Merged FunctionBase class to Function class.

.settings/org.eclipse.core.resources.prefs

@@ -1,12 +1,12 @@
 eclipse.preferences.version=1
 encoding//src/org/nevec/rjm/BigSurd.java=UTF-8
 encoding//src/org/nevec/rjm/BigSurdVec.java=UTF-8
-encoding//src/org/warp/engine=UTF-8
-encoding//src/org/warp/engine/Display.java=UTF-8
-encoding//src/org/warp/picalculator/Expression.java=UTF-8
 encoding//src/org/warp/picalculator/Main.java=UTF-8
-encoding//src/org/warp/picalculator/MathematicalSymbols.java=UTF-8
+encoding//src/org/warp/picalculator/device/graphicengine=UTF-8
-encoding//src/org/warp/picalculator/Root.java=UTF-8
+encoding//src/org/warp/picalculator/device/graphicengine/Display.java=UTF-8
-encoding//src/org/warp/picalculator/RootSquare.java=UTF-8
+encoding//src/org/warp/picalculator/math/MathematicalSymbols.java=UTF-8
+encoding//src/org/warp/picalculator/math/functions/Expression.java=UTF-8
+encoding//src/org/warp/picalculator/math/functions/Root.java=UTF-8
+encoding//src/org/warp/picalculator/math/functions/RootSquare.java=UTF-8
 encoding//src/org/warp/picalculator/screens/EquationScreen.java=UTF-8
 encoding/<project>=UTF-8

src/org/nevec/rjm/NumeroAvanzato.java

@@ -6,7 +6,7 @@ import java.math.MathContext;
 import java.security.ProviderException;
 
 import org.warp.picalculator.Error;
-import org.warp.picalculator.Variables;
+import org.warp.picalculator.math.Variables;
 
 /**
  * Square roots on the real line. These represent numbers which are a product of

src/org/nevec/rjm/NumeroAvanzatoVec.java

@@ -7,8 +7,8 @@ import java.util.Comparator;
 import java.util.Vector;
 
 import org.warp.picalculator.Error;
-import org.warp.picalculator.Variables;
 import org.warp.picalculator.Utils;
+import org.warp.picalculator.math.Variables;
 
 /**
  * A NumeroAvanzatoVec represents an algebraic sum or differences of values

src/org/warp/picalculator/AnteriorFunctionBase.java

@@ -1,109 +0,0 @@
-package org.warp.picalculator;
-
-import static org.warp.engine.Display.Render.getStringWidth;
-import static org.warp.engine.Display.Render.glDrawStringLeft;
-
-import java.util.List;
-
-import org.nevec.rjm.NumeroAvanzatoVec;
-import org.warp.device.PIDisplay;
-import org.warp.engine.Display;
-
-import com.rits.cloning.Cloner;
-
-public abstract class AnteriorFunctionBase extends FunctionBase {
-	public AnteriorFunctionBase(FunctionBase value) {
-		setVariable(value);
-	}
-
-	protected FunctionBase variable = new Number(NumeroAvanzatoVec.ZERO);
-	protected int width;
-	protected int height;
-	protected int line;
-	protected boolean small;
-	
-	public FunctionBase getVariable() {
-		return variable;
-	}
-
-	public void setVariable(FunctionBase value) {
-		variable = value;
-	}
-
-	@Override
-	public abstract String getSymbol();
-
-	@Override
-	public abstract List<Function> solveOneStep() throws Error;
-
-	protected int stepsCount = -1;
-	@Override
-	public int getStepsCount() {
-		if (stepsCount == -1) {
-			stepsCount = variable.getStepsCount()+1;
-		}
-		return stepsCount;
-	}
-	
-	@Override
-	public void generateGraphics() {
-		variable.setSmall(small);
-		variable.generateGraphics();
-		
-		width = getStringWidth(getSymbol()) + 1 + getVariable().getWidth();
-		height = variable.getHeight();
-		line = variable.getLine();
-	}
-
-	@Override
-	public void draw(int x, int y) {
-		float h1 = getVariable().getHeight();
-		int wsegno = getStringWidth(getSymbol());
-		float hsegno = Utils.getFontHeight(small);
-		float maxh = getHeight();
-		if (small) {
-			Display.Render.setFont(PIDisplay.fonts[1]);
-		} else {
-			Display.Render.setFont(PIDisplay.fonts[0]);
-		}
-		
-		glDrawStringLeft(x, (int) Math.floor(y + (maxh - hsegno) / 2), getSymbol());
-		getVariable().draw(x + wsegno + 1, (int) Math.floor(y + (maxh - h1) / 2));
-	}
-
-	@Override
-	public int getWidth() {
-		return width;
-	}
-
-	@Override
-	public int getHeight() {
-		return height;
-	}
-
-	@Override
-	public int getLine() {
-		return line;
-	}
-
-	@Override
-	public String toString() {
-//		try {
-//			return solve().toString();
-		return "TODO: fare una nuova alternativa a solve().toString()";
-//		} catch (Error e) {
-//			return e.id.toString();
-//		}
-	}
-
-	@Override
-	public AnteriorFunctionBase clone() {
-		Cloner cloner = new Cloner();
-		return cloner.deepClone(this);
-	}
-	
-	@Override
-	public void setSmall(boolean small) {
-		this.small = small;
-	}	
-}

src/org/warp/picalculator/FunctionBase.java

@@ -1,34 +0,0 @@
-package org.warp.picalculator;
-
-import java.util.List;
-
-public abstract class FunctionBase implements Function {
-
-	@Override
-	public abstract String getSymbol();
-
-	@Override
-	public abstract int getStepsCount();
-	
-	@Override
-	public abstract List<Function> solveOneStep() throws Error;
-
-	@Override
-	public abstract void generateGraphics();
-
-	@Override
-	public abstract void draw(int x, int y);
-
-	@Override	
-	public abstract int getWidth();
-
-	@Override
-	public abstract int getHeight();
-
-	@Override
-	public abstract int getLine();
-
-	@Override
-	public abstract void setSmall(boolean small);
-
-}

src/org/warp/picalculator/FunctionMultipleValuesBase.java

@@ -1,106 +0,0 @@
-package org.warp.picalculator;
-
-import java.util.Arrays;
-import java.util.List;
-
-import com.rits.cloning.Cloner;
-
-public abstract class FunctionMultipleValuesBase extends FunctionBase {
-	public FunctionMultipleValuesBase() {
-		setVariables(new FunctionBase[] {});
-	}
-
-	public FunctionMultipleValuesBase(FunctionBase[] values) {
-		setVariables(values);
-	}
-
-	protected FunctionBase[] variables;
-	protected int width;
-	protected int height;
-	protected int line;
-	protected boolean small;
-
-	public FunctionBase[] getVariables() {
-		return variables;
-	}
-
-	public void setVariables(FunctionBase[] value) {
-		variables = value;
-	}
-
-	public void setVariables(final List<FunctionBase> value) {
-		int vsize = value.size();
-		FunctionBase[] tmp = new FunctionBase[vsize];
-		for (int i = 0; i < vsize; i++) {
-			tmp[i] = value.get(i);
-		}
-		variables = tmp;
-	}
-
-	public FunctionBase getVariable(int index) {
-		return variables[index];
-	}
-
-	public void setVariable(int index, FunctionBase value) {
-		variables[index] = value;
-	}
-
-	public void addVariableToEnd(FunctionBase value) {
-		int index = variables.length;
-		setVariablesLength(index + 1);
-		variables[index] = value;
-	}
-
-	public int getVariablesLength() {
-		return variables.length;
-	}
-
-	public void setVariablesLength(int length) {
-		variables = Arrays.copyOf(variables, length);
-	}
-	
-	protected int stepsCount = -1;
-	@Override
-	public int getStepsCount() {
-		if (stepsCount == -1) {
-			int max = 0;
-			int cur = 0;
-			for (Function f : variables) {
-				cur = f.getStepsCount();
-				if (max < cur) {
-					max = cur;
-				}
-			}
-			return max+1;
-		} else {
-			return stepsCount;
-		}
-	}
-
-	@Override
-	public abstract String getSymbol();
-
-	@Override
-	public abstract void generateGraphics();
-
-	@Override
-	public String toString() {
-//		try {
-//			return solve().toString();
-		return "TODO: fare una nuova alternativa a solve().toString()";
-//		} catch (Error e) {
-//			return e.id.toString();
-//		}
-	}
-
-	@Override
-	public FunctionMultipleValuesBase clone() {
-		Cloner cloner = new Cloner();
-		return cloner.deepClone(this);
-	}
-	
-	@Override
-	public void setSmall(boolean small) {
-		this.small = small;
-	}
-}

src/org/warp/picalculator/FunctionTwoValuesBase.java

@@ -1,160 +0,0 @@
-package org.warp.picalculator;
-
-import static org.warp.engine.Display.Render.getStringWidth;
-import static org.warp.engine.Display.Render.glDrawStringLeft;
-
-import java.util.List;
-
-import org.nevec.rjm.Rational;
-import org.warp.device.PIDisplay;
-import org.warp.engine.Display;
-
-import com.rits.cloning.Cloner;
-
-public abstract class FunctionTwoValuesBase extends FunctionBase {
-	public FunctionTwoValuesBase(FunctionBase value1, FunctionBase value2) {
-		setVariable1(value1);
-		setVariable2(value2);
-	}
-
-	protected FunctionBase variable1 = new Number(Rational.ZERO);
-	protected int width;
-	protected int height;
-	protected int line;
-	protected boolean small;
-
-	public FunctionBase getVariable1() {
-		return variable1;
-	}
-
-	public void setVariable1(FunctionBase value) {
-		variable1 = value;
-	}
-
-	protected FunctionBase variable2 = new Number(Rational.ZERO);
-
-	public FunctionBase getVariable2() {
-		return variable2;
-	}
-
-	public void setVariable2(FunctionBase value) {
-		variable2 = value;
-	}
-
-	@Override
-	public abstract String getSymbol();
-
-	@Override
-	public abstract List<Function> solveOneStep() throws Error;
-	
-	@Override
-	public void generateGraphics() {
-		variable1.setSmall(small);
-		variable1.generateGraphics();
-		
-		variable2.setSmall(small);
-		variable2.generateGraphics();
-		
-		width = calcWidth();
-		height = calcHeight();
-		line = calcLine();
-	}
-
-	@Override
-	public void draw(int x, int y) {
-		int ln = getLine();
-		int dx = 0;
-		variable1.draw(dx + x, ln - variable1.getLine() + y);
-		dx += 1+variable1.getWidth();
-		if (drawSignum()) {
-			if (small) {
-				Display.Render.setFont(PIDisplay.fonts[1]);
-			} else {
-				Display.Render.setFont(PIDisplay.fonts[0]);
-			}
-			glDrawStringLeft(dx + x, ln - Utils.getFontHeight(small) / 2 + y, getSymbol());
-			dx += getStringWidth(getSymbol());
-		}
-		variable2.draw(dx + x, ln - variable2.getLine() + y);
-	}
-
-	@Override
-	public int getWidth() {
-		return width;
-	}
-
-	@Override
-	public int getHeight() {
-		return height;
-	}
-
-	@Override
-	public int getLine() {
-		return line;
-	}
-
-	@Override
-	public String toString() {
-//		try {
-//			return solve().toString();
-			return "TODO: fare una nuova alternativa a solve().toString()";
-//		} catch (Error e) {
-//			return e.id.toString();
-//		}
-	}
-
-	@Override
-	public FunctionTwoValuesBase clone() {
-		Cloner cloner = new Cloner();
-		return cloner.deepClone(this);
-	}
-
-	public boolean drawSignum() {
-		return true;
-	}
-	
-	@Override
-	public void setSmall(boolean small) {
-		this.small = small;
-	}	
-
-	protected int calcWidth() {
-		return variable1.getWidth() + 1 + (drawSignum() ? getStringWidth(getSymbol()) : 0) + variable2.getWidth();
-	}
-	
-	protected int calcHeight() {
-
-		FunctionBase tmin = variable1;
-		FunctionBase tmax = variable1;
-		if (tmin == null || variable2.getLine() >= tmin.getLine()) {
-			tmin = variable2;
-		}
-		if (tmax == null || variable2.getHeight() - variable2.getLine() >= tmax.getHeight() - tmax.getLine()) {
-			tmax = variable2;
-		}
-		return tmin.getLine() + tmax.getHeight() - tmax.getLine();
-	}
-	
-	protected int calcLine() {
-		FunctionBase tl = variable1;
-		if (tl == null || variable2.getLine() >= tl.getLine()) {
-			tl = variable2;
-		}
-		return tl.getLine();
-	}
-	
-	protected int stepsCount = -1;
-	@Override
-	public int getStepsCount() {
-		if (stepsCount == -1) {
-			int val1 = variable1.getStepsCount();
-			int val2 = variable2.getStepsCount();
-			if (val1 > val2) {
-				stepsCount = val1+1;
-			} else {
-				stepsCount = val2+1;
-			}
-		}
-		return stepsCount;
-	}
-}

src/org/warp/picalculator/Main.java

@@ -1,7 +1,7 @@
 package org.warp.picalculator;
 
-import org.warp.device.Keyboard;
+import org.warp.picalculator.device.Keyboard;
-import org.warp.device.PIDisplay;
+import org.warp.picalculator.device.PIDisplay;
 import org.warp.picalculator.screens.EquationScreen;
 
 import com.pi4j.wiringpi.Gpio;

src/org/warp/picalculator/Utils.java

@@ -1,6 +1,6 @@
 package org.warp.picalculator;
 
-import static org.warp.engine.Display.Render.glDrawLine;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glDrawLine;
 
 import java.awt.Font;
 import java.io.ByteArrayOutputStream;
@@ -15,6 +15,20 @@ import java.util.List;
 
 import org.nevec.rjm.BigDecimalMath;
 import org.nevec.rjm.Rational;
+import org.warp.picalculator.math.Variable;
+import org.warp.picalculator.math.functions.AnteriorFunction;
+import org.warp.picalculator.math.functions.Division;
+import org.warp.picalculator.math.functions.Expression;
+import org.warp.picalculator.math.functions.Function;
+import org.warp.picalculator.math.functions.FunctionTwoValues;
+import org.warp.picalculator.math.functions.Multiplication;
+import org.warp.picalculator.math.functions.Number;
+import org.warp.picalculator.math.functions.PrioritaryMultiplication;
+import org.warp.picalculator.math.functions.Subtraction;
+import org.warp.picalculator.math.functions.Sum;
+import org.warp.picalculator.math.functions.SumSubtraction;
+import org.warp.picalculator.math.functions.equations.Equation;
+import org.warp.picalculator.math.functions.equations.EquationsSystemPart;
 
 public class Utils {
 
@@ -84,12 +98,12 @@ public class Utils {
 	public static boolean areThereOnlySettedUpFunctionsSumsEquationsAndSystems(ArrayList<Function> fl) {
 		for (int i = 0; i < fl.size(); i++) {
 			if (!(fl.get(i) instanceof Number || fl.get(i) instanceof Sum || fl.get(i) instanceof SumSubtraction || fl.get(i) instanceof Equation || fl.get(i) instanceof EquationsSystemPart || fl.get(i) instanceof Expression)) {
-				if (fl.get(i) instanceof AnteriorFunctionBase) {
+				if (fl.get(i) instanceof AnteriorFunction) {
-					if (((AnteriorFunctionBase) fl.get(i)).variable == null) {
+					if (((AnteriorFunction) fl.get(i)).getVariable() == null) {
 						return false;
 					}
-				} else if (fl.get(i) instanceof FunctionTwoValuesBase) {
+				} else if (fl.get(i) instanceof FunctionTwoValues) {
-					if (((FunctionTwoValuesBase) fl.get(i)).variable1 == null || ((FunctionTwoValuesBase) fl.get(i)).variable2 == null) {
+					if (((FunctionTwoValues) fl.get(i)).getVariable1() == null || ((FunctionTwoValues) fl.get(i)).getVariable2() == null) {
 						return false;
 					}
 				} else {
@@ -103,12 +117,12 @@ public class Utils {
 	public static boolean areThereOnlySettedUpFunctionsSumsMultiplicationsEquationsAndSystems(ArrayList<Function> fl) {
 		for (int i = 0; i < fl.size(); i++) {
 			if (!(fl.get(i) instanceof Number || fl.get(i) instanceof Multiplication || fl.get(i) instanceof PrioritaryMultiplication || fl.get(i) instanceof Sum || fl.get(i) instanceof SumSubtraction || fl.get(i) instanceof Equation || fl.get(i) instanceof EquationsSystemPart || fl.get(i) instanceof Expression)) {
-				if (fl.get(i) instanceof AnteriorFunctionBase) {
+				if (fl.get(i) instanceof AnteriorFunction) {
-					if (((AnteriorFunctionBase) fl.get(i)).variable == null) {
+					if (((AnteriorFunction) fl.get(i)).getVariable() == null) {
 						return false;
 					}
-				} else if (fl.get(i) instanceof FunctionTwoValuesBase) {
+				} else if (fl.get(i) instanceof FunctionTwoValues) {
-					if (((FunctionTwoValuesBase) fl.get(i)).variable1 == null || ((FunctionTwoValuesBase) fl.get(i)).variable2 == null) {
+					if (((FunctionTwoValues) fl.get(i)).getVariable1() == null || ((FunctionTwoValues) fl.get(i)).getVariable2() == null) {
 						return false;
 					}
 				} else {
@@ -122,12 +136,12 @@ public class Utils {
 	public static boolean areThereOnlySettedUpFunctionsEquationsAndSystems(ArrayList<Function> fl) {
 		for (int i = 0; i < fl.size(); i++) {
 			if (!(fl.get(i) instanceof Number || fl.get(i) instanceof Equation || fl.get(i) instanceof EquationsSystemPart || fl.get(i) instanceof Expression)) {
-				if (fl.get(i) instanceof AnteriorFunctionBase) {
+				if (fl.get(i) instanceof AnteriorFunction) {
-					if (((AnteriorFunctionBase) fl.get(i)).variable == null) {
+					if (((AnteriorFunction) fl.get(i)).getVariable() == null) {
 						return false;
 					}
-				} else if (fl.get(i) instanceof FunctionTwoValuesBase) {
+				} else if (fl.get(i) instanceof FunctionTwoValues) {
-					if (((FunctionTwoValuesBase) fl.get(i)).variable1 == null || ((FunctionTwoValuesBase) fl.get(i)).variable2 == null) {
+					if (((FunctionTwoValues) fl.get(i)).getVariable1() == null || ((FunctionTwoValues) fl.get(i)).getVariable2() == null) {
 						return false;
 					}
 				} else {
@@ -141,12 +155,12 @@ public class Utils {
 	public static boolean areThereOnlySettedUpFunctionsAndSystems(ArrayList<Function> fl) {
 		for (int i = 0; i < fl.size(); i++) {
 			if (!(fl.get(i) instanceof Number || fl.get(i) instanceof Equation || fl.get(i) instanceof EquationsSystemPart || fl.get(i) instanceof Expression)) {
-				if (fl.get(i) instanceof AnteriorFunctionBase) {
+				if (fl.get(i) instanceof AnteriorFunction) {
-					if (((AnteriorFunctionBase) fl.get(i)).variable == null) {
+					if (((AnteriorFunction) fl.get(i)).getVariable() == null) {
 						return false;
 					}
-				} else if (fl.get(i) instanceof FunctionTwoValuesBase) {
+				} else if (fl.get(i) instanceof FunctionTwoValues) {
-					if (((FunctionTwoValuesBase) fl.get(i)).variable1 == null || ((FunctionTwoValuesBase) fl.get(i)).variable2 == null) {
+					if (((FunctionTwoValues) fl.get(i)).getVariable1() == null || ((FunctionTwoValues) fl.get(i)).getVariable2() == null) {
 						return false;
 					}
 				} else {
@@ -157,10 +171,10 @@ public class Utils {
 		return true;
 	}
 
-	public static boolean areThereOnlyEmptySNFunctions(ArrayList<FunctionBase> fl) {
+	public static boolean areThereOnlyEmptySNFunctions(ArrayList<Function> fl) {
 		for (int i = 0; i < fl.size(); i++) {
-			if (fl.get(i) instanceof AnteriorFunctionBase) {
+			if (fl.get(i) instanceof AnteriorFunction) {
-				if (((AnteriorFunctionBase) fl.get(i)).variable == null) {
+				if (((AnteriorFunction) fl.get(i)).getVariable() == null) {
 					return true;
 				}
 			}
@@ -168,10 +182,10 @@ public class Utils {
 		return false;
 	}
 
-	public static boolean areThereOnlyEmptyNSNFunctions(ArrayList<FunctionBase> fl) {
+	public static boolean areThereOnlyEmptyNSNFunctions(ArrayList<Function> fl) {
 		for (int i = 0; i < fl.size(); i++) {
-			if (fl.get(i) instanceof FunctionTwoValuesBase && !(fl.get(i) instanceof Sum) && !(fl.get(i) instanceof SumSubtraction) && !(fl.get(i) instanceof Subtraction) && !(fl.get(i) instanceof Multiplication) && !(fl.get(i) instanceof PrioritaryMultiplication) && !(fl.get(i) instanceof Division)) {
+			if (fl.get(i) instanceof FunctionTwoValues && !(fl.get(i) instanceof Sum) && !(fl.get(i) instanceof SumSubtraction) && !(fl.get(i) instanceof Subtraction) && !(fl.get(i) instanceof Multiplication) && !(fl.get(i) instanceof PrioritaryMultiplication) && !(fl.get(i) instanceof Division)) {
-				if (((FunctionTwoValuesBase) fl.get(i)).variable1 == null && ((FunctionTwoValuesBase) fl.get(i)).variable2 == null) {
+				if (((FunctionTwoValues) fl.get(i)).getVariable1() == null && ((FunctionTwoValues) fl.get(i)).getVariable2() == null) {
 					return true;
 				}
 			}
@@ -180,10 +194,10 @@ public class Utils {
 	}
 
 
-	public static boolean areThereEmptyPrioritaryMultiplications(ArrayList<FunctionBase> funzioniOLD) {
+	public static boolean areThereEmptyPrioritaryMultiplications(ArrayList<Function> funzioniOLD) {
 		for (int i = 0; i < funzioniOLD.size(); i++) {
 			if (funzioniOLD.get(i) instanceof PrioritaryMultiplication) {
-				if (((FunctionTwoValuesBase) funzioniOLD.get(i)).variable1 == null && ((FunctionTwoValuesBase) funzioniOLD.get(i)).variable2 == null) {
+				if (((FunctionTwoValues) funzioniOLD.get(i)).getVariable1() == null && ((FunctionTwoValues) funzioniOLD.get(i)).getVariable2() == null) {
 					return true;
 				}
 			}
@@ -191,10 +205,10 @@ public class Utils {
 		return false;
 	}
 	
-	public static boolean areThereEmptyMultiplications(ArrayList<FunctionBase> fl) {
+	public static boolean areThereEmptyMultiplications(ArrayList<Function> fl) {
 		for (int i = 0; i < fl.size(); i++) {
 			if (fl.get(i) instanceof Multiplication || fl.get(i) instanceof Division) {
-				if (((FunctionTwoValuesBase) fl.get(i)).variable1 == null && ((FunctionTwoValuesBase) fl.get(i)).variable2 == null) {
+				if (((FunctionTwoValues) fl.get(i)).getVariable1() == null && ((FunctionTwoValues) fl.get(i)).getVariable2() == null) {
 					return true;
 				}
 			}
@@ -202,10 +216,10 @@ public class Utils {
 		return false;
 	}
 
-	public static boolean areThereEmptySums(ArrayList<FunctionBase> fl) {
+	public static boolean areThereEmptySums(ArrayList<Function> fl) {
 		for (int i = 0; i < fl.size(); i++) {
 			if (fl.get(i) instanceof Sum || fl.get(i) instanceof SumSubtraction) {
-				if (((FunctionTwoValuesBase) fl.get(i)).variable1 == null && ((FunctionTwoValuesBase) fl.get(i)).variable2 == null) {
+				if (((FunctionTwoValues) fl.get(i)).getVariable1() == null && ((FunctionTwoValues) fl.get(i)).getVariable2() == null) {
 					return true;
 				}
 			}
@@ -216,7 +230,7 @@ public class Utils {
 	public static boolean areThereEmptySystems(ArrayList<Function> fl) {
 		for (int i = 0; i < fl.size(); i++) {
 			if (fl.get(i) instanceof EquationsSystemPart) {
-				if (((EquationsSystemPart) fl.get(i)).variable == null) {
+				if (((EquationsSystemPart) fl.get(i)).getVariable() == null) {
 					return true;
 				}
 			}
@@ -226,13 +240,13 @@ public class Utils {
 
 	public static boolean areThereOtherSettedUpFunctions(ArrayList<Function> fl) {
 		for (int i = 0; i < fl.size(); i++) {
-			if (!(fl.get(i) instanceof Number || fl.get(i) instanceof Sum ||  fl.get(i) instanceof SumSubtraction || fl.get(i) instanceof Expression || fl.get(i) instanceof AnteriorFunctionBase || fl.get(i) instanceof Multiplication || fl.get(i) instanceof PrioritaryMultiplication || fl.get(i) instanceof Division)) {
+			if (!(fl.get(i) instanceof Number || fl.get(i) instanceof Sum ||  fl.get(i) instanceof SumSubtraction || fl.get(i) instanceof Expression || fl.get(i) instanceof AnteriorFunction || fl.get(i) instanceof Multiplication || fl.get(i) instanceof PrioritaryMultiplication || fl.get(i) instanceof Division)) {
-				if (fl.get(i) instanceof AnteriorFunctionBase) {
+				if (fl.get(i) instanceof AnteriorFunction) {
-					if (((AnteriorFunctionBase) fl.get(i)).variable == null) {
+					if (((AnteriorFunction) fl.get(i)).getVariable() == null) {
 						return true;
 					}
-				} else if (fl.get(i) instanceof FunctionTwoValuesBase) {
+				} else if (fl.get(i) instanceof FunctionTwoValues) {
-					if (((FunctionTwoValuesBase) fl.get(i)).variable1 == null || ((FunctionTwoValuesBase) fl.get(i)).variable2 == null) {
+					if (((FunctionTwoValues) fl.get(i)).getVariable1() == null || ((FunctionTwoValues) fl.get(i)).getVariable2() == null) {
 						return true;
 					}
 				} else {

src/org/warp/picalculator/device/Keyboard.java

@@ -1,12 +1,12 @@
-package org.warp.device;
+package org.warp.picalculator.device;
 
-import org.warp.engine.Display;
-import org.warp.engine.Screen;
-import org.warp.picalculator.Calculator;
 import org.warp.picalculator.Main;
 import org.warp.picalculator.Utils;
 import org.warp.picalculator.device.chip.ParallelToSerial;
 import org.warp.picalculator.device.chip.SerialToParallel;
+import org.warp.picalculator.device.graphicengine.Display;
+import org.warp.picalculator.device.graphicengine.Screen;
+import org.warp.picalculator.math.Calculator;
 import org.warp.picalculator.screens.MarioScreen;
 
 import com.pi4j.wiringpi.Gpio;

src/org/warp/picalculator/device/PIDisplay.java

@@ -1,19 +1,19 @@
-package org.warp.device;
+package org.warp.picalculator.device;
 
-import static org.warp.engine.Display.Render.*;
+import static org.warp.picalculator.device.graphicengine.Display.Render.*;
 
 import java.awt.image.BufferedImage;
 import java.io.IOException;
 
 import javax.imageio.ImageIO;
 
-import org.warp.engine.Display;
-import org.warp.engine.Display.Startable;
-import org.warp.engine.RAWFont;
-import org.warp.engine.Screen;
-import org.warp.picalculator.Calculator;
 import org.warp.picalculator.Main;
 import org.warp.picalculator.Utils;
+import org.warp.picalculator.device.graphicengine.Display;
+import org.warp.picalculator.device.graphicengine.RAWFont;
+import org.warp.picalculator.device.graphicengine.Screen;
+import org.warp.picalculator.device.graphicengine.Display.Startable;
+import org.warp.picalculator.math.Calculator;
 
 import com.pi4j.wiringpi.Gpio;
 

src/org/warp/picalculator/device/PIFrame.java

@@ -1,4 +1,4 @@
-package org.warp.device;
+package org.warp.picalculator.device;
 
 import java.awt.Cursor;
 import java.awt.Frame;
@@ -14,8 +14,8 @@ import java.awt.image.BufferedImage;
 import javax.swing.JFrame;
 import javax.swing.JPanel;
 
-import org.warp.device.Keyboard.Key;
+import org.warp.picalculator.device.Keyboard.Key;
-import org.warp.engine.Display;
+import org.warp.picalculator.device.graphicengine.Display;
 
 public class PIFrame extends JFrame {
 	private static final long serialVersionUID = 2945898937634075491L;

src/org/warp/picalculator/device/graphicengine/Display.java

@@ -1,13 +1,13 @@
-package org.warp.engine;
+package org.warp.picalculator.device.graphicengine;
 
 import java.awt.FontMetrics;
 import java.awt.Graphics;
 import java.awt.image.BufferedImage;
 import java.awt.image.DataBufferInt;
 
-import org.warp.device.PIDisplay;
-import org.warp.device.PIFrame;
 import org.warp.picalculator.Main;
+import org.warp.picalculator.device.PIDisplay;
+import org.warp.picalculator.device.PIFrame;
 
 public class Display {
 

src/org/warp/picalculator/device/graphicengine/RAWFont.java

@@ -1,4 +1,4 @@
-package org.warp.engine;
+package org.warp.picalculator.device.graphicengine;
 
 import java.awt.image.BufferedImage;
 import java.awt.image.DataBufferInt;

src/org/warp/picalculator/device/graphicengine/Screen.java

@@ -1,7 +1,7 @@
-package org.warp.engine;
+package org.warp.picalculator.device.graphicengine;
 
-import org.warp.device.Keyboard.Key;
+import org.warp.picalculator.device.PIDisplay;
-import org.warp.device.PIDisplay;
+import org.warp.picalculator.device.Keyboard.Key;
 
 public abstract class Screen {
 	public PIDisplay d;

src/org/warp/picalculator/math/Calculator.java

@@ -1,12 +1,22 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math;
 
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.LinkedHashSet;
 import java.util.List;
+import java.util.Set;
 
 import org.nevec.rjm.NumeroAvanzato;
-import org.warp.device.PIDisplay;
+import org.warp.picalculator.Error;
-import org.warp.engine.Screen;
+import org.warp.picalculator.Errors;
+import org.warp.picalculator.Utils;
+import org.warp.picalculator.device.PIDisplay;
+import org.warp.picalculator.device.graphicengine.Screen;
+import org.warp.picalculator.math.functions.Expression;
+import org.warp.picalculator.math.functions.Function;
+import org.warp.picalculator.math.functions.Number;
+import org.warp.picalculator.math.functions.equations.Equation;
+import org.warp.picalculator.math.functions.equations.EquationsSystem;
 import org.warp.picalculator.screens.EquationScreen;
 import org.warp.picalculator.screens.SolveEquationScreen;
 
@@ -58,8 +68,9 @@ public class Calculator {
 				results.add(es.f);
 				while (Utils.allSolved(results) == false) {
 					for (Function itm : results) {
-						if (itm.getStepsCount() > 0) {
+						if (itm.getStepsCount() != 0) {
-							partialResults.addAll(itm.solveOneStep());
+							List<Function> dt = itm.solveOneStep();
+							partialResults.addAll(dt);
 						} else {
 							partialResults.add(itm);
 						}
@@ -71,6 +82,11 @@ public class Calculator {
 					
 				} else {
 					Collections.reverse(results);
+					// add elements to al, including duplicates
+					Set<Function> hs = new LinkedHashSet<>();
+					hs.addAll(results);
+					results.clear();
+					results.addAll(hs);
 					es.f2 = results;
 					for (Function rf : es.f2) {
 						rf.generateGraphics();
@@ -87,6 +103,11 @@ public class Calculator {
 			if (f instanceof Equation) {
 				List<Function> results = ((Equation)f).solve(letter);
 				Collections.reverse(results);
+				// add elements to al, including duplicates
+				Set<Function> hs = new LinkedHashSet<>();
+				hs.addAll(results);
+				results.clear();
+				results.addAll(hs);
 				es.f2 = results;
 				for (Function rf : es.f2) {
 					rf.generateGraphics();

src/org/warp/picalculator/math/MathematicalSymbols.java

@@ -1,7 +1,9 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math;
 
 import static org.warp.picalculator.Utils.concat;
 
+import org.warp.picalculator.Utils;
+
 public class MathematicalSymbols {
 	public static final String SUM = "+";
 	public static final String SUM_SUBTRACTION = "±";

src/org/warp/picalculator/math/SolveMethod.java

@@ -1,7 +1,9 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math;
 
 import java.util.ArrayList;
 
+import org.warp.picalculator.math.functions.equations.Equation;
+
 public interface SolveMethod {
 	public static final SolveMethod[] techniques = new SolveMethod[] {};
 

src/org/warp/picalculator/math/Variable.java

@@ -1,4 +1,4 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math;
 
 import org.nevec.rjm.Rational;
 

src/org/warp/picalculator/math/Variables.java

@@ -1,4 +1,4 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math;
 
 import java.math.BigInteger;
 import java.util.Comparator;
@@ -6,6 +6,7 @@ import java.util.Vector;
 
 import org.nevec.rjm.BigIntegerMath;
 import org.nevec.rjm.Rational;
+import org.warp.picalculator.Error;
 
 public class Variables {
 

src/org/warp/picalculator/math/functions/AnteriorFunction.java

@@ -1,13 +1,15 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions;
 
-import static org.warp.engine.Display.Render.getStringWidth;
+import static org.warp.picalculator.device.graphicengine.Display.Render.getStringWidth;
-import static org.warp.engine.Display.Render.glDrawStringLeft;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glDrawStringLeft;
 
 import java.util.List;
 
 import org.nevec.rjm.NumeroAvanzatoVec;
-import org.warp.device.PIDisplay;
+import org.warp.picalculator.Error;
-import org.warp.engine.Display;
+import org.warp.picalculator.Utils;
+import org.warp.picalculator.device.PIDisplay;
+import org.warp.picalculator.device.graphicengine.Display;
 
 import com.rits.cloning.Cloner;
 
@@ -106,4 +108,14 @@ public abstract class AnteriorFunction implements Function {
 	public void setSmall(boolean small) {
 		this.small = small;
 	}
+	
+	@Override
+	public int hashCode() {
+		return variable.hashCode()+883*getSymbol().hashCode();
+	}
+	
+	@Override
+	public boolean equals(Object o) {
+		return o != null && o.hashCode() == this.hashCode();
+	}
 }

src/org/warp/picalculator/math/functions/Division.java

@@ -1,20 +1,24 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions;
 
-import static org.warp.engine.Display.Render.getStringWidth;
+import static org.warp.picalculator.device.graphicengine.Display.Render.getStringWidth;
-import static org.warp.engine.Display.Render.glColor3f;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glColor3f;
-import static org.warp.engine.Display.Render.glDrawStringLeft;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glDrawStringLeft;
-import static org.warp.engine.Display.Render.glFillRect;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glFillRect;
 
 import java.util.ArrayList;
 import java.util.List;
 
 import org.nevec.rjm.NumeroAvanzatoVec;
-import org.warp.device.PIDisplay;
+import org.warp.picalculator.Error;
-import org.warp.engine.Display;
+import org.warp.picalculator.Errors;
+import org.warp.picalculator.Utils;
+import org.warp.picalculator.device.PIDisplay;
+import org.warp.picalculator.device.graphicengine.Display;
+import org.warp.picalculator.math.MathematicalSymbols;
 
-public class Division extends FunctionTwoValuesBase {
+public class Division extends FunctionTwoValues {
 
-	public Division(FunctionBase value1, FunctionBase value2) {
+	public Division(Function value1, Function value2) {
 		super(value1, value2);
 	}
 
@@ -66,7 +70,7 @@ public class Division extends FunctionTwoValuesBase {
 				if (cur2 >= size1) cur2 = 0;
 			}
 			for (Function[] f : results) {
-				result.add(new Division((FunctionBase)f[0], (FunctionBase)f[1]));
+				result.add(new Division((Function)f[0], (Function)f[1]));
 			}
 		}
 		stepsCount=-1;

src/org/warp/picalculator/math/functions/Expression.java

@@ -1,9 +1,9 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions;
 
-import static org.warp.engine.Display.Render.glColor3f;
-import static org.warp.engine.Display.Render.glDrawLine;
 import static org.warp.picalculator.Utils.ArrayToRegex;
 import static org.warp.picalculator.Utils.concat;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glColor3f;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glDrawLine;
 
 import java.math.BigDecimal;
 import java.math.BigInteger;
@@ -13,14 +13,20 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 import org.nevec.rjm.NumeroAvanzato;
+import org.warp.picalculator.Error;
+import org.warp.picalculator.Errors;
+import org.warp.picalculator.Utils;
+import org.warp.picalculator.math.MathematicalSymbols;
+import org.warp.picalculator.math.Variable;
+import org.warp.picalculator.math.Variables;
 
-public class Expression extends FunctionMultipleValuesBase {
+public class Expression extends FunctionMultipleValues {
 
 	public Expression() {
 		super();
 	}
 
-	public Expression(FunctionBase[] values) {
+	public Expression(Function[] values) {
 		super(values);
 	}
 
@@ -51,7 +57,7 @@ public class Expression extends FunctionMultipleValuesBase {
 			// If the expression is already a number:
 			// Se l'espressione è già un numero:
 			Number t = new Number(string);
-			setVariables(new FunctionBase[] { t });
+			setVariables(new Function[] { t });
 			Utils.debug.println(debugSpaces + "•Result:" + t.toString());
 		} else {
 			// Else prepare the expression:
@@ -180,7 +186,7 @@ public class Expression extends FunctionMultipleValuesBase {
 
 			// Convert the expression to a list of objects
 			Expression imputRawParenthesis = new Expression();
-			imputRawParenthesis.setVariables(new FunctionBase[] {});
+			imputRawParenthesis.setVariables(new Function[] {});
 			String tmp = "";
 			final String[] functions = concat(concat(concat(concat(MathematicalSymbols.functions(), MathematicalSymbols.parentheses()), MathematicalSymbols.signums(true, true)), MathematicalSymbols.variables()), MathematicalSymbols.genericSyntax());
 			for (int i = 0; i < processExpression.length(); i++) {
@@ -190,7 +196,7 @@ public class Expression extends FunctionMultipleValuesBase {
 
 					// Finds the type of function fron the following list
 					// Cerca il tipo di funzione tra le esistenti
-					FunctionBase f = null;
+					Function f = null;
 					switch (charI) {
 						case MathematicalSymbols.SUM:
 							f = new Sum(null, null);
@@ -254,7 +260,7 @@ public class Expression extends FunctionMultipleValuesBase {
 								// Fallback
 								NumeroAvanzato na = NumeroAvanzato.ONE;
 								Variables iy = na.getVariableY();
-								iy.variables.add(new Variable(charI.charAt(0), 1, 1));
+								iy.getVariablesList().add(new Variable(charI.charAt(0), 1, 1));
 								na = na.setVariableY(iy);
 								f = new Number(na);
 							} else {
@@ -333,7 +339,7 @@ public class Expression extends FunctionMultipleValuesBase {
 				if (imputRawParenthesis.variables[i] instanceof Expression) {
 					Expression par = (Expression) imputRawParenthesis.variables[i];
 					if (par.variables.length == 1) {
-						FunctionBase subFunz = par.variables[0];
+						Function subFunz = par.variables[0];
 						if (subFunz instanceof Expression || subFunz instanceof Number) {
 							imputRawParenthesis.variables[i] = subFunz;
 							Utils.debug.println(debugSpaces + "  •Useless parentheses removed");
@@ -345,10 +351,10 @@ public class Expression extends FunctionMultipleValuesBase {
 			// Inizia l'affinazione dell'espressione
 			Utils.debug.println(debugSpaces + "•Pushing classes...");
 
-			FunctionBase[] oldFunctionsArray = imputRawParenthesis.getVariables();
+			Function[] oldFunctionsArray = imputRawParenthesis.getVariables();
-			ArrayList<FunctionBase> oldFunctionsList = new ArrayList<FunctionBase>();
+			ArrayList<Function> oldFunctionsList = new ArrayList<Function>();
 			for (int i = 0; i < oldFunctionsArray.length; i++) {
-				FunctionBase funzione = oldFunctionsArray[i];
+				Function funzione = oldFunctionsArray[i];
 				if (funzione != null) {
 					//Affinazione
 					if (funzione instanceof Root) {
@@ -395,20 +401,20 @@ public class Expression extends FunctionMultipleValuesBase {
 					}
 					Utils.debug.println(debugSpaces + "  •Phase: "+step);
 					while (i < oldFunctionsList.size() && change == false && oldFunctionsList.size() > 1) {
-						FunctionBase funzioneTMP = oldFunctionsList.get(i);
+						Function funzioneTMP = oldFunctionsList.get(i);
-						if (funzioneTMP instanceof FunctionTwoValuesBase) {
+						if (funzioneTMP instanceof FunctionTwoValues) {
 							if (step != "SN Functions") {
 								if (
-										(step == "sums" && (funzioneTMP instanceof Sum || funzioneTMP instanceof SumSubtraction) == true && ((funzioneTMP instanceof AnteriorFunctionBase && ((AnteriorFunctionBase) funzioneTMP).variable == null) || (funzioneTMP instanceof FunctionTwoValuesBase && ((FunctionTwoValuesBase) funzioneTMP).variable1 == null && ((FunctionTwoValuesBase) funzioneTMP).variable2 == null) || (!(funzioneTMP instanceof AnteriorFunctionBase) && !(funzioneTMP instanceof FunctionTwoValuesBase))))
+										(step == "sums" && (funzioneTMP instanceof Sum || funzioneTMP instanceof SumSubtraction) == true && ((funzioneTMP instanceof AnteriorFunction && ((AnteriorFunction) funzioneTMP).variable == null) || (funzioneTMP instanceof FunctionTwoValues && ((FunctionTwoValues) funzioneTMP).variable1 == null && ((FunctionTwoValues) funzioneTMP).variable2 == null) || (!(funzioneTMP instanceof AnteriorFunction) && !(funzioneTMP instanceof FunctionTwoValues))))
 										||
 										(
 											step.equals("prioritary multiplications")
 											&&
 											(funzioneTMP instanceof PrioritaryMultiplication)
 											&&
-											((FunctionTwoValuesBase) funzioneTMP).variable1 == null
+											((FunctionTwoValues) funzioneTMP).variable1 == null
 											&&
-											((FunctionTwoValuesBase) funzioneTMP).variable2 == null
+											((FunctionTwoValues) funzioneTMP).variable2 == null
 										)
 										||
 										(
@@ -420,9 +426,9 @@ public class Expression extends FunctionMultipleValuesBase {
 												(funzioneTMP instanceof Division)
 											)
 											&&
-											((FunctionTwoValuesBase) funzioneTMP).variable1 == null
+											((FunctionTwoValues) funzioneTMP).variable1 == null
 											&&
-											((FunctionTwoValuesBase) funzioneTMP).variable2 == null
+											((FunctionTwoValues) funzioneTMP).variable2 == null
 										)
 										||
 										(
@@ -440,23 +446,23 @@ public class Expression extends FunctionMultipleValuesBase {
 											&&
 											(
 												(
-													funzioneTMP instanceof AnteriorFunctionBase
+													funzioneTMP instanceof AnteriorFunction
 													&&
-													((AnteriorFunctionBase) funzioneTMP).variable == null
+													((AnteriorFunction) funzioneTMP).variable == null
 												)
 												||
 												(
-													funzioneTMP instanceof FunctionTwoValuesBase
+													funzioneTMP instanceof FunctionTwoValues
 													&&
-													((FunctionTwoValuesBase) funzioneTMP).variable1 == null
+													((FunctionTwoValues) funzioneTMP).variable1 == null
 													&&
-													((FunctionTwoValuesBase) funzioneTMP).variable2 == null
+													((FunctionTwoValues) funzioneTMP).variable2 == null
 												)
 												||
 												(
-													!(funzioneTMP instanceof AnteriorFunctionBase)
+													!(funzioneTMP instanceof AnteriorFunction)
 													&&
-													!(funzioneTMP instanceof FunctionTwoValuesBase)
+													!(funzioneTMP instanceof FunctionTwoValues)
 												)
 											)
 										)
@@ -464,8 +470,8 @@ public class Expression extends FunctionMultipleValuesBase {
 									change = true;
 
 									if (i + 1 < oldFunctionsList.size() && i - 1 >= 0) {
-										((FunctionTwoValuesBase) funzioneTMP).setVariable1((FunctionBase) oldFunctionsList.get(i - 1));
+										((FunctionTwoValues) funzioneTMP).setVariable1((Function) oldFunctionsList.get(i - 1));
-										((FunctionTwoValuesBase) funzioneTMP).setVariable2((FunctionBase) oldFunctionsList.get(i + 1));
+										((FunctionTwoValues) funzioneTMP).setVariable2((Function) oldFunctionsList.get(i + 1));
 										oldFunctionsList.set(i, funzioneTMP);
 
 										// è importante togliere prima gli elementi
@@ -476,13 +482,13 @@ public class Expression extends FunctionMultipleValuesBase {
 
 										Utils.debug.println(debugSpaces + "  •Set variable to expression:" + funzioneTMP.getSymbol());
 										try {
-											Utils.debug.println(debugSpaces + "    " + "var1=" + ((FunctionTwoValuesBase) funzioneTMP).getVariable1().toString());
+											Utils.debug.println(debugSpaces + "    " + "var1=" + ((FunctionTwoValues) funzioneTMP).getVariable1().toString());
 										} catch (NullPointerException ex2) {}
 										try {
-											Utils.debug.println(debugSpaces + "    " + "var2=" + ((FunctionTwoValuesBase) funzioneTMP).getVariable2().toString());
+											Utils.debug.println(debugSpaces + "    " + "var2=" + ((FunctionTwoValues) funzioneTMP).getVariable2().toString());
 										} catch (NullPointerException ex2) {}
 										try {
-											Utils.debug.println(debugSpaces + "    " + "(result)=" + ((FunctionTwoValuesBase) funzioneTMP).toString());
+											Utils.debug.println(debugSpaces + "    " + "(result)=" + ((FunctionTwoValues) funzioneTMP).toString());
 										} catch (NullPointerException ex2) {}
 
 									} else {
@@ -490,15 +496,15 @@ public class Expression extends FunctionMultipleValuesBase {
 									}
 								}
 							}
-						} else if (funzioneTMP instanceof AnteriorFunctionBase) {
+						} else if (funzioneTMP instanceof AnteriorFunction) {
-							if ((step == "SN Functions" && ((AnteriorFunctionBase) funzioneTMP).variable == null)) {
+							if ((step == "SN Functions" && ((AnteriorFunction) funzioneTMP).variable == null)) {
 								if (i + 1 < oldFunctionsList.size()) {
-									FunctionBase nextFunc = oldFunctionsList.get(i + 1);
+									Function nextFunc = oldFunctionsList.get(i + 1);
-									if (nextFunc instanceof AnteriorFunctionBase && ((AnteriorFunctionBase)nextFunc).variable == null) {
+									if (nextFunc instanceof AnteriorFunction && ((AnteriorFunction)nextFunc).variable == null) {
 										
 									} else {
 										change = true;
-										((AnteriorFunctionBase) funzioneTMP).setVariable((FunctionBase) nextFunc);
+										((AnteriorFunction) funzioneTMP).setVariable((Function) nextFunc);
 										oldFunctionsList.set(i, funzioneTMP);
 
 										// è importante togliere prima gli elementi in
@@ -507,7 +513,7 @@ public class Expression extends FunctionMultipleValuesBase {
 										oldFunctionsList.remove(i + 1);
 
 										Utils.debug.println(debugSpaces + "  •Set variable to expression:" + funzioneTMP.getSymbol());
-										FunctionBase var = ((AnteriorFunctionBase) funzioneTMP).getVariable();
+										Function var = ((AnteriorFunction) funzioneTMP).getVariable();
 										if (var == null) {
 											Utils.debug.println(debugSpaces + "    " + "var=null");
 										} else {
@@ -563,7 +569,7 @@ public class Expression extends FunctionMultipleValuesBase {
 					if (f instanceof Number) {
 						ret.add(f);
 					} else {
-						ret.add(new Expression(new FunctionBase[]{(FunctionBase) f}));
+						ret.add(new Expression(new Function[]{(Function) f}));
 					}
 				}
 				stepsCount = -1;
@@ -578,7 +584,7 @@ public class Expression extends FunctionMultipleValuesBase {
 				if (f.getStepsCount() >= stepsCount - 1) {
 					List<Function> partial = f.solveOneStep();
 					for (Function fnc : partial) {
-						ret.add(new Expression(new FunctionBase[]{(FunctionBase) fnc}));
+						ret.add(new Expression(new Function[]{(Function) fnc}));
 					}
 				}
 			}

src/org/warp/picalculator/math/functions/Function.java

@@ -1,7 +1,9 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions;
 
 import java.util.List;
 
+import org.warp.picalculator.Error;
+
 public interface Function {
 	public String getSymbol();
 

src/org/warp/picalculator/math/functions/FunctionMultipleValues.java

@@ -1,4 +1,4 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions;
 
 import java.util.Arrays;
 import java.util.List;
@@ -103,4 +103,14 @@ public abstract class FunctionMultipleValues implements Function {
 	public void setSmall(boolean small) {
 		this.small = small;
 	}
+	
+	@Override
+	public int hashCode() {
+		return variables.hashCode()+883*getSymbol().hashCode();
+	}
+	
+	@Override
+	public boolean equals(Object o) {
+		return o != null && o.hashCode() == this.hashCode();
+	}
 }

src/org/warp/picalculator/math/functions/FunctionTwoValues.java

@@ -1,13 +1,15 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions;
 
-import static org.warp.engine.Display.Render.getStringWidth;
+import static org.warp.picalculator.device.graphicengine.Display.Render.getStringWidth;
-import static org.warp.engine.Display.Render.glDrawStringLeft;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glDrawStringLeft;
 
 import java.util.List;
 
 import org.nevec.rjm.Rational;
-import org.warp.device.PIDisplay;
+import org.warp.picalculator.Error;
-import org.warp.engine.Display;
+import org.warp.picalculator.Utils;
+import org.warp.picalculator.device.PIDisplay;
+import org.warp.picalculator.device.graphicengine.Display;
 
 import com.rits.cloning.Cloner;
 
@@ -17,7 +19,7 @@ public abstract class FunctionTwoValues implements Function {
 		setVariable2(value2);
 	}
 
-	protected Function variable1 = new Number(Rational.ZERO);
+	protected Function variable1 = (Function) new Number(Rational.ZERO);
 	protected int width;
 	protected int height;
 	protected int line;
@@ -31,7 +33,7 @@ public abstract class FunctionTwoValues implements Function {
 		variable1 = value;
 	}
 
-	protected Function variable2 = new Number(Rational.ZERO);
+	protected Function variable2 = (Function) new Number(Rational.ZERO);
 
 	public Function getVariable2() {
 		return variable2;
@@ -44,8 +46,20 @@ public abstract class FunctionTwoValues implements Function {
 	@Override
 	public abstract String getSymbol();
 	
+	protected int stepsCount = -1;
 	@Override
-	public abstract int getStepsCount();
+	public int getStepsCount() {
+		if (stepsCount == -1) {
+			int val1 = variable1.getStepsCount();
+			int val2 = variable2.getStepsCount();
+			if (val1 > val2) {
+				stepsCount = val1+1;
+			} else {
+				stepsCount = val2+1;
+			}
+		}
+		return stepsCount;
+	}
 	
 	@Override
 	public abstract List<Function> solveOneStep() throws Error;
@@ -145,4 +159,14 @@ public abstract class FunctionTwoValues implements Function {
 		}
 		return tl.getLine();
 	}
+	
+	@Override
+	public int hashCode() {
+		return variable1.hashCode()+7*variable2.hashCode()+883*getSymbol().hashCode();
+	}
+	
+	@Override
+	public boolean equals(Object o) {
+		return o != null && o.hashCode() == this.hashCode();
+	}
 }

src/org/warp/picalculator/math/functions/Multiplication.java

@@ -1,12 +1,17 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions;
 
 import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.List;
 
-public class Multiplication extends FunctionTwoValuesBase {
+import org.warp.picalculator.Error;
+import org.warp.picalculator.Errors;
+import org.warp.picalculator.math.MathematicalSymbols;
+import org.warp.picalculator.math.Variable;
 
-	public Multiplication(FunctionBase value1, FunctionBase value2) {
+public class Multiplication extends FunctionTwoValues {
+
+	public Multiplication(Function value1, Function value2) {
 		super(value1, value2);
 	}
 
@@ -54,7 +59,7 @@ public class Multiplication extends FunctionTwoValuesBase {
 				if (cur2 >= size1) cur2 = 0;
 			}
 			for (Function[] f : results) {
-				result.add(new Multiplication((FunctionBase)f[0], (FunctionBase)f[1]));
+				result.add(new Multiplication(f[0], f[1]));
 			}
 		}
 		stepsCount=-1;
@@ -103,14 +108,14 @@ public class Multiplication extends FunctionTwoValuesBase {
 				} else if (tmpVar[val] instanceof Expression) {
 					ok[0] = true;
 					ok[1] = true;
-				} else if (tmpVar[val] instanceof FunctionTwoValuesBase) {
+				} else if (tmpVar[val] instanceof FunctionTwoValues) {
 					if (val == 0) {
-						tmpVar[val] = ((FunctionTwoValuesBase) tmpVar[val]).variable2;
+						tmpVar[val] = ((FunctionTwoValues) tmpVar[val]).variable2;
 					} else {
-						tmpVar[val] = ((FunctionTwoValuesBase) tmpVar[val]).variable1;
+						tmpVar[val] = ((FunctionTwoValues) tmpVar[val]).variable1;
 					}
-				} else if (tmpVar[val] instanceof AnteriorFunctionBase) {
+				} else if (tmpVar[val] instanceof AnteriorFunction) {
-					tmpVar[val] = ((AnteriorFunctionBase) tmpVar[val]).variable;
+					tmpVar[val] = ((AnteriorFunction) tmpVar[val]).variable;
 				}
 			}
 		}

src/org/warp/picalculator/math/functions/Number.java

@@ -1,9 +1,9 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions;
 
-import static org.warp.engine.Display.Render.getStringWidth;
+import static org.warp.picalculator.device.graphicengine.Display.Render.getStringWidth;
-import static org.warp.engine.Display.Render.glColor3f;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glColor3f;
-import static org.warp.engine.Display.Render.glDrawStringLeft;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glDrawStringLeft;
-import static org.warp.engine.Display.Render.glFillRect;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glFillRect;
 
 import java.math.BigDecimal;
 import java.math.BigInteger;
@@ -15,12 +15,15 @@ import org.nevec.rjm.BigDecimalMath;
 import org.nevec.rjm.NumeroAvanzato;
 import org.nevec.rjm.NumeroAvanzatoVec;
 import org.nevec.rjm.Rational;
-import org.warp.device.PIDisplay;
+import org.warp.picalculator.Error;
-import org.warp.engine.Display;
+import org.warp.picalculator.Utils;
+import org.warp.picalculator.device.PIDisplay;
+import org.warp.picalculator.device.graphicengine.Display;
+import org.warp.picalculator.math.Variables;
 
 import com.rits.cloning.Cloner;
 
-public class Number extends FunctionBase {
+public class Number implements Function {
 
 	protected NumeroAvanzatoVec term = NumeroAvanzatoVec.ZERO;
 	protected int width;
@@ -395,6 +398,16 @@ public class Number extends FunctionBase {
 		return result;
 	}
 	
+	@Override
+	public int hashCode() {
+		return toString().hashCode();
+	}
+	
+	@Override
+	public boolean equals(Object o) {
+		return o != null && o.hashCode() == this.hashCode();
+	}
+
 	/*
 	 * @Override
 	 * public void draw(int x, int y, Graphics g) {

src/org/warp/picalculator/math/functions/Power.java

@@ -1,11 +1,15 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions;
 
 import java.util.ArrayList;
 import java.util.List;
 
-public class Power extends FunctionTwoValuesBase {
+import org.warp.picalculator.Error;
+import org.warp.picalculator.Errors;
+import org.warp.picalculator.math.MathematicalSymbols;
 
-	public Power(FunctionBase value1, FunctionBase value2) {
+public class Power extends FunctionTwoValues {
+
+	public Power(Function value1, Function value2) {
 		super(value1, value2);
 	}
 
@@ -34,7 +38,7 @@ public class Power extends FunctionTwoValuesBase {
 		}
 		ArrayList<Function> result = new ArrayList<>();
 		if (stepsCount == 1) {
-			result.add(((Number)variable1).pow((Number)variable2));
+			result.add((Function) ((Number)variable1).pow((Number)variable2));
 		} else {
 			List<Function> l1 = new ArrayList<Function>();
 			List<Function> l2 = new ArrayList<Function>();
@@ -66,7 +70,7 @@ public class Power extends FunctionTwoValuesBase {
 				if (cur2 >= size1) cur2 = 0;
 			}
 			for (Function[] f : results) {
-				result.add(new Power((FunctionBase)f[0], (FunctionBase)f[1]));
+				result.add(new Power((Function)f[0], (Function)f[1]));
 			}
 		}
 		stepsCount=-1;

src/org/warp/picalculator/math/functions/PrioritaryMultiplication.java

@@ -1,11 +1,15 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions;
 
 import java.util.ArrayList;
 import java.util.List;
 
-public class PrioritaryMultiplication extends FunctionTwoValuesBase {
+import org.warp.picalculator.Error;
+import org.warp.picalculator.Errors;
+import org.warp.picalculator.math.MathematicalSymbols;
 
-	public PrioritaryMultiplication(FunctionBase value1, FunctionBase value2) {
+public class PrioritaryMultiplication extends FunctionTwoValues {
+
+	public PrioritaryMultiplication(Function value1, Function value2) {
 		super(value1, value2);
 	}
 
@@ -53,7 +57,7 @@ public class PrioritaryMultiplication extends FunctionTwoValuesBase {
 				if (cur2 >= size1) cur2 = 0;
 			}
 			for (Function[] f : results) {
-				result.add(new PrioritaryMultiplication((FunctionBase)f[0], (FunctionBase)f[1]));
+				result.add(new PrioritaryMultiplication((Function)f[0], (Function)f[1]));
 			}
 		}
 		stepsCount=-1;

src/org/warp/picalculator/math/functions/Root.java

@@ -1,15 +1,18 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions;
 
-import static org.warp.engine.Display.Render.glDrawLine;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glDrawLine;
 
 import java.util.ArrayList;
 import java.util.List;
 
 import org.nevec.rjm.NumeroAvanzatoVec;
+import org.warp.picalculator.Error;
+import org.warp.picalculator.Errors;
+import org.warp.picalculator.math.MathematicalSymbols;
 
-public class Root extends FunctionTwoValuesBase {
+public class Root extends FunctionTwoValues {
 
-	public Root(FunctionBase value1, FunctionBase value2) {
+	public Root(Function value1, Function value2) {
 		super(value1, value2);
 	}
 
@@ -72,7 +75,7 @@ public class Root extends FunctionTwoValuesBase {
 				if (cur2 >= size1) cur2 = 0;
 			}
 			for (Function[] f : results) {
-				result.add(new Root((FunctionBase)f[0], (FunctionBase)f[1]));
+				result.add(new Root((Function)f[0], (Function)f[1]));
 			}
 		}
 		stepsCount=-1;

src/org/warp/picalculator/math/functions/RootSquare.java

@@ -1,14 +1,17 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions;
 
 import java.util.ArrayList;
 import java.util.List;
 
-import org.nevec.rjm.NumeroAvanzatoVec;
 import org.nevec.rjm.Rational;
+import org.warp.picalculator.Error;
+import org.warp.picalculator.Errors;
+import org.warp.picalculator.Utils;
+import org.warp.picalculator.math.MathematicalSymbols;
 
-public class RootSquare extends AnteriorFunctionBase {
+public class RootSquare extends AnteriorFunction {
 
-	public RootSquare(FunctionBase value) {
+	public RootSquare(Function value) {
 		super(value);
 	}
 
@@ -53,7 +56,7 @@ public class RootSquare extends AnteriorFunctionBase {
 			}
 			
 			for (Function f : l1) {
-				result.add(new RootSquare((FunctionBase)f));
+				result.add(new RootSquare((Function)f));
 			}
 		}
 		stepsCount=-1;

src/org/warp/picalculator/math/functions/Subtraction.java

@@ -1,11 +1,15 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions;
 
 import java.util.ArrayList;
 import java.util.List;
 
-public class Subtraction extends FunctionTwoValuesBase {
+import org.warp.picalculator.Error;
+import org.warp.picalculator.Errors;
+import org.warp.picalculator.math.MathematicalSymbols;
 
-	public Subtraction(FunctionBase value1, FunctionBase value2) {
+public class Subtraction extends FunctionTwoValues {
+
+	public Subtraction(Function value1, Function value2) {
 		super(value1, value2);
 	}
 
@@ -53,7 +57,7 @@ public class Subtraction extends FunctionTwoValuesBase {
 				if (cur2 >= size1) cur2 = 0;
 			}
 			for (Function[] f : results) {
-				result.add(new Subtraction((FunctionBase)f[0], (FunctionBase)f[1]));
+				result.add(new Subtraction((Function)f[0], (Function)f[1]));
 			}
 		}
 		stepsCount=-1;

src/org/warp/picalculator/math/functions/Sum.java

@@ -1,17 +1,21 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions;
 
-import static org.warp.engine.Display.Render.getStringWidth;
+import static org.warp.picalculator.device.graphicengine.Display.Render.getStringWidth;
-import static org.warp.engine.Display.Render.glDrawStringLeft;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glDrawStringLeft;
 
 import java.util.ArrayList;
 import java.util.List;
 
-import org.warp.device.PIDisplay;
+import org.warp.picalculator.Error;
-import org.warp.engine.Display;
+import org.warp.picalculator.Errors;
+import org.warp.picalculator.Utils;
+import org.warp.picalculator.device.PIDisplay;
+import org.warp.picalculator.device.graphicengine.Display;
+import org.warp.picalculator.math.MathematicalSymbols;
 
-public class Sum extends FunctionTwoValuesBase {
+public class Sum extends FunctionTwoValues {
 
-	public Sum(FunctionBase value1, FunctionBase value2) {
+	public Sum(Function value1, Function value2) {
 		super(value1, value2);
 	}
 
@@ -59,7 +63,7 @@ public class Sum extends FunctionTwoValuesBase {
 				if (cur2 >= size1) cur2 = 0;
 			}
 			for (Function[] f : results) {
-				result.add(new Sum((FunctionBase)f[0], (FunctionBase)f[1]));
+				result.add(new Sum((Function)f[0], (Function)f[1]));
 			}
 		}
 		stepsCount=-1;

src/org/warp/picalculator/math/functions/SumSubtraction.java

@@ -1,17 +1,21 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions;
 
-import static org.warp.engine.Display.Render.getStringWidth;
+import static org.warp.picalculator.device.graphicengine.Display.Render.getStringWidth;
-import static org.warp.engine.Display.Render.glDrawStringLeft;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glDrawStringLeft;
 
 import java.util.ArrayList;
 import java.util.List;
 
-import org.warp.device.PIDisplay;
+import org.warp.picalculator.Error;
-import org.warp.engine.Display;
+import org.warp.picalculator.Errors;
+import org.warp.picalculator.Utils;
+import org.warp.picalculator.device.PIDisplay;
+import org.warp.picalculator.device.graphicengine.Display;
+import org.warp.picalculator.math.MathematicalSymbols;
 
-public class SumSubtraction extends FunctionTwoValuesBase {
+public class SumSubtraction extends FunctionTwoValues {
 
-	public SumSubtraction(FunctionBase value1, FunctionBase value2) {
+	public SumSubtraction(Function value1, Function value2) {
 		super(value1, value2);
 	}
 
@@ -60,7 +64,7 @@ public class SumSubtraction extends FunctionTwoValuesBase {
 				if (cur2 >= size1) cur2 = 0;
 			}
 			for (Function[] f : results) {
-				result.add(new SumSubtraction((FunctionBase)f[0], (FunctionBase)f[1]));
+				result.add(new SumSubtraction(f[0], f[1]));
 			}
 		}
 		stepsCount=-1;

src/org/warp/picalculator/math/functions/equations/Equation.java

@@ -1,4 +1,4 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions.equations;
 
 import java.math.BigInteger;
 import java.util.ArrayList;
@@ -6,7 +6,14 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
-import org.nevec.rjm.NumeroAvanzatoVec;
+import org.warp.picalculator.Error;
+import org.warp.picalculator.Errors;
+import org.warp.picalculator.math.MathematicalSymbols;
+import org.warp.picalculator.math.SolveMethod;
+import org.warp.picalculator.math.functions.Function;
+import org.warp.picalculator.math.functions.FunctionTwoValues;
+import org.warp.picalculator.math.functions.Number;
+import org.warp.picalculator.math.functions.Subtraction;
 
 import com.rits.cloning.Cloner;
 
@@ -31,7 +38,7 @@ public class Equation extends FunctionTwoValues {
 			if (((Number)variable2).getTerm().isBigInteger(false) && ((Number)variable2).getTerm().toBigInteger(false).compareTo(new BigInteger("0")) == 0) {
 				result.add(this);
 			} else {
-				result.add(new Equation(new Subtraction((FunctionBase)variable1, (FunctionBase)variable2), new Number("0")));
+				result.add(new Equation(new Subtraction(variable1, variable2), new Number("0")));
 			}
 		} else {
 			List<Function> l1 = new ArrayList<Function>();
@@ -64,7 +71,7 @@ public class Equation extends FunctionTwoValues {
 				if (cur2 >= size1) cur2 = 0;
 			}
 			for (Function[] f : results) {
-				result.add(new Equation((FunctionBase)f[0], (FunctionBase)f[1]));
+				result.add(new Equation(f[0], f[1]));
 			}
 			stepsCount=-1;
 		}

src/org/warp/picalculator/math/functions/equations/EquationResult.java

@@ -1,7 +1,9 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions.equations;
 
 import java.math.BigInteger;
 
+import org.warp.picalculator.math.functions.Number;
+
 public class EquationResult {
 	public boolean isAnEquation = false;
 	public Number LR = new Number(new BigInteger("0"));

src/org/warp/picalculator/math/functions/equations/EquationsSystem.java

@@ -1,10 +1,14 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions.equations;
 
-import static org.warp.engine.Display.Render.glDrawLine;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glDrawLine;
 
 import java.util.ArrayList;
 import java.util.List;
 
+import org.warp.picalculator.Error;
+import org.warp.picalculator.math.functions.Function;
+import org.warp.picalculator.math.functions.FunctionMultipleValues;
+
 public class EquationsSystem extends FunctionMultipleValues {
 	static final int spacing = 2;
 	

src/org/warp/picalculator/math/functions/equations/EquationsSystemPart.java

@@ -1,10 +1,15 @@
-package org.warp.picalculator;
+package org.warp.picalculator.math.functions.equations;
 
-import static org.warp.engine.Display.Render.glColor3f;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glColor3f;
-import static org.warp.engine.Display.Render.glDrawLine;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glDrawLine;
 
 import java.util.List;
 
+import org.warp.picalculator.Error;
+import org.warp.picalculator.math.MathematicalSymbols;
+import org.warp.picalculator.math.functions.AnteriorFunction;
+import org.warp.picalculator.math.functions.Function;
+
 public class EquationsSystemPart extends AnteriorFunction {
 
 	public EquationsSystemPart(Equation equazione) {

src/org/warp/picalculator/screens/EmptyScreen.java

@@ -1,8 +1,8 @@
 package org.warp.picalculator.screens;
 
-import org.warp.device.Keyboard.Key;
+import org.warp.picalculator.device.PIDisplay;
-import org.warp.device.PIDisplay;
+import org.warp.picalculator.device.Keyboard.Key;
-import org.warp.engine.Screen;
+import org.warp.picalculator.device.graphicengine.Screen;
 
 public class EmptyScreen extends Screen {
 

src/org/warp/picalculator/screens/EquationScreen.java

@@ -1,20 +1,20 @@
 package org.warp.picalculator.screens;
 
-import static org.warp.engine.Display.Render.*;
+import static org.warp.picalculator.device.graphicengine.Display.Render.*;
 
 import java.io.PrintWriter;
 import java.io.StringWriter;
 import java.util.List;
 
-import org.warp.device.Keyboard.Key;
-import org.warp.device.PIDisplay;
-import org.warp.engine.Display;
-import org.warp.engine.Screen;
-import org.warp.picalculator.Calculator;
 import org.warp.picalculator.Error;
 import org.warp.picalculator.Errors;
-import org.warp.picalculator.Function;
 import org.warp.picalculator.Utils;
+import org.warp.picalculator.device.PIDisplay;
+import org.warp.picalculator.device.Keyboard.Key;
+import org.warp.picalculator.device.graphicengine.Display;
+import org.warp.picalculator.device.graphicengine.Screen;
+import org.warp.picalculator.math.Calculator;
+import org.warp.picalculator.math.functions.Function;
 
 public class EquationScreen extends Screen {
 

src/org/warp/picalculator/screens/MarioScreen.java

@@ -1,21 +1,21 @@
 package org.warp.picalculator.screens;
 
-import static org.warp.engine.Display.Render.getMatrixOfImage;
+import static org.warp.picalculator.device.graphicengine.Display.Render.getMatrixOfImage;
-import static org.warp.engine.Display.Render.glClearColor;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glClearColor;
-import static org.warp.engine.Display.Render.glDrawSkin;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glDrawSkin;
-import static org.warp.engine.Display.Render.glDrawStringLeft;
+import static org.warp.picalculator.device.graphicengine.Display.Render.glDrawStringLeft;
-import static org.warp.engine.Display.Render.setFont;
+import static org.warp.picalculator.device.graphicengine.Display.Render.setFont;
 
 import java.awt.image.BufferedImage;
 import java.io.IOException;
 
 import javax.imageio.ImageIO;
 
-import org.warp.device.Keyboard;
-import org.warp.device.Keyboard.Key;
-import org.warp.device.PIDisplay;
-import org.warp.engine.Screen;
 import org.warp.picalculator.Main;
+import org.warp.picalculator.device.Keyboard;
+import org.warp.picalculator.device.PIDisplay;
+import org.warp.picalculator.device.Keyboard.Key;
+import org.warp.picalculator.device.graphicengine.Screen;
 
 public class MarioScreen extends Screen {
 

src/org/warp/picalculator/screens/SolveEquationScreen.java

@@ -1,13 +1,12 @@
 package org.warp.picalculator.screens;
 
-import static org.warp.engine.Display.Render.*;
+import static org.warp.picalculator.device.graphicengine.Display.Render.*;
 
-import org.warp.device.Keyboard.Key;
-import org.warp.engine.Display;
-import org.warp.engine.Screen;
-import org.warp.picalculator.Calculator;
 import org.warp.picalculator.Error;
 import org.warp.picalculator.Main;
+import org.warp.picalculator.device.Keyboard.Key;
+import org.warp.picalculator.device.graphicengine.Screen;
+import org.warp.picalculator.math.Calculator;
 
 public class SolveEquationScreen extends Screen {