ScriptREPL: add option to use REPL quietly

Now you can call initialize(false) and it will skip the greeting. And
you can call lang(ScriptLanguage) to pass the language directly, in
which case it will not emit the notification about the language change.

Author: ctrueden

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

@@ -134,22 +134,38 @@ public void loop(final InputStream in) throws IOException {
 		}
 	}
 
-	/** Outputs a greeting, and sets up the initial language of the REPL. */
+	/**
+	 * Outputs a greeting, and sets up the initial language and variables of the
+	 * REPL.
+	 */
 	public void initialize() {
-		out.println("Welcome to the SciJava REPL!");
-		out.println();
-		help();
+		initialize(true);
+	}
+
+	/**
+	 * Sets up the initial language and variables of the REPL.
+	 * 
+	 * @param verbose Whether to output an initial greeting.
+	 */
+	public void initialize(final boolean verbose) {
+		if (verbose) {
+			out.println("Welcome to the SciJava REPL!");
+			out.println();
+			help();
+		}
 		final List<ScriptLanguage> langs = getInterpretedLanguages();
-		if (langs.isEmpty()) {
-			out.println("--------------------------------------------------------------");
-			out.println("Uh oh! There are no SciJava script languages available!");
-			out.println("Are any on your classpath? E.g.: org.scijava:scripting-groovy?");
-			out.println("--------------------------------------------------------------");
+		if (verbose) {
+			if (langs.isEmpty()) {
+				out.println("--------------------------------------------------------------");
+				out.println("Uh oh! There are no SciJava script languages available!");
+				out.println("Are any on your classpath? E.g.: org.scijava:scripting-groovy?");
+				out.println("--------------------------------------------------------------");
+				out.println();
+				return;
+			}
+			out.println("Have fun!");
 			out.println();
-			return;
 		}
-		out.println("Have fun!");
-		out.println();
 		lang(langs.get(0).getLanguageName());
 		populateBindings(interpreter.getBindings());
 	}
@@ -249,6 +265,17 @@ public void lang(final String langName) {
 			out.println("No such language: " + langName);
 			return;
 		}
+		lang(language);
+		out.println("language -> " + interpreter.getLanguage().getLanguageName());
+	}
+
+	/**
+	 * Creates a new {@link ScriptInterpreter} to interpret statements, preserving
+	 * existing variables from the previous interpreter.
+	 * 
+	 * @param language The script language of the new interpreter.
+	 */
+	public void lang(final ScriptLanguage language) {
 		final ScriptInterpreter newInterpreter =
 			new DefaultScriptInterpreter(language);
 
@@ -259,8 +286,6 @@ public void lang(final String langName) {
 		catch (final Throwable t) {
 			t.printStackTrace(out);
 		}
-		out.println("language -> " +
-			newInterpreter.getLanguage().getLanguageName());
 		interpreter = newInterpreter;
 	}