POC for context buffers

src/main/java/ortus/boxlang/runtime/BoxRuntime.java

@@ -504,15 +504,19 @@ public void executeTemplate( BoxTemplate template, IBoxContext context ) {
 
 		IBoxContext scriptingContext = ensureContextWithVariables( context );
 
-		// Fire!!!
-		template.invoke( scriptingContext );
-
-		// Debugging Timer
-		instance.logger.atDebug().log(
-		    "Executed template [{}] in [{}] ms",
-		    template.getRunnablePath(),
-		    timerUtil.stopAndGetMillis( "execute-" + template.hashCode() )
-		);
+		try {
+			// Fire!!!
+			template.invoke( scriptingContext );
+		} finally {
+			scriptingContext.flushBuffer();
+
+			// Debugging Timer
+			instance.logger.atDebug().log(
+			    "Executed template [{}] in [{}] ms",
+			    template.getRunnablePath(),
+			    timerUtil.stopAndGetMillis( "execute-" + template.hashCode() )
+			);
+		}
 	}
 
 	/**
@@ -543,6 +547,7 @@ public Object executeStatement( String source, IBoxContext context ) {
 			// Fire!!!
 			return scriptRunnable.invoke( scriptingContext );
 		} finally {
+			scriptingContext.flushBuffer();
 			// Debugging Timer
 			instance.logger.atDebug().log(
 			    "Executed source  [{}] ms",
@@ -576,15 +581,18 @@ public void executeSource( String source, IBoxContext context ) {
 		instance.logger.atDebug().log( "Executing source " );
 
 		IBoxContext scriptingContext = ensureContextWithVariables( context );
-		// Fire!!!
-		scriptRunnable.invoke( scriptingContext );
-
-		// Debugging Timer
-		instance.logger.atDebug().log(
-		    "Executed source  [{}] ms",
-		    timerUtil.stopAndGetMillis( "execute-" + source.hashCode() )
-		);
+		try {
+			// Fire!!!
+			scriptRunnable.invoke( scriptingContext );
+		} finally {
+			scriptingContext.flushBuffer();
 
+			// Debugging Timer
+			instance.logger.atDebug().log(
+			    "Executed source  [{}] ms",
+			    timerUtil.stopAndGetMillis( "execute-" + source.hashCode() )
+			);
+		}
 	}
 
 	/**

src/main/java/ortus/boxlang/runtime/bifs/global/system/WriteOutput.java

@@ -0,0 +1,53 @@
+/**
+ * [BoxLang]
+ *
+ * Copyright [2023] [Ortus Solutions, Corp]
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package ortus.boxlang.runtime.bifs.global.system;
+
+import ortus.boxlang.runtime.bifs.BIF;
+import ortus.boxlang.runtime.bifs.BoxBIF;
+import ortus.boxlang.runtime.context.IBoxContext;
+import ortus.boxlang.runtime.scopes.ArgumentsScope;
+import ortus.boxlang.runtime.scopes.Key;
+import ortus.boxlang.runtime.types.Argument;
+
+@BoxBIF
+@BoxBIF( alias = "echo" )
+public class WriteOutput extends BIF {
+
+	/**
+	 * Constructor
+	 */
+	public WriteOutput() {
+		super();
+		declaredArguments = new Argument[] {
+		    new Argument( true, "any", Key.message )
+		};
+	}
+
+	/**
+	 * Print a message with line break to the buffer
+	 *
+	 * @param context   The context in which the BIF is being invoked.
+	 * @param arguments Argument scope for the BIF.
+	 *
+	 * @argument.message The message to print
+	 */
+	public Object invoke( IBoxContext context, ArgumentsScope arguments ) {
+		context.writeToBuffer( arguments.get( Key.message ) );
+		return null;
+	}
+}

src/main/java/ortus/boxlang/runtime/context/BaseBoxContext.java

@@ -25,6 +25,7 @@
 import ortus.boxlang.runtime.BoxRuntime;
 import ortus.boxlang.runtime.bifs.BIFDescriptor;
 import ortus.boxlang.runtime.dynamic.casters.FunctionCaster;
+import ortus.boxlang.runtime.dynamic.casters.StringCaster;
 import ortus.boxlang.runtime.loader.ImportDefinition;
 import ortus.boxlang.runtime.runnables.BoxTemplate;
 import ortus.boxlang.runtime.runnables.ITemplateRunnable;
@@ -64,6 +65,8 @@ public class BaseBoxContext implements IBoxContext {
 
 	protected LinkedHashMap<Query, Integer>	queryLoops	= new LinkedHashMap<Query, Integer>();
 
+	protected StringBuffer					buffer		= new StringBuffer();
+
 	/**
 	 * Creates a new execution context with a bounded execution template and parent context
 	 *
@@ -525,4 +528,50 @@ public void incrementQueryLoop( Query query ) {
 		queryLoops.put( query, queryLoops.get( query ) + 1 );
 	}
 
+	/**
+	 * Write output to this buffer. Any input object will be converted to a string
+	 * 
+	 * @param o The object to write
+	 * 
+	 * @return This context
+	 */
+	public IBoxContext writeToBuffer( Object o ) {
+		buffer.append( StringCaster.cast( o ) );
+		return this;
+	}
+
+	/**
+	 * Flush the buffer to the output stream and then clears the local buffers
+	 * 
+	 * @return This context
+	 */
+	public IBoxContext flushBuffer() {
+		if ( hasParent() ) {
+			synchronized ( buffer ) {
+				getParent().writeToBuffer( buffer.toString() );
+				clearBuffer();
+			}
+		}
+		return this;
+	}
+
+	/**
+	 * Clear the buffer
+	 * 
+	 * @return This context
+	 */
+	public IBoxContext clearBuffer() {
+		buffer.setLength( 0 );
+		return this;
+	}
+
+	/**
+	 * Get the buffer
+	 * 
+	 * @return
+	 */
+	public StringBuffer getBuffer() {
+		return buffer;
+	}
+
 }

src/main/java/ortus/boxlang/runtime/context/IBoxContext.java

@@ -305,4 +305,37 @@ public record ScopeSearchResult( IScope scope, Object value ) {
 	 * @param query The query to increment
 	 */
 	public void incrementQueryLoop( Query query );
+
+	/**
+	 * Write output to this buffer. Any input object will be converted to a string
+	 * 
+	 * @param o The object to write
+	 * 
+	 * @return This context
+	 */
+	public IBoxContext writeToBuffer( Object o );
+
+	/**
+	 * Flush the buffer to the output stream. The default implementation simply flushes the buffer in this context
+	 * to its parent context. Different "top level" buffers can decide what they want to do with the buffer.
+	 * i.e. Scripting sends to the console, Web sends to HTTP response stream, etc.
+	 * 
+	 * @return This context
+	 */
+	public IBoxContext flushBuffer();
+
+	/**
+	 * Clear the buffer
+	 * 
+	 * @return This context
+	 */
+	public IBoxContext clearBuffer();
+
+	/**
+	 * Get the buffer
+	 * 
+	 * @return
+	 */
+	public StringBuffer getBuffer();
+
 }

src/main/java/ortus/boxlang/runtime/context/ScriptingBoxContext.java

@@ -207,4 +207,24 @@ public IScope getDefaultAssignmentScope() {
 		return variablesScope;
 	}
 
+	/**
+	 * Flush the buffer to the output stream
+	 * 
+	 * @return This context
+	 */
+	public IBoxContext flushBuffer() {
+		if ( hasParent() ) {
+			getParent().writeToBuffer( buffer.toString() );
+		}
+		String output;
+		synchronized ( buffer ) {
+			output = buffer.toString();
+			clearBuffer();
+		}
+		// If a scripting context is our top-level context, we flush to the console.
+		System.out.print( output );
+
+		return this;
+	}
+
 }

src/main/java/ortus/boxlang/runtime/scopes/Key.java

@@ -64,6 +64,7 @@ public class Key {
 	public static final Key	missingMethodName		= Key.of( "missingMethodName" );
 	public static final Key	missingMethodArguments	= Key.of( "missingMethodArguments" );
 	public static final Key	accessors				= Key.of( "accessors" );
+	public static final Key	output					= Key.of( "output" );
 
 	public static final Key	contains				= Key.of( "contains" );
 	public static final Key	find					= Key.of( "find" );

src/main/java/ortus/boxlang/runtime/types/Function.java

@@ -25,6 +25,7 @@
 import ortus.boxlang.runtime.context.FunctionBoxContext;
 import ortus.boxlang.runtime.context.IBoxContext;
 import ortus.boxlang.runtime.context.LambdaBoxContext;
+import ortus.boxlang.runtime.dynamic.casters.BooleanCaster;
 import ortus.boxlang.runtime.dynamic.casters.CastAttempt;
 import ortus.boxlang.runtime.dynamic.casters.GenericCaster;
 import ortus.boxlang.runtime.runnables.IFunctionRunnable;
@@ -149,6 +150,11 @@ public Object invoke( FunctionBoxContext context ) {
 		data.put( "result", result );
 		runtime.announce( "postFunctionInvoke", data );
 
+		// If output=true, then flush any content in buffer
+		if ( BooleanCaster.cast( getAnnotations().getOrDefault( Key.output, false ) ) ) {
+			context.flushBuffer();
+		}
+
 		return data.get( "result" );
 	}