Add factory method for IonizeFailure in FusionIo.

runtime/src/main/java/dev/ionfusion/fusion/BaseValue.java

@@ -6,6 +6,7 @@
 import static dev.ionfusion.fusion.FusionBool.falseBool;
 import static dev.ionfusion.fusion.FusionBool.makeBool;
 import static dev.ionfusion.fusion.FusionBool.trueBool;
+import static dev.ionfusion.fusion.FusionIo.makeIonizeError;
 import static dev.ionfusion.fusion.FusionIo.safeWriteToString;
 import static dev.ionfusion.fusion.FusionValue.sameAnnotations;
 
@@ -127,7 +128,7 @@ SyntaxValue datumToSyntaxMaybe(Evaluator eval, SourceLocation loc)
     void ionize(Evaluator eval, IonWriter out)
         throws IOException, IonException, FusionException
     {
-        throw new IonizeFailure(this);
+        throw makeIonizeError(eval, this);
     }
 
 
@@ -212,7 +213,7 @@ IonValue copyToIonValue(Evaluator eval, ValueFactory factory,
     {
         if (throwOnConversionFailure)
         {
-            throw new IonizeFailure(this);
+            throw makeIonizeError(eval, this);
         }
 
         return null;

runtime/src/main/java/dev/ionfusion/fusion/FusionIo.java

@@ -104,7 +104,7 @@ static void dispatchIonize(Evaluator eval, IonWriter out, Object value)
         }
         catch (ClassCastException e)
         {
-            throw new IonizeFailure(value);
+            throw makeIonizeError(eval, value);
         }
 
         fv.ionize(eval, out);
@@ -208,6 +208,14 @@ static Object read(Evaluator eval, IonReader reader)
     // Basic output procedures
 
 
+    static ContractException makeIonizeError(Evaluator eval, Object unIonizableValue)
+    {
+        String message = "Cannot ionize non-Ionizable data: " +
+                         safeWriteToString(eval, unIonizableValue);
+        return new IonizeFailure(message, unIonizableValue);
+    }
+
+
     /**
      * Writes an Ion representation of a value.
      * An exception is thrown if the value contains any non-Ion data

runtime/src/main/java/dev/ionfusion/fusion/FusionSexp.java

@@ -11,6 +11,7 @@
 import static dev.ionfusion.fusion.FusionCompare.EqualityTier.TIGHT_EQUAL;
 import static dev.ionfusion.fusion.FusionIo.dispatchIonize;
 import static dev.ionfusion.fusion.FusionIo.dispatchWrite;
+import static dev.ionfusion.fusion.FusionIo.makeIonizeError;
 import static dev.ionfusion.fusion.FusionSymbol.BaseSymbol.internSymbols;
 import static dev.ionfusion.fusion.FusionVoid.voidValue;
 
@@ -991,7 +992,7 @@ else if (tail instanceof EmptySexp)
                 }
                 else if (throwOnConversionFailure)
                 {
-                    throw new IonizeFailure(this);
+                    throw makeIonizeError(eval, this);
                 }
                 else
                 {
@@ -1057,7 +1058,7 @@ else if (tail instanceof EmptySexp)
                 }
                 else
                 {
-                    throw new IonizeFailure(this);
+                    throw makeIonizeError(eval, this);
                 }
             }
             out.stepOut();

runtime/src/main/java/dev/ionfusion/fusion/FusionValue.java

@@ -3,6 +3,7 @@
 
 package dev.ionfusion.fusion;
 
+import static dev.ionfusion.fusion.FusionIo.makeIonizeError;
 import static dev.ionfusion.fusion._private.FusionUtils.EMPTY_OBJECT_ARRAY;
 import static dev.ionfusion.fusion._private.FusionUtils.EMPTY_STRING_ARRAY;
 
@@ -336,7 +337,7 @@ static IonValue copyToIonValue(Evaluator    eval,
 
         if (throwOnConversionFailure)
         {
-            throw new IonizeFailure(value);
+            throw makeIonizeError(eval, value);
         }
 
         return null;

runtime/src/main/java/dev/ionfusion/fusion/IonizeFailure.java

@@ -3,9 +3,6 @@
 
 package dev.ionfusion.fusion;
 
-import static dev.ionfusion.fusion.FusionIo.safeWrite;
-import java.io.IOException;
-
 /**
  * Indicates a failure to convert a Fusion value into Ion.
  */
@@ -15,19 +12,10 @@ final class IonizeFailure
 {
     private final Object myUnIonizableValue;
 
-    IonizeFailure(Object unIonizableValue)
+    IonizeFailure(String message, Object unIonizableValue)
     {
-        super(null);
+        super(message);
 
         myUnIonizableValue = unIonizableValue;
     }
-
-
-    @Override
-    void displayMessage(Evaluator eval, Appendable out)
-        throws IOException, FusionException
-    {
-        out.append("Cannot ionize non-Ionizable data: ");
-        safeWrite(eval, out, myUnIonizableValue);
-    }
 }