. Created by serso aka se.solovyev.
+  ~ For more information, please, contact se.solovyev@gmail.com
+  ~ or visit http://se.solovyev.org
+  -->
+<ScrollView xmlns:a="http://schemas.android.com/apk/res/android"
+			a:layout_width="fill_parent"
+			a:layout_height="fill_parent">
+
+	<TextView
+			xmlns:a="http://schemas.android.com/apk/res/android"
+			a:text="@string/c_screens_content"
+			a:gravity="top|left"
+			a:layout_weight="1"
+			a:scrollbars="vertical"
+			style="@style/about_style"/>
+
+</ScrollView>

res/menu/main_menu.xml

@@ -8,6 +8,9 @@
 	<item a:id="@+id/main_menu_item_history"
 		  a:title="@string/c_history"/>
 
+	<item a:id="@+id/main_menu_item_help"
+		  a:title="@string/c_help"/>
+
 	<item a:id="@+id/main_menu_item_about"
 		  a:title="@string/c_about"/>
 

res/values-ru/strings.xml

@@ -22,7 +22,7 @@
 	<string name="c_restart">Перезапуск</string>
 
 	<!--ABOUT ACTIVITY-->
-	<string name="c_copyright">Copyright (c) 2009-2011\n\n<b>Программа создана\nserso aka se.solovyev</b>\n\n
+	<string name="c_about_content">Copyright (c) 2009-2011\n\n<b>Программа создана\nserso aka se.solovyev</b>\n\n
 		Эта программа с открытыми исходным кодом:\nон может быть найден на \n<a href="https://github.com/serso/android_calculator">http://github.com</a>\n\n
 		За подробной информацией, пожалуйста,\nобращайтесь на почту\n<a href="mailto:se.solovyev@gmail.com">se.solovyev@gmail.com</a>\n
 		или посетите сайт \n<a href="http://se.solovyev.org">http://se.solovyev.org</a>\n\n
@@ -154,4 +154,100 @@
 	<string name="c_op_description_integral">Возвращает интеграл функции \'f(x)\' по переменно \'x\'.</string>
 	<string name="c_op_description_integral_ab">Интегрирует функцию \'f(x)\' по переменной \'x\' от \'a\' до \'b\'.</string>
 
+	<string name="c_pf_description_factorial">Возвращает факториал от предыдущего выражения.</string>
+	<string name="c_pf_description_percent" formatted="false">Возвращает процентное значение от предыдущего выражения.\nПримеры:\n
+		100 + 50% = 150\n
+		100 * 50% = 50\n
+		100 + 100 * 50% * 50% = 125
+	</string>
+	<string name="c_pf_description_degree">Преобразует градусы в радианы.\n
+		Примеры:\n
+		268° = 4.67748\n
+		30.21° = 0.52726
+	</string>
+
+	<string name="c_faq">FAQ</string>
+	<string name="c_hints">Подсказки</string>
+	<string name="c_screens">Экраны</string>
+
+	<string name="c_faq_content" formatted="false">
+<b>Как я могу использовать функции написанные в верхнем правом и нижнем правом углах кнопки?</b>\n
+\n
+Нажмите на кнопку и потяните вверх или вниз. В зависимости от значения указанного на кнопке произойдёт действие.\n
+\n
+<b>Как я могу переключиться между радианами и градусами?</b>\n
+\n
+На данный момент К++ не поддерживает такого переключения, но вы можете использовать функции deg() и rad() или опертор ° для переода радиан в градусы и наоборот.\n
+\n
+<b>Примеры:</b>\n
+268° = 4.67748\n
+30.21° = 0.52726\n
+rad(30, 21, 0) = 0.52726\n
+deg(4.67748) = 268\n
+\n
+<b>Поддерживает ли К++ проценты?</b>\n
+\n
+Да, функция % может быть найдена в правом верхнем углу кнопки /.\n
+\n
+<b>Примеры:</b>\n
+\n
+100 + 50% = 150\n
+100 * 50% = 50\n
+100 + 100 * 50% * 50% = 125\n
+100 + (100 * 50% * (25 + 25)% + 100%) = 150\n
+\n
+<b>Замечание:</b>\n
+\n
+100 + (20 + 20)% = 140, <b>но</b> 100+  (20% + 20%) = 124.0\n
+100 + 50% ^ 2 = 2600, <b>но</b> 100 + 50 ^ 2% = 101.08\n
+\n
+<b>Поддерживает ли К++ дробные вычисления?</b>\n
+\n
+Да, вы можете ввести дробное выражение в редактор и нажать ≡ (в правом верхнем углу кнопки =). Также вы можете использовать ≡ для упрощения выражений.\n
+\n
+<b>Примеры:</b>\n
+\n
+2/3 + 5/9 ≡ 11/9\n
+2/9 + 3/123 ≡ 91/369\n
+(6 - t) ^ 3 ≡ 216 - 108t + 18t ^ 2 - t ^ 3\n
+\n
+<b>Поддерживает ли К++ комплексные вычисления?</b>\n
+\n
+Да, просто введите комплексное выражение (используя i или √(-1) в качестве мнимого числа).\n
+\n
+<b>Примеры:</b>\n
+\n
+(2i + 1) ^ = -3 + 4i\n
+e ^ i = 0.5403 + 0.84147i\n
+\n
+<b>Умеет ли К++ рисовать графики функций?</b>\n
+\n
+Нет.\n
+\n
+<b>Поддерживает ли К++ матричные вычисления?</b>\n
+\n
+Нет.\n
+\n
+<b>Почему я получаю 1.76732452452345E-17 вместо 0?</b>\n
+\n
+Проверьте опцию \'Округление результата\' в настройках приложения - она должно быть включена.\n
+	</string>
+
+		<string name="c_hints_content">
+			1. Вы можете опускать ненужные знаки произведения в выражении (вместо 3*t или t*sin(π*t) просто пишите 3t или tsin(πt)).\n\n
+2. Используйте ≡ (в верхнем правом углу кнопки =) для упрощения выражения.\n\n
+3. Нажмите на результат для того, чтобы скопировать его в буфер обмена.\n\n
+4. Используйте кнопку = реже - результат вычисляется на лету.\n\n
+4. Создайте константы для часто используемых значений (таким образом вы можете даже сохранять выражения)
+	</string>
+
+	<string name="c_screens_content">
+		1. <b>Основной экран:</b> открывается по старту приложения, на него можно попасть из любого другого экрана нажав кнопку Назад.\n\n
+2. <b>Экран констант и переменных:</b> содержит список переменных и констант. Пользователь может добавить новые элементы нажав кнопку Добавить. Короткое нажатие вставляет значение в редактор, длинное - открывает окно редактирования. На экран можно попасть нажав кнопку π,… на основном экране.\n\n
+3. <b>Экран функций:</b> содержит список всех доступных функций. Короткое нажатие вставляет функцию в редактор. На экран можно попасть нажав кнопку f(x) на основном экране.\n\n
+4. <b>Экран операторов:</b> содержит список всех доступных операторов. Короткое нажатие вставляет оператор в редактор. На экран можно попасть нажав кнопку ∂,… на основном экране.\n\n
+5. <b>Экран истории:</b> содержит список всех операций произведённых пользователем.  Короткое нажатие на элемент списка вставляет его в редактор. На экран можно попасть нажав кнопку M на основном экране.\n\n
+6. <b>Экран настроек:</b> содержит список настроек приложения. На экран можно попасть нажав кнопку Настройки в меню.
+			</string>
+
 </resources>

res/values/strings.xml

@@ -23,7 +23,7 @@
 	<string name="c_restart">Restart</string>
 
 	<!--ABOUT ACTIVITY-->
-	<string name="c_copyright">Copyright (c) 2009-2011\n\n<b>Created by serso aka se.solovyev</b>\n\n
+	<string name="c_about_content">Copyright (c) 2009-2011\n\n<b>Created by serso aka se.solovyev</b>\n\n
 		This program is open source:\nall source code can be found on\n<a href="https://github.com/serso/android_calculator">http://github.com</a>\n\n
 		For more information please\ncontact the author by email\n<a href="mailto:se.solovyev@gmail.com">se.solovyev@gmail.com</a>
 		\nor visit\n<a href="http://se.solovyev.org">http://se.solovyev.org</a>\n\n
@@ -155,5 +155,102 @@
 	<string name="c_op_description_integral">Gives integral of function \'f(x)\' by \'x\' variable.</string>
 	<string name="c_op_description_integral_ab">Integrates function \'f(x)\' by \'x\' variable from \'a\' to \'b\'.</string>
 
+	<string name="c_pf_description_factorial">Gives the factorial for expression before.</string>
+	<string name="c_pf_description_percent" formatted="false">Gives the percent value for expression
+		before.\nExamples:\n
+		100 + 50% = 150\n
+		100 * 50% = 50\n
+		100 + 100 * 50% * 50% = 125
+	</string>
+	<string name="c_pf_description_degree">Converts degrees to radians.\n
+		Examples:\n
+		268° = 4.67748\n
+		30.21° = 0.52726
+	</string>
+
+	<string name="c_faq">FAQ</string>
+	<string name="c_hints">Hints</string>
+	<string name="c_screens">Screens</string>
+
+	<string name="c_faq_content" formatted="false">
+<b>How can I use functions written in the top right and bottom right corners of the button?</b>\n
+\n
+Push the button and slide lightly up or down. Depending on value showed on the button action will occur.\n
+\n
+<b>How can I toggle between radians and degrees?</b>\n
+\n
+Currently C++ doesn\'t support this feature but you can use deg() and rad() functions and ° operator to convert degrees to radians and vice versa.\n
+\n
+<b>Examples:</b>\n
+268° = 4.67748\n
+30.21° = 0.52726\n
+rad(30, 21, 0) = 0.52726\n
+deg(4.67748) = 268\n
+\n
+<b>Does C++ support %?</b>\n
+\n
+Yes, % function can be found in the top right corner of / button.\n
+\n
+<b>Examples:</b>\n
+\n
+100 + 50% = 150\n
+100 * 50% = 50\n
+100 + 100 * 50% * 50% = 125\n
+100 + (100 * 50% * (25 + 25)% + 100%) = 150\n
+\n
+<b>Note:</b>\n
+\n
+100 + (20 + 20)% = 140, <b>but</b> 100+  (20% + 20%) = 124.0\n
+100 + 50% ^ 2 = 2600, <b>but</b> 100 + 50 ^ 2% = 101.08\n
+\n
+<b>Does C++ support fractional calculations?</b>\n
+\n
+Yes, you can type your fractional expression in the editor and use ≡ (in the top right corner of = button). Also you can use ≡ to simplify expression.\n
+\n
+<b>Examples:</b>\n
+\n
+2/3 + 5/9 ≡ 11/9\n
+2/9 + 3/123 ≡ 91/369\n
+(6 - t) ^ 3 ≡ 216 - 108t + 18t ^ 2 - t ^ 3\n
+\n
+<b>Does C++ support complex calculations?</b>\n
+\n
+Yes, just enter complex expression (using i or √(-1) as imaginary number).\n
+\n
+<b>Examples:</b>\n
+\n
+(2i + 1) ^ = -3 + 4i\n
+e ^ i = 0.5403 + 0.84147i\n
+\n
+<b>Can C++ plot graph of the function?</b>\n
+\n
+No, currently C++ cannot plot functions\' graphs.\n
+\n
+<b>Does C++ support matrix calculations?</b>\n
+\n
+No, it doesn\'t.\n
+\n
+<b>Why I\'ve got 1.76732452452345E-17 instead of 0?</b>\n
+\n
+Check the \'Round result\' preference in application settings - it should be turned on.\n</string>
+
+	<string name="c_hints_content">
+	1. You can omit unnecessary multiplication signs (instead of 3*t or t*sin(π*t) just type 3t or tsin(πt))\n\n
+2. Use ≡ (in the top right corner of = button) to simplify expression\n\n
+3. Just click on the result to copy it to the clipboard\n\n
+4. Use = button seldom - result is calculating on the fly\n\n
+4. Add constants for often used values (you can even save expressions)\n\n
+	</string>
+
+	<string name="c_screens_content">
+		1. <b>Main screen:</b> is shown on application start, can be reached from another screen by pressing Back button.\n\n
+2. <b>Variables and Constants screen:</b> contains list of available constants. User may add some constants and variables here by clicking Add button. Short click on variable/constant inserts it into the editor, long click - opens variable editor window. Can be reached from the main screen by pressing π,… button.\n\n
+3. <b>Functions screen:</b> contains list of all available functions. Short click on function inserts it into the editor. Can be reached from the main screen by pressing f(x) button.\n\n
+4. <b>Operators screen:</b> contains list of all available operators. Short click on operator inserts it into the editor. Can be reached from the main screen by pressing ∂,… button.\n\n
+5. <b>History screen:</b> contains list of all actions done by user.  Short click on history item sets it into the editor. Can be reached from the main screen by pressing M button.\n\n
+6. <b>Settings screen:</b> contains application preferences. Can be reached from the main screen by pressing Settings in menu.
+			</string>
+
+
 
 </resources>

src/main/java/org/solovyev/android/calculator/CalculatorActivity.java

@@ -415,6 +415,10 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 				CalculatorActivityLauncher.showAbout(this);
 				result = true;
 				break;
+			case R.id.main_menu_item_help:
+				CalculatorActivityLauncher.showHelp(this);
+				result = true;
+				break;
 			case R.id.main_menu_item_exit:
 				this.finish();
 				result = true;

src/main/java/org/solovyev/android/calculator/CalculatorActivityLauncher.java

@@ -4,6 +4,7 @@ import android.content.Context;
 import android.content.Intent;
 import android.widget.Toast;
 import org.jetbrains.annotations.NotNull;
+import org.solovyev.android.calculator.help.HelpActivity;
 import org.solovyev.common.utils.StringUtils;
 
 /**
@@ -17,6 +18,10 @@ public class CalculatorActivityLauncher {
 		context.startActivity(new Intent(context, CalculatorHistoryActivity.class));
 	}
 
+	public static void showHelp(@NotNull final Context context) {
+		context.startActivity(new Intent(context, HelpActivity.class));
+	}
+
 	public static void showSettings(@NotNull final Context context) {
 		context.startActivity(new Intent(context, CalculatorPreferencesActivity.class));
 	}

src/main/java/org/solovyev/android/calculator/CalculatorOperatorsActivity.java

@@ -10,7 +10,6 @@ import android.widget.AdapterView;
 import android.widget.ArrayAdapter;
 import android.widget.ListView;
 import android.widget.TextView;
-import jscl.math.function.Function;
 import jscl.math.operator.Operator;
 import org.jetbrains.annotations.NotNull;
 import org.solovyev.android.calculator.model.CalculatorEngine;
@@ -37,7 +36,10 @@ public class CalculatorOperatorsActivity extends ListActivity {
 
 		setContentView(R.layout.operators);
 
-		adapter = new OperatorsArrayAdapter(this, R.layout.var, R.id.var_text, new ArrayList<Operator>(CalculatorEngine.instance.getOperatorsRegistry().getEntities()));
+		List<Operator> elements = new ArrayList<Operator>();
+		elements.addAll(CalculatorEngine.instance.getOperatorsRegistry().getEntities());
+		elements.addAll(CalculatorEngine.instance.getPostfixFunctionsRegistry().getEntities());
+		adapter = new OperatorsArrayAdapter(this, R.layout.var, R.id.var_text, elements);
 		setListAdapter(adapter);
 
 		final ListView lv = getListView();
@@ -82,7 +84,11 @@ public class CalculatorOperatorsActivity extends ListActivity {
 
 			final Operator operator = getItem(position);
 
-			final String operatorDescription = CalculatorEngine.instance.getOperatorsRegistry().getDescription(getContext(), operator.getName());
+			String operatorDescription = CalculatorEngine.instance.getOperatorsRegistry().getDescription(getContext(), operator.getName());
+			if (StringUtils.isEmpty(operatorDescription)) {
+				operatorDescription = CalculatorEngine.instance.getPostfixFunctionsRegistry().getDescription(getContext(), operator.getName());
+			}
+
 			if (!StringUtils.isEmpty(operatorDescription)) {
 				TextView description = (TextView) result.findViewById(R.id.var_description);
 				if (description == null) {

src/main/java/org/solovyev/android/calculator/help/HelpActivity.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2009-2011. Created by serso aka se.solovyev.
+ * For more information, please, contact se.solovyev@gmail.com
+ * or visit http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator.help;
+
+import android.app.Activity;
+import android.app.TabActivity;
+import android.content.Intent;
+import android.os.Bundle;
+import android.widget.TabHost;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.solovyev.android.calculator.R;
+
+/**
+ * User: serso
+ * Date: 11/19/11
+ * Time: 11:35 AM
+ */
+public class HelpActivity extends TabActivity {
+
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+
+		setContentView(R.layout.help);
+
+		final TabHost tabHost = getTabHost();
+
+		createTab(tabHost, "faq", "Faq", HelpFaqActivity.class);
+		createTab(tabHost, "hints", "Hints", HelpHintsActivity.class);
+		createTab(tabHost, "screens", "Screens", HelpScreensActivity.class);
+
+		tabHost.setCurrentTab(0);
+
+
+	}
+
+	private void createTab(@NotNull TabHost tabHost,
+						   @NotNull String tabId,
+						   @NotNull String tabCaption,
+						   @NotNull Class<? extends Activity> activityClass) {
+
+		TabHost.TabSpec spec;
+
+		final Intent intent = new Intent().setClass(this, activityClass);
+
+		// Initialize a TabSpec for each tab and add it to the TabHost
+		spec = tabHost.newTabSpec(tabId).setIndicator(tabCaption)
+				.setContent(intent);
+
+		tabHost.addTab(spec);
+	}
+}

src/main/java/org/solovyev/android/calculator/help/HelpFaqActivity.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2009-2011. Created by serso aka se.solovyev.
+ * For more information, please, contact se.solovyev@gmail.com
+ * or visit http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator.help;
+
+import android.app.Activity;
+import android.os.Bundle;
+import org.jetbrains.annotations.Nullable;
+import org.solovyev.android.calculator.R;
+
+/**
+ * User: serso
+ * Date: 11/19/11
+ * Time: 11:37 AM
+ */
+public class HelpFaqActivity extends Activity {
+
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+
+		setContentView(R.layout.help_faq);
+	}
+}

src/main/java/org/solovyev/android/calculator/help/HelpHintsActivity.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2009-2011. Created by serso aka se.solovyev.
+ * For more information, please, contact se.solovyev@gmail.com
+ * or visit http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator.help;
+
+import android.app.Activity;
+import android.os.Bundle;
+import org.jetbrains.annotations.Nullable;
+import org.solovyev.android.calculator.R;
+
+/**
+ * User: serso
+ * Date: 11/19/11
+ * Time: 11:37 AM
+ */
+public class HelpHintsActivity extends Activity {
+
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+	super.onCreate(savedInstanceState);
+
+		setContentView(R.layout.help_hints);
+	}
+}

src/main/java/org/solovyev/android/calculator/help/HelpScreensActivity.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2009-2011. Created by serso aka se.solovyev.
+ * For more information, please, contact se.solovyev@gmail.com
+ * or visit http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator.help;
+
+import android.app.Activity;
+import android.os.Bundle;
+import org.jetbrains.annotations.Nullable;
+import org.solovyev.android.calculator.R;
+
+/**
+ * User: serso
+ * Date: 11/19/11
+ * Time: 11:38 AM
+ */
+public class HelpScreensActivity extends Activity {
+
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+
+		setContentView(R.layout.help_screens);
+	}
+}

src/main/java/org/solovyev/android/calculator/model/AndroidFunctionsMathRegistry.java

@@ -7,7 +7,6 @@
 package org.solovyev.android.calculator.model;
 
 import org.jetbrains.annotations.NotNull;
-import org.solovyev.common.math.MathEntity;
 import org.solovyev.common.math.MathRegistry;
 
 import java.util.HashMap;
@@ -18,7 +17,7 @@ import java.util.Map;
  * Date: 11/17/11
  * Time: 11:28 PM
  */
-public class AndroidFunctionsMathRegistry<T extends MathEntity> extends AndroidMathRegistryImpl<T> {
+public class AndroidFunctionsMathRegistry extends AndroidMathRegistryImpl<jscl.math.function.Function> {
 
 	@NotNull
 	private static final Map<String, String> substitutes = new HashMap<String, String>();
@@ -29,7 +28,7 @@ public class AndroidFunctionsMathRegistry<T extends MathEntity> extends AndroidM
 	@NotNull
 	private static final String FUNCTION_DESCRIPTION_PREFIX = "c_fun_description_";
 
-	public AndroidFunctionsMathRegistry(@NotNull MathRegistry<T> functionsRegistry) {
+	public AndroidFunctionsMathRegistry(@NotNull MathRegistry<jscl.math.function.Function> functionsRegistry) {
 		super(functionsRegistry, FUNCTION_DESCRIPTION_PREFIX);
 	}
 

src/main/java/org/solovyev/android/calculator/model/AndroidMathRegistryImpl.java

@@ -53,7 +53,6 @@ public abstract class AndroidMathRegistryImpl<T extends MathEntity> implements A
 		if (substitute == null) {
 			stringId = stringsCache.get(prefix + name);
 		} else {
-			// todo serso: think
 			stringId = stringsCache.get(prefix + substitute);
 		}
 

src/main/java/org/solovyev/android/calculator/model/AndroidOperatorsMathRegistry.java

@@ -6,8 +6,8 @@
 
 package org.solovyev.android.calculator.model;
 
+import jscl.math.operator.Operator;
 import org.jetbrains.annotations.NotNull;
-import org.solovyev.common.math.MathEntity;
 import org.solovyev.common.math.MathRegistry;
 
 import java.util.HashMap;
@@ -18,7 +18,7 @@ import java.util.Map;
  * Date: 11/17/11
  * Time: 11:29 PM
  */
-public class AndroidOperatorsMathRegistry<T extends MathEntity> extends AndroidMathRegistryImpl<T> {
+public class AndroidOperatorsMathRegistry extends AndroidMathRegistryImpl<Operator> {
 
 	@NotNull
 	private static final Map<String, String> substitutes = new HashMap<String, String>();
@@ -34,7 +34,7 @@ public class AndroidOperatorsMathRegistry<T extends MathEntity> extends AndroidM
 	@NotNull
 	private static final String OPERATOR_DESCRIPTION_PREFIX = "c_op_description_";
 
-	protected AndroidOperatorsMathRegistry(@NotNull MathRegistry<T> functionsRegistry) {
+	protected AndroidOperatorsMathRegistry(@NotNull MathRegistry<Operator> functionsRegistry) {
 		super(functionsRegistry, OPERATOR_DESCRIPTION_PREFIX);
 	}
 

src/main/java/org/solovyev/android/calculator/model/AndroidPostfixFunctionsRegistry.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2009-2011. Created by serso aka se.solovyev.
+ * For more information, please, contact se.solovyev@gmail.com
+ * or visit http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator.model;
+
+import jscl.math.operator.Operator;
+import org.jetbrains.annotations.NotNull;
+import org.solovyev.common.math.MathRegistry;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * User: serso
+ * Date: 11/19/11
+ * Time: 1:48 PM
+ */
+public class AndroidPostfixFunctionsRegistry extends AndroidMathRegistryImpl<Operator> {
+
+	@NotNull
+	private static final Map<String, String> substitutes = new HashMap<String, String>();
+	static {
+		substitutes.put("%", "percent");
+		substitutes.put("!", "factorial");
+		substitutes.put("°", "degree");
+	}
+
+	@NotNull
+	private static final String POSTFIX_FUNCTION_DESCRIPTION_PREFIX = "c_pf_description_";
+
+	protected AndroidPostfixFunctionsRegistry(@NotNull MathRegistry<Operator> functionsRegistry) {
+		super(functionsRegistry, POSTFIX_FUNCTION_DESCRIPTION_PREFIX);
+	}
+
+
+	@NotNull
+	@Override
+	protected Map<String, String> getSubstitutes() {
+		return substitutes;
+	}
+}

src/main/java/org/solovyev/android/calculator/model/AndroidVarsRegistryImpl.java

@@ -102,6 +102,11 @@ class AndroidVarsRegistryImpl implements AndroidVarsRegistry {
 			add(builder);
 		}
 
+		tryToAddAuxVar("x");
+		tryToAddAuxVar("y");
+		tryToAddAuxVar("t");
+		tryToAddAuxVar("j");
+
 
 		/*Log.d(AndroidVarsRegistry.class.getName(), vars.size() + " variables registered!");
 		for (Var var : vars) {
@@ -109,6 +114,12 @@ class AndroidVarsRegistryImpl implements AndroidVarsRegistry {
 		}*/
 	}
 
+	private void tryToAddAuxVar(@NotNull String name) {
+		if ( !contains(name) ) {
+			add(new Var.Builder(name, (String)null));
+		}
+	}
+
 	private Var.Builder createBuilder(@NotNull String varName, @NotNull String varValue) {
 		final Var.Builder result;
 

src/main/java/org/solovyev/android/calculator/model/CalculatorEngine.java

@@ -9,6 +9,7 @@ import android.content.Context;
 import android.content.SharedPreferences;
 import jscl.JsclMathEngine;
 import jscl.MathEngine;
+import jscl.math.function.Function;
 import jscl.math.operator.Operator;
 import jscl.text.ParseInterruptedException;
 import org.jetbrains.annotations.NotNull;
@@ -16,7 +17,6 @@ import org.jetbrains.annotations.Nullable;
 import org.solovyev.android.calculator.jscl.JsclOperation;
 import org.solovyev.android.msg.AndroidMessage;
 import org.solovyev.common.NumberMapper;
-import org.solovyev.common.math.MathRegistry;
 import org.solovyev.common.msg.MessageRegistry;
 import org.solovyev.common.utils.MutableObject;
 import org.solovyev.common.utils.StringUtils;
@@ -64,12 +64,12 @@ public enum CalculatorEngine {
 	private final AndroidVarsRegistry varsRegister = new AndroidVarsRegistryImpl(engine.getConstantsRegistry());
 
 	@NotNull
-	private final AndroidMathRegistry functionsRegistry = new AndroidFunctionsMathRegistry(engine.getFunctionsRegistry());
+	private final AndroidMathRegistry<jscl.math.function.Function> functionsRegistry = new AndroidFunctionsMathRegistry(engine.getFunctionsRegistry());
 
 	@NotNull
-	private final AndroidMathRegistry operatorsRegistry = new AndroidOperatorsMathRegistry(engine.getOperatorsRegistry());
+	private final AndroidMathRegistry<Operator> operatorsRegistry = new AndroidOperatorsMathRegistry(engine.getOperatorsRegistry());
 
-	private final MathRegistry<Operator> postfixFunctionsRegistry = engine.getPostfixFunctionsRegistry();
+	private final AndroidMathRegistry<Operator> postfixFunctionsRegistry = new AndroidPostfixFunctionsRegistry(engine.getPostfixFunctionsRegistry());
 
 	@NotNull
 	private DecimalFormatSymbols decimalGroupSymbols = new DecimalFormatSymbols(Locale.getDefault());
@@ -294,17 +294,17 @@ public enum CalculatorEngine {
 	}
 
 	@NotNull
-	public AndroidMathRegistry getFunctionsRegistry() {
+	public AndroidMathRegistry<Function> getFunctionsRegistry() {
 		return functionsRegistry;
 	}
 
 	@NotNull
-	public AndroidMathRegistry getOperatorsRegistry() {
+	public AndroidMathRegistry<Operator> getOperatorsRegistry() {
 		return operatorsRegistry;
 	}
 
 	@NotNull
-	public MathRegistry<Operator> getPostfixFunctionsRegistry() {
+	public AndroidMathRegistry<Operator> getPostfixFunctionsRegistry() {
 		return postfixFunctionsRegistry;
 	}