ScriptInfo: append return value if no outputs

We want the return value to be an easy way to return a single, untyped
(Object) output. This is quite useful for the "lazy" (I mean "elegant")
script writer. But for those consuming scripts, it is annoying to always
have to deal with this extra "result" output.

As a compromise, let's only append the "result" output if:
A) no other outputs were declared; and
B) "result" was not declared as an input either.

Author: ctrueden

src/main/java/org/scijava/script/ScriptInfo.java

@@ -413,7 +413,12 @@ private <T> void addItem(final String name, final Class<T> type,
 			assignAttribute(item, key, value);
 		}
 		if (item.isInput()) registerInput(item);
-		if (item.isOutput()) registerOutput(item);
+		if (item.isOutput()) {
+			registerOutput(item);
+			// NB: Only append the return value as an extra
+			// output when no explicit outputs are declared.
+			appendReturnValue = false;
+		}
 	}
 
 	private <T> void assignAttribute(final DefaultMutableModuleItem<T> item,

src/test/java/org/scijava/script/ScriptInfoTest.java

@@ -97,7 +97,7 @@ public void testNoisyParameters() throws Exception {
 		final ScriptModule scriptModule =
 			scriptService.run("hello.bsizes", script, true).get();
 
-		final Object output = scriptModule.getOutput("result");
+		final Object output = scriptModule.getReturnValue();
 
 		if (output == null) fail("null result");
 		else if (!(output instanceof Integer)) {
@@ -170,18 +170,14 @@ public void testParameters() {
 		assertItem("buffer", StringBuilder.class, null, ItemIO.BOTH, true, true,
 			null, null, null, null, null, null, null, null, noChoices, buffer);
 
-		final ModuleItem<?> result = info.getOutput("result");
-		assertItem("result", Object.class, null, ItemIO.OUTPUT, true, true, null,
-			null, null, null, null, null, null, null, noChoices, result);
-
 		int inputCount = 0;
 		final ModuleItem<?>[] inputs = { log, sliderValue, animal, buffer };
 		for (final ModuleItem<?> inItem : info.inputs()) {
 			assertSame(inputs[inputCount++], inItem);
 		}
 
 		int outputCount = 0;
-		final ModuleItem<?>[] outputs = { buffer, result };
+		final ModuleItem<?>[] outputs = { buffer };
 		for (final ModuleItem<?> outItem : info.outputs()) {
 			assertSame(outputs[outputCount++], outItem);
 		}