Handles Error

Author: seva-luchianov

src/javacalculus/evaluator/CalcLN.java

@@ -1,74 +1,77 @@
-/**
- * 
- */
-package javacalculus.evaluator;
-
-import javacalculus.core.CALC;
-import javacalculus.evaluator.extend.Calc1ParamFunctionEvaluator;
-import javacalculus.struct.CalcDouble;
-import javacalculus.struct.CalcFraction;
-import javacalculus.struct.CalcFunction;
-import javacalculus.struct.CalcInteger;
-import javacalculus.struct.CalcObject;
-import javacalculus.struct.CalcSymbol;
-
-/**
- * Natural Logarithm evaluator. Supports stable treatment of border and nondomain input.
- * @author Duyun Chen <A HREF="mailto:[email protected]">[[email protected]]</A>,
- * Seth Shannin <A HREF="mailto:[email protected]">[[email protected]]</A>
- *  
- *
- */
-public class CalcLN extends Calc1ParamFunctionEvaluator {
-	
-	@Override
-	protected CalcObject evaluateObject(CalcObject input) {
-		CalcDouble E = null;
-		try {
-			E = (CalcDouble)CALC.E.evaluate();
-		}
-		catch (Exception e) {
-			e.printStackTrace();
-		}
-		if (input.equals(E)) {
-			return CALC.ONE;
-		}
-		if (input.equals(CALC.ONE)) {
-			return CALC.ZERO;
-		}
-		if (input.equals(CALC.ZERO)) {
-			return CALC.NEG_INFINITY;
-		}
-		return null;
-	}
-	
-	@Override
-	protected CalcObject evaluateDouble(CalcDouble input) {
-		return new CalcDouble(Math.log(input.doubleValue()));
-	}
-
-	@Override
-	protected CalcObject evaluateFraction(CalcFraction input) {
-		//TODO decide whether ln(x/y) should evaluate to ln(x)-ln(y)
-		return CALC.LN.createFunction(input);
-	}
-
-	@Override
-	protected CalcObject evaluateFunction(CalcFunction input) {
-		//TODO make this more flexible?
-		return CALC.LN.createFunction(input);
-	}
-
-	@Override
-	protected CalcObject evaluateInteger(CalcInteger input) {
-		return new CalcDouble(Math.log(input.bigIntegerValue().intValue()));
-	}
-
-	
-	@Override
-	protected CalcObject evaluateSymbol(CalcSymbol input) {
-		//cannot evaluate symbols, so just return the original function
-		return CALC.LN.createFunction(input);
-	}
-
-}
+/**
+ * 
+ */
+package javacalculus.evaluator;
+
+import javacalculus.core.CALC;
+import javacalculus.evaluator.extend.Calc1ParamFunctionEvaluator;
+import javacalculus.struct.CalcDouble;
+import javacalculus.struct.CalcFraction;
+import javacalculus.struct.CalcFunction;
+import javacalculus.struct.CalcInteger;
+import javacalculus.struct.CalcObject;
+import javacalculus.struct.CalcSymbol;
+
+/**
+ * Natural Logarithm evaluator. Supports stable treatment of border and nondomain input.
+ * @author Duyun Chen <A HREF="mailto:[email protected]">[[email protected]]</A>,
+ * Seth Shannin <A HREF="mailto:[email protected]">[[email protected]]</A>
+ *  
+ *
+ */
+public class CalcLN extends Calc1ParamFunctionEvaluator {
+	
+	@Override
+	protected CalcObject evaluateObject(CalcObject input) {
+		CalcDouble E = null;
+		try {
+			E = (CalcDouble)CALC.E.evaluate();
+		}
+		catch (Exception e) {
+			e.printStackTrace();
+		}
+		if (input.equals(E)) {
+			return CALC.ONE;
+		}
+		if (input.equals(CALC.ONE)) {
+			return CALC.ZERO;
+		}
+		if (input.equals(CALC.ZERO)) {
+			return CALC.NEG_INFINITY;
+		}
+		return null;
+	}
+	
+	@Override
+	protected CalcObject evaluateDouble(CalcDouble input) {
+		return new CalcDouble(Math.log(input.doubleValue()));
+	}
+
+	@Override
+	protected CalcObject evaluateFraction(CalcFraction input) {
+		//TODO decide whether ln(x/y) should evaluate to ln(x)-ln(y)
+		return CALC.LN.createFunction(input);
+	}
+
+	@Override
+	protected CalcObject evaluateFunction(CalcFunction input) {
+		//TODO make this more flexible?
+		return CALC.LN.createFunction(input);
+	}
+
+	@Override
+	protected CalcObject evaluateInteger(CalcInteger input) {
+		return new CalcDouble(Math.log(input.bigIntegerValue().intValue()));
+	}
+
+	
+	@Override
+    protected CalcObject evaluateSymbol(CalcSymbol input) {
+        if (input.equals(CALC.ERROR)) {
+            return CALC.ERROR;
+        }
+        //cannot evaluate symbols, so just return the original function
+        return CALC.LN.createFunction(input);
+    }
+
+}