highlighting in editor + refactor

res/layout-land/main.xml

@@ -15,7 +15,7 @@
 
 		<LinearLayout a:layout_weight="2" a:layout_width="match_parent" a:layout_height="0dp">
 
-			<org.solovyev.android.calculator.CalculatorEditText
+			<org.solovyev.android.calculator.CalculatorEditor
 					a:id="@+id/editText"
 					style="@style/display_style"
 					a:inputType="textMultiLine"

res/layout-port/main.xml

@@ -15,7 +15,7 @@
 
 		<LinearLayout a:layout_weight="2" a:layout_width="match_parent" a:layout_height="0dp">
 
-			<org.solovyev.android.calculator.CalculatorEditText
+			<org.solovyev.android.calculator.CalculatorEditor
 					a:id="@+id/editText"
 					style="@style/display_style"
 					a:inputType="textMultiLine"

res/layout/var_edit.xml

@@ -26,6 +26,7 @@
 		<EditText a:id="@+id/var_edit_name"
 				  a:layout_width="match_parent"
 				  a:layout_height="wrap_content"
+				  a:digits="abcdefghijklmnopqrstuvwxyz1234567890"
 				  a:textSize="20dp">
 		</EditText>
 

res/values/strings.xml

@@ -31,7 +31,7 @@
 	<string name="c_paste">paste</string>
 	<string name="c_vars">vars</string>
 
-	<string name="c_calc_color_display_title">Color expressions</string>
+	<string name="c_calc_color_display_title">Highlight expressions</string>
 	<string name="p_calc_result_precision_title">Precision of result</string>
 	<string name="c_exit">Exit</string>
 	<string name="c_add">Add</string>
@@ -43,7 +43,7 @@
 	<string name="c_var_removal_confirmation">Removal confirmation</string>
 	<string name="c_var_removal_confirmation_question">Do you really want to delete \'%s\' variable?</string>
 	<string name="c_var_name">Name</string>
-	<string name="c_var_value">value</string>
+	<string name="c_var_value">Value</string>
 	<string name="c_var_description">Description</string>
 	<string name="c_var_create_var">Create variable</string>
 	<string name="c_var_edit_var">Edit variable</string>

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

@@ -283,7 +283,7 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 
 		final Boolean colorExpressionsInBracketsDefault = new BooleanMapper().parseValue(this.getString(R.string.p_calc_color_display));
 		assert colorExpressionsInBracketsDefault != null;
-		this.calculatorView.getEditor().setHighlightExpressionInBrackets(sharedPreferences.getBoolean(this.getString(R.string.p_calc_color_display_key), colorExpressionsInBracketsDefault));
+		this.calculatorView.getEditor().setHighlightText(sharedPreferences.getBoolean(this.getString(R.string.p_calc_color_display_key), colorExpressionsInBracketsDefault));
 
 		this.calculatorView.evaluate();
 	}

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

@@ -1,131 +0,0 @@
-/*
- * Copyright (c) 2009-2011. Created by serso aka se.solovyev.
- * For more information, please, contact se.solovyev@gmail.com
- */
-
-package org.solovyev.android.calculator;
-
-import android.content.Context;
-import android.content.res.ColorStateList;
-import android.graphics.Color;
-import android.text.Html;
-import android.util.AttributeSet;
-import android.util.Log;
-import android.widget.EditText;
-import org.jetbrains.annotations.NotNull;
-import org.solovyev.android.calculator.math.MathEntityType;
-
-/**
- * User: serso
- * Date: 9/17/11
- * Time: 12:25 AM
- */
-public class CalculatorEditText extends EditText {
-
-	private boolean highlightExpressionInBrackets = true;
-
-	public CalculatorEditText(Context context) {
-		super(context);
-	}
-
-	public CalculatorEditText(Context context, AttributeSet attrs) {
-		super(context, attrs);
-	}
-
-	public CalculatorEditText(Context context, AttributeSet attrs, int defStyle) {
-		super(context, attrs, defStyle);
-	}
-
-	@Override
-	public void setTextColor(ColorStateList colors) {
-		super.setTextColor(colors);	//To change body of overridden methods use File | Settings | File Templates.
-	}
-
-	public void redraw() {
-		String text = getText().toString();
-
-		int selectionStart = getSelectionStart();
-		int selectionEnd = getSelectionEnd();
-
-		if (highlightExpressionInBrackets) {
-
-			int maxNumberOfOpenGroupSymbols = 0;
-			int numberOfOpenGroupSymbols = 0;
-			for (int i = 0; i < text.length(); i++) {
-				char ch = text.charAt(i);
-				if (MathEntityType.openGroupSymbols.contains(ch)) {
-					numberOfOpenGroupSymbols++;
-					maxNumberOfOpenGroupSymbols = Math.max(maxNumberOfOpenGroupSymbols, numberOfOpenGroupSymbols);
-				} else if (MathEntityType.closeGroupSymbols.contains(ch)) {
-					numberOfOpenGroupSymbols--;
-				}
-			}
-
-			if (maxNumberOfOpenGroupSymbols > 0) {
-
-				final StringBuilder sb = new StringBuilder();
-
-				processGroup(sb, text, 0, 0, maxNumberOfOpenGroupSymbols);
-
-				Log.d(CalculatorEditText.class.getName(), sb.toString());
-
-				super.setText(Html.fromHtml(sb.toString()), BufferType.EDITABLE);
-			} else {
-				super.setText(text, BufferType.EDITABLE);
-			}
-		} else {
-			super.setText(text, BufferType.EDITABLE);
-		}
-
-		setSelection(selectionStart, selectionEnd);
-	}
-
-	private int processGroup(@NotNull StringBuilder result, @NotNull String s, int i, int numberOfOpenings, int maxNumberOfGroups) {
-
-		result.append("<font color=\"").append(getColor(maxNumberOfGroups, numberOfOpenings)).append("\">");
-
-		for (; i < s.length(); i++) {
-			char ch = s.charAt(i);
-
-			if (MathEntityType.openGroupSymbols.contains(ch)) {
-				result.append(ch);
-				result.append("</font>");
-				i = processGroup(result, s, i + 1, numberOfOpenings + 1, maxNumberOfGroups);
-				result.append("<font color=\"").append(getColor(maxNumberOfGroups, numberOfOpenings)).append("\">");
-				if (i < s.length() && MathEntityType.closeGroupSymbols.contains(s.charAt(i))) {
-					result.append(s.charAt(i));
-				}
-			} else if (MathEntityType.closeGroupSymbols.contains(ch)) {
-				break;
-			} else {
-				result.append(ch);
-			}
-		}
-
-		result.append("</font>");
-
-
-		return i;
-	}
-
-	private String getColor(int numberOfOpenGroupSymbols, int numberOfOpenings) {
-		final int baseColor = Color.WHITE;
-
-		double c = 1;
-
-		int i = ((int) (255 * c)) * numberOfOpenings / (numberOfOpenGroupSymbols + 1);
-
-		int result = Color.rgb(Color.red(baseColor) - i, Color.green(baseColor) - i, Color.blue(baseColor) - i);
-
-		return "#" + Integer.toHexString(result).substring(2);
-	}
-
-	public boolean isHighlightExpressionInBrackets() {
-		return highlightExpressionInBrackets;
-	}
-
-	public void setHighlightExpressionInBrackets(boolean highlightExpressionInBrackets) {
-		this.highlightExpressionInBrackets = highlightExpressionInBrackets;
-		redraw();
-	}
-}

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

@@ -0,0 +1,157 @@
+/*
+ * Copyright (c) 2009-2011. Created by serso aka se.solovyev.
+ * For more information, please, contact se.solovyev@gmail.com
+ */
+
+package org.solovyev.android.calculator;
+
+import android.content.Context;
+import android.graphics.Color;
+import android.text.Html;
+import android.util.AttributeSet;
+import android.util.Log;
+import android.widget.EditText;
+import org.jetbrains.annotations.NotNull;
+import org.solovyev.android.calculator.math.MathEntityType;
+
+/**
+ * User: serso
+ * Date: 9/17/11
+ * Time: 12:25 AM
+ */
+public class CalculatorEditor extends EditText {
+
+	private boolean highlightText = true;
+
+	public CalculatorEditor(Context context) {
+		super(context);
+	}
+
+	public CalculatorEditor(Context context, AttributeSet attrs) {
+		super(context, attrs);
+	}
+
+	public CalculatorEditor(Context context, AttributeSet attrs, int defStyle) {
+		super(context, attrs, defStyle);
+	}
+
+	public void redraw() {
+		String text = getText().toString();
+
+		int selectionStart = getSelectionStart();
+		int selectionEnd = getSelectionEnd();
+
+		if (highlightText) {
+
+			text = highlightText(text);
+
+			super.setText(Html.fromHtml(text), BufferType.EDITABLE);
+		} else {
+			super.setText(text, BufferType.EDITABLE);
+		}
+
+		setSelection(selectionStart, selectionEnd);
+	}
+
+	private String highlightText(@NotNull final String text) {
+		final String result;
+
+		int maxNumberOfOpenGroupSymbols = 0;
+		int numberOfOpenGroupSymbols = 0;
+
+		final StringBuilder text1 = new StringBuilder();
+
+		for (int i = 0; i < text.length(); i++) {
+			final MathEntityType.Result mathType = MathEntityType.getType(text, i);
+
+			switch (mathType.getMathEntityType()) {
+				case open_group_symbol:
+					numberOfOpenGroupSymbols++;
+					maxNumberOfOpenGroupSymbols = Math.max(maxNumberOfOpenGroupSymbols, numberOfOpenGroupSymbols);
+					text1.append(text.charAt(i));
+					break;
+				case close_group_symbol:
+					numberOfOpenGroupSymbols--;
+					text1.append(text.charAt(i));
+					break;
+				case function:
+					i = processHighlightedText(text1, i, mathType.getS(), "i");
+					break;
+				case constant:
+					i = processHighlightedText(text1, i, mathType.getS(), "b");
+					break;
+				default:
+					text1.append(text.charAt(i));
+			}
+		}
+
+		if (maxNumberOfOpenGroupSymbols > 0) {
+
+			final StringBuilder text2 = new StringBuilder();
+
+			processBracketGroup(text2, text1.toString(), 0, 0, maxNumberOfOpenGroupSymbols);
+
+			Log.d(CalculatorEditor.class.getName(), text2.toString());
+
+			result = text2.toString();
+		} else {
+			result = text1.toString();
+		}
+
+		return result;
+	}
+
+	private int processHighlightedText(@NotNull StringBuilder result, int i, @NotNull String functionName, @NotNull String tag) {
+		result.append("<").append(tag).append(">").append(functionName).append("</").append(tag).append(">");
+		return i + functionName.length() - 1;
+	}
+
+	private int processBracketGroup(@NotNull StringBuilder result, @NotNull String s, int i, int numberOfOpenings, int maxNumberOfGroups) {
+
+		result.append("<font color=\"").append(getColor(maxNumberOfGroups, numberOfOpenings)).append("\">");
+
+		for (; i < s.length(); i++) {
+			char ch = s.charAt(i);
+
+			if (MathEntityType.openGroupSymbols.contains(ch)) {
+				result.append(ch);
+				result.append("</font>");
+				i = processBracketGroup(result, s, i + 1, numberOfOpenings + 1, maxNumberOfGroups);
+				result.append("<font color=\"").append(getColor(maxNumberOfGroups, numberOfOpenings)).append("\">");
+				if (i < s.length() && MathEntityType.closeGroupSymbols.contains(s.charAt(i))) {
+					result.append(s.charAt(i));
+				}
+			} else if (MathEntityType.closeGroupSymbols.contains(ch)) {
+				break;
+			} else {
+				result.append(ch);
+			}
+		}
+
+		result.append("</font>");
+
+
+		return i;
+	}
+
+	private String getColor(int numberOfOpenGroupSymbols, int numberOfOpenings) {
+		final int baseColor = Color.WHITE;
+
+		double c = 1;
+
+		int i = ((int) (255 * c)) * numberOfOpenings / (numberOfOpenGroupSymbols + 1);
+
+		int result = Color.rgb(Color.red(baseColor) - i, Color.green(baseColor) - i, Color.blue(baseColor) - i);
+
+		return "#" + Integer.toHexString(result).substring(2);
+	}
+
+	public boolean isHighlightText() {
+		return highlightText;
+	}
+
+	public void setHighlightText(boolean highlightText) {
+		this.highlightText = highlightText;
+		redraw();
+	}
+}

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

@@ -41,7 +41,7 @@ public class CalculatorModel {
 
 	private static CalculatorModel instance;
 
-	private CalculatorModel(@Nullable Context context) {
+	public CalculatorModel(@Nullable Context context) {
 		load(context);
 
 		reset();

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

@@ -16,6 +16,7 @@ import android.view.*;
 import android.widget.*;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.solovyev.android.calculator.math.MathEntityType;
 import org.solovyev.common.utils.StringUtils;
 
 import java.util.ArrayList;
@@ -150,7 +151,9 @@ public class CalculatorVarsActivity extends ListActivity {
 				if (!StringUtils.isEmpty(name)) {
 					final Var varFromRegister = varsRegister.getVar(name);
 					if (varFromRegister == null || varFromRegister == editedInstance) {
+						final MathEntityType.Result mathType = MathEntityType.getType(name, 0);
 
+						if (mathType.getMathEntityType() == MathEntityType.text || mathType.getMathEntityType() == MathEntityType.constant) {
 							boolean correctDouble = true;
 							try {
 								Double.valueOf(value);
@@ -166,6 +169,9 @@ public class CalculatorVarsActivity extends ListActivity {
 							} else {
 								error = "Value is not a number!";
 							}
+						} else {
+							error = "Variable name clashes with function name!";
+						}
 					} else {
 						error = "Variable with same name already exist!";
 					}

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

@@ -39,7 +39,7 @@ public class CalculatorView implements CursorControl, HistoryControl<CalculatorH
 	public static final int EVAL_DELAY_MILLIS = 500;
 
 	@NotNull
-	private final CalculatorEditText editor;
+	private final CalculatorEditor editor;
 
 	@NotNull
 	private final CalculatorDisplay display;
@@ -59,7 +59,7 @@ public class CalculatorView implements CursorControl, HistoryControl<CalculatorH
 
 		final InputMethodManager imm = (InputMethodManager) activity.getSystemService(Context.INPUT_METHOD_SERVICE);
 
-		this.editor = (CalculatorEditText) activity.findViewById(R.id.editText);
+		this.editor = (CalculatorEditor) activity.findViewById(R.id.editText);
 		this.editor.setInputType(InputType.TYPE_NULL);
 		imm.hideSoftInputFromWindow(this.editor.getWindowToken(), 0);
 
@@ -192,12 +192,11 @@ public class CalculatorView implements CursorControl, HistoryControl<CalculatorH
 				@Override
 				public void doOperation(@NotNull EditText editor) {
 
-					final MathEntityType type = MathEntityType.getType(text, 0);
+					final MathEntityType.Result mathType = MathEntityType.getType(text, 0);
 
 					int cursorPositionOffset = 0;
 					final StringBuilder textToBeInserted = new StringBuilder(text);
-					if (type != null) {
+					switch (mathType.getMathEntityType()) {
-						switch (type) {
 						case function:
 							textToBeInserted.append("()");
 							cursorPositionOffset = -1;
@@ -205,11 +204,6 @@ public class CalculatorView implements CursorControl, HistoryControl<CalculatorH
 						case group_symbols:
 							cursorPositionOffset = -1;
 							break;
-
-							default:
-								break;
-						}
-
 					}
 
 					editor.getText().insert(editor.getSelectionStart(), textToBeInserted.toString());
@@ -287,7 +281,7 @@ public class CalculatorView implements CursorControl, HistoryControl<CalculatorH
 	}
 
 	@NotNull
-	public CalculatorEditText getEditor() {
+	public CalculatorEditor getEditor() {
 		return editor;
 	}
 }

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

@@ -23,35 +23,28 @@ public class ToJsclPreprocessor implements Preprocessor {
 		final StartsWithFinder startsWithFinder = new StartsWithFinder(s, 0);
 		final StringBuilder sb = new StringBuilder();
 
-		boolean constantBefore = false;
+		MathEntityType.Result mathTypeResult = null;
 		for (int i = 0; i < s.length(); i++) {
 			char ch = s.charAt(i);
 			startsWithFinder.setI(i);
 
-			checkMultiplicationSignBeforeFunction(sb, s, i, constantBefore);
+			mathTypeResult = checkMultiplicationSignBeforeFunction(sb, s, i, mathTypeResult);
-			constantBefore = false;
 
-			if (MathEntityType.openGroupSymbols.contains(ch)) {
+			final MathEntityType mathType = mathTypeResult.getMathEntityType();
+			if (mathType == MathEntityType.open_group_symbol) {
 				sb.append('(');
-			} else if (MathEntityType.closeGroupSymbols.contains(ch)) {
+			} else if (mathType == MathEntityType.close_group_symbol) {
 				sb.append(')');
 			} else if (ch == '×' || ch == '∙') {
 				sb.append("*");
+			} else if ( mathType == MathEntityType.function  ){
+				sb.append(toJsclFunction(mathTypeResult.getS()));
+				i += mathTypeResult.getS().length() - 1;
+			} else if ( mathType == MathEntityType.constant ) {
+				sb.append(mathTypeResult.getS());
+				i += mathTypeResult.getS().length() - 1;
 			} else {
-				String entity = CollectionsUtils.get(MathEntityType.prefixFunctions, startsWithFinder);
-				if (entity == null) {
-					entity = CollectionsUtils.get(CalculatorModel.getInstance().getVarsRegister().getVarNames(), startsWithFinder);
-					if (entity == null) {
 				sb.append(ch);
-					} else {
-						sb.append(entity);
-						i += entity.length() - 1;
-						constantBefore = true;
-					}
-				} else {
-					sb.append(toJsclFunction(entity));
-					i += entity.length() - 1;
-				}
 			}
 		}
 
@@ -110,21 +103,17 @@ public class ToJsclPreprocessor implements Preprocessor {
 		int result = position;
 		for (; result >= 0; result--) {
 
-			final MathEntityType mathEntityType = MathEntityType.getType(s, result);
+			final MathEntityType mathEntityType = MathEntityType.getMathEntityType(s, result);
 
-			if (mathEntityType != null) {
 			if (CollectionsUtils.contains(mathEntityType, MathEntityType.digit, MathEntityType.dot)) {
 				// continue
-				} else if (MathEntityType.closeGroupSymbols.contains(s.charAt(result))) {
+			} else if (mathEntityType == MathEntityType.close_group_symbol) {
 				numberOfOpenGroups++;
-				} else if (MathEntityType.openGroupSymbols.contains(s.charAt(result))) {
+			} else if (mathEntityType == MathEntityType.open_group_symbol) {
 				numberOfOpenGroups--;
 			} else {
 				if (stop(s, numberOfOpenGroups, result)) break;
 			}
-			} else {
-				if (stop(s, numberOfOpenGroups, result)) break;
-			}
 		}
 
 		return result;
@@ -136,8 +125,8 @@ public class ToJsclPreprocessor implements Preprocessor {
 				final EndsWithFinder endsWithFinder = new EndsWithFinder(s);
 				endsWithFinder.setI(i + 1);
 				if (!CollectionsUtils.contains(MathEntityType.prefixFunctions, FilterType.included, endsWithFinder)) {
-					MathEntityType type = MathEntityType.getType(s, i);
+					MathEntityType type = MathEntityType.getMathEntityType(s, i);
-					if (type != null && type != MathEntityType.constant) {
+					if (type != MathEntityType.constant) {
 						return true;
 					}
 				}
@@ -185,25 +174,29 @@ public class ToJsclPreprocessor implements Preprocessor {
 		}
 	}
 
-	private static void checkMultiplicationSignBeforeFunction(@NotNull StringBuilder sb, @NotNull String s, int i, boolean constantBefore) {
+	@NotNull
+	private static MathEntityType.Result checkMultiplicationSignBeforeFunction(@NotNull StringBuilder sb,
+																		@NotNull String s,
+																		int i,
+																		@Nullable MathEntityType.Result mathTypeBeforeResult) {
+		MathEntityType.Result result = MathEntityType.getType(s, i);
+
 		if (i > 0) {
-			// get character before function
-			char chBefore = s.charAt(i - 1);
-			char ch = s.charAt(i);
 
-			final MathEntityType mathTypeBefore = MathEntityType.getType(String.valueOf(chBefore));
+			final MathEntityType mathType = result.getMathEntityType();
-			final MathEntityType mathType = MathEntityType.getType(s, i);
+			assert mathTypeBeforeResult != null;
+			final MathEntityType mathTypeBefore = mathTypeBeforeResult.getMathEntityType();
 
-			if (constantBefore || (mathTypeBefore != MathEntityType.binary_operation &&
+			if (mathTypeBefore == MathEntityType.constant || (mathTypeBefore != MathEntityType.binary_operation &&
 					mathTypeBefore != MathEntityType.unary_operation &&
 					mathTypeBefore != MathEntityType.function &&
-					!MathEntityType.openGroupSymbols.contains(chBefore))) {
+					mathTypeBefore != MathEntityType.open_group_symbol)) {
 
 				if (mathType == MathEntityType.constant) {
 					sb.append("*");
-				} else if (MathEntityType.openGroupSymbols.contains(ch) && mathTypeBefore != null) {
+				} else if (mathType == MathEntityType.open_group_symbol && mathTypeBefore != null) {
 					sb.append("*");
-				} else if (mathType == MathEntityType.digit && ((mathTypeBefore != MathEntityType.digit && mathTypeBefore != MathEntityType.dot) || constantBefore) ) {
+				} else if (mathType == MathEntityType.digit && ((mathTypeBefore != MathEntityType.digit && mathTypeBefore != MathEntityType.dot) || mathTypeBefore == MathEntityType.constant)) {
 					sb.append("*");
 				} else {
 					for (String function : MathEntityType.prefixFunctions) {
@@ -215,6 +208,8 @@ public class ToJsclPreprocessor implements Preprocessor {
 				}
 			}
 		}
+
+		return result;
 	}
 
 	public static String wrap(@NotNull JsclOperation operation, @NotNull String s) {

src/main/java/org/solovyev/android/calculator/math/MathEntityType.java

@@ -6,19 +6,16 @@
 package org.solovyev.android.calculator.math;
 
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 import org.solovyev.android.calculator.CalculatorModel;
 import org.solovyev.android.calculator.CharacterAtPositionFinder;
 import org.solovyev.android.calculator.StartsWithFinder;
-import org.solovyev.android.calculator.Var;
-import org.solovyev.common.utils.CollectionsUtils;
 import org.solovyev.common.utils.Finder;
 
-import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 
+import static org.solovyev.common.utils.CollectionsUtils.get;
+
 public enum MathEntityType {
 
 	digit,
@@ -29,11 +26,14 @@ public enum MathEntityType {
 	unary_operation,
 	binary_operation,
 	group_symbols,
-	group_symbol;
+	open_group_symbol,
+	close_group_symbol,
+	text;
 
 	public static final List<String> constants = Arrays.asList("e", "π", "i");
 
 	public static final List<String> digits = Arrays.asList("0", "1", "2", "3", "4", "5", "6", "7", "8", "9");
+
 	public static final List<Character> dots = Arrays.asList('.');
 
 	public static final List<Character> unaryOperations = Arrays.asList('-', '=', '!');
@@ -50,113 +50,114 @@ public enum MathEntityType {
 
 	public static final List<Character> closeGroupSymbols = Arrays.asList(']', ')', '}');
 
-	public static final List<Character> singleGroupSymbols;
+	/**
-
+	 * Method determines mathematical entity type for text substring starting from ith index
-	static {
+	 *
-		final List<Character> list = new ArrayList<Character>();
+	 * @param text analyzed text
-		list.addAll(openGroupSymbols);
+	 * @param i	index which points to start of substring
-		list.addAll(closeGroupSymbols);
+	 * @return math entity type of substring starting from ith index of specified text
-		singleGroupSymbols = Collections.unmodifiableList(list);
+	 */
+	@NotNull
+	public static MathEntityType getMathEntityType(@NotNull String text, int i) {
+		return getType(text, i).getMathEntityType();
 	}
 
-	@Nullable
+	@NotNull
-	public static MathEntityType getType(@NotNull String s) {
+	public static Result getType(@NotNull String text, int i) {
-		MathEntityType result = null;
+		if (i < 0) {
-
+			throw new IllegalArgumentException("I must be more or equals to 0.");
-		if (s.length() == 1) {
+		} else if (i >= text.length() && i != 0) {
-			result = getType(s.charAt(0));
+			throw new IllegalArgumentException("I must be less than size of text.");
+		} else if (i == 0 && text.length() == 0) {
+			return new Result(MathEntityType.text, text);
 		}
 
-		if (result == null) {
+		final StartsWithFinder stringStartWithFinder = new StartsWithFinder(text, i);
-			if (prefixFunctions.contains(s)) {
+		final CharacterAtPositionFinder characterStartWithFinder = new CharacterAtPositionFinder(text, i);
-				result = MathEntityType.function;
+
-			} else if (isConstant(s)) {
+		String foundString = get(digits, stringStartWithFinder);
-				result = MathEntityType.constant;
+		if (foundString != null) {
-			} else if (groupSymbols.contains(s)) {
+			return new Result(MathEntityType.digit, foundString);
-				result = MathEntityType.group_symbols;
-			}
 		}
 
-
+		Character foundCharacter = get(dots, characterStartWithFinder);
-		return result;
+		if (foundCharacter != null) {
+			return new Result(dot, String.valueOf(foundCharacter));
 		}
 
-	@Nullable
+		foundCharacter = get(postfixFunctions, characterStartWithFinder);
-	public static MathEntityType getType(final char ch) {
+		if (foundCharacter != null) {
-		MathEntityType result = null;
+			return new Result(postfix_function, String.valueOf(foundCharacter));
-
-		if (Character.isDigit(ch)) {
-			result = MathEntityType.digit;
-		} else if (postfixFunctions.contains(ch)) {
-			result = MathEntityType.postfix_function;
-		} else if (unaryOperations.contains(ch)) {
-			result = MathEntityType.unary_operation;
-		} else if (binaryOperations.contains(ch)) {
-			result = MathEntityType.binary_operation;
-		} else if (singleGroupSymbols.contains(ch)) {
-			result = MathEntityType.group_symbol;
-		} else if (isConstant(ch)) {
-			result = MathEntityType.constant;
-		} else if (dots.contains(ch)) {
-			result = MathEntityType.dot;
-		}
-		return result;
 		}
 
-	private static boolean isConstant(final char ch) {
+		foundCharacter = get(unaryOperations, characterStartWithFinder);
-		final String name = String.valueOf(ch);
+		if (foundCharacter != null) {
-
+			return new Result(unary_operation, String.valueOf(foundCharacter));
-		return isConstant(name);
 		}
 
-	private static boolean isConstant(final String name) {
+		foundCharacter = get(binaryOperations, characterStartWithFinder);
-		return CollectionsUtils.get(CalculatorModel.getInstance().getVarsRegister().getVars(), new Finder<Var>() {
+		if (foundCharacter != null) {
-			@Override
+			return new Result(binary_operation, String.valueOf(foundCharacter));
-			public boolean isFound(@Nullable Var var) {
-				return var != null && var.getName().equals(name);
-			}
-		}) != null;
 		}
 
-	public static MathEntityType getType(String s, int i) {
+		foundString = get(groupSymbols, stringStartWithFinder);
-		final StartsWithFinder startsWithFinder = new StartsWithFinder(s, i);
+		if (foundString != null) {
-		final CharacterAtPositionFinder characterStartWithFinder = new CharacterAtPositionFinder(s, i);
+			return new Result(MathEntityType.group_symbols, foundString);
-
-		return getType(startsWithFinder, characterStartWithFinder);
 		}
 
-	@Nullable
+		foundCharacter = get(openGroupSymbols, characterStartWithFinder);
-	private static MathEntityType getType(@NotNull Finder<String> finder, @NotNull CharacterAtPositionFinder characterStartWithFinder) {
+		if (foundCharacter != null) {
-		MathEntityType result = null;
+			return new Result(open_group_symbol, String.valueOf(foundCharacter));
-
-		if (contains(digits, finder)) {
-			result = MathEntityType.digit;
-		} else if (contains(postfixFunctions, characterStartWithFinder)) {
-			result = MathEntityType.postfix_function;
-		} else if (contains(unaryOperations, characterStartWithFinder)) {
-			result = MathEntityType.unary_operation;
-		} else if (contains(binaryOperations, characterStartWithFinder)) {
-			result = MathEntityType.binary_operation;
-		} else if (contains(groupSymbols, finder)) {
-			result = MathEntityType.group_symbols;
-		} else if (contains(singleGroupSymbols, characterStartWithFinder)) {
-			result = MathEntityType.group_symbol;
-		} else if (contains(prefixFunctions, finder)) {
-			result = MathEntityType.function;
-		} else if (contains(CalculatorModel.getInstance().getVarsRegister().getVarNames(), finder)) {
-			result = MathEntityType.constant;
-		} else if (contains(dots, characterStartWithFinder)) {
-			result = MathEntityType.dot;
 		}
 
-		return result;
+		foundCharacter = get(closeGroupSymbols, characterStartWithFinder);
+		if (foundCharacter != null) {
+			return new Result(close_group_symbol, String.valueOf(foundCharacter));
+		}
+
+		foundString = get(prefixFunctions, stringStartWithFinder);
+		if (foundString != null) {
+			return new Result(MathEntityType.function, foundString);
+		}
+
+		foundString = get(CalculatorModel.getInstance().getVarsRegister().getVarNames(), stringStartWithFinder);
+		if (foundString != null) {
+			return new Result(MathEntityType.constant, foundString);
+		}
+
+		return new Result(MathEntityType.text, text.substring(i));
+	}
+
+	public static class Result {
+
+		@NotNull
+		private final MathEntityType mathEntityType;
+
+		@NotNull
+		private final String s;
+
+		private Result(@NotNull MathEntityType mathEntityType, @NotNull String s){
+			this.mathEntityType = mathEntityType;
+
+			this.s = s;
+		}
+
+		@NotNull
+		public String getS() {
+			return s;
+		}
+
+		@NotNull
+		public MathEntityType getMathEntityType() {
+			return mathEntityType;
+		}
 	}
 
 	private static boolean contains(@NotNull List<String> list, @NotNull final Finder<String> startsWithFinder) {
-		return CollectionsUtils.get(list, startsWithFinder) != null;
+		return get(list, startsWithFinder) != null;
 	}
 
 	private static boolean contains(@NotNull List<Character> list, @NotNull final CharacterAtPositionFinder atPositionFinder) {
-		return CollectionsUtils.get(list, atPositionFinder) != null;
+		return get(list, atPositionFinder) != null;
 	}
 }

src/test/java/org/solovyev/android/calculator/math/MathEntityTypeTest.java

@@ -0,0 +1,45 @@
+/*
+ * 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.math;
+
+import junit.framework.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.solovyev.android.calculator.CalculatorModel;
+
+/**
+ * User: serso
+ * Date: 10/5/11
+ * Time: 1:25 AM
+ */
+public class MathEntityTypeTest {
+
+	@BeforeClass
+	public static void setUp() throws Exception {
+		CalculatorModel.init(null);
+	}
+
+	@Test
+	public void testGetType() throws Exception {
+		Assert.assertEquals(MathEntityType.function, MathEntityType.getType("sin", 0).getMathEntityType());
+		Assert.assertEquals(MathEntityType.text, MathEntityType.getType("sn", 0).getMathEntityType());
+		Assert.assertEquals(MathEntityType.text, MathEntityType.getType("s", 0).getMathEntityType());
+		Assert.assertEquals(MathEntityType.text, MathEntityType.getType("", 0).getMathEntityType());
+
+		try {
+			Assert.assertEquals(MathEntityType.text, MathEntityType.getType("22", -1).getMathEntityType());
+			Assert.fail();
+		} catch (IllegalArgumentException e) {
+		}
+
+		try {
+			Assert.assertEquals(MathEntityType.text, MathEntityType.getType("22", 2).getMathEntityType());
+			Assert.fail();
+		} catch (IllegalArgumentException e) {
+		}
+	}
+}