Refactored to implement visitor pattern in prettyPrint and toBytes. #7.

src/main/java/com/webcodepro/applecommander/util/applesoft/Line.java

@@ -1,13 +1,11 @@
 package com.webcodepro.applecommander.util.applesoft;
 
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.PrintStream;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.function.Consumer;
 
 /** An AppleSoft BASIC Line representation. */
-public class Line {
+public class Line implements Consumer<Visitor> {
 	public final int lineNumber;
 	public final List<Statement> statements = new ArrayList<>();
 	
@@ -15,34 +13,8 @@ public class Line {
 		this.lineNumber = lineNumber;
 	}
 	
-	public void prettyPrint(PrintStream ps) {
-		boolean first = true;
-		for (Statement statement : statements) {
-			if (first) {
-				first = false;
-				ps.printf("%5d ", lineNumber);
-			} else {
-				ps.printf("%5s ", ":");
-			}
-			statement.prettyPrint(ps);
-			ps.println();
-		}
-	}
-
-	public int toBytes(int address, ByteArrayOutputStream os) throws IOException {
-		ByteArrayOutputStream tmp = new ByteArrayOutputStream();
-		for (Statement stmt : statements) {
-			if (tmp.size() > 0) tmp.write(':');
-			stmt.toBytes(tmp);
-		}
-		
-		int nextAddress = address + tmp.size() + 5;
-		os.write(nextAddress);
-		os.write(nextAddress >> 8);
-		os.write(lineNumber);
-		os.write(lineNumber >> 8);
-		tmp.writeTo(os);
-		os.write(0x00);
-		return nextAddress;
+	@Override
+	public void accept(Visitor t) {
+		t.visit(this);
 	}
 }

src/main/java/com/webcodepro/applecommander/util/applesoft/Program.java

@@ -1,26 +1,15 @@
 package com.webcodepro.applecommander.util.applesoft;
 
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.PrintStream;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.function.Consumer;
 
 /** A Program is a series of lines. */
-public class Program {
+public class Program implements Consumer<Visitor> {
 	public final List<Line> lines = new ArrayList<>();
 	
-	public void prettyPrint(PrintStream ps) {
-		for (Line line : lines) {
-			line.prettyPrint(ps);
-		}
-	}
-
-	public byte[] toBytes(int address) throws IOException {
-		ByteArrayOutputStream os = new ByteArrayOutputStream();
-		for (Line line : lines) address = line.toBytes(address, os);
-		os.write(0x00);
-		os.write(0x00);
-		return os.toByteArray();
+	@Override
+	public void accept(Visitor t) {
+		t.visit(this);
 	}
 }

src/main/java/com/webcodepro/applecommander/util/applesoft/Statement.java

@@ -1,22 +1,15 @@
 package com.webcodepro.applecommander.util.applesoft;
 
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.PrintStream;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.function.Consumer;
 
 /** A Statement is simply a series of Tokens. */
-public class Statement {
+public class Statement implements Consumer<Visitor> {
 	public final List<Token> tokens = new ArrayList<>();
 	
-	public void prettyPrint(PrintStream ps) {
-		for (Token token : tokens) {
-			token.prettyPrint(ps);
-		}
-	}
-
-	public void toBytes(ByteArrayOutputStream os) throws IOException {
-		for (Token t : tokens) t.toBytes(os);
+	@Override
+	public void accept(Visitor t) {
+		t.visit(this);
 	}
 }

src/main/java/com/webcodepro/applecommander/util/applesoft/Token.java

@@ -1,16 +1,13 @@
 package com.webcodepro.applecommander.util.applesoft;
 
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.PrintStream;
-import java.util.Optional;
+import java.util.function.Consumer;
 
 /**
  * A Token in the classic compiler sense, in that this represents a component of the application.
  * 
  * @author rob
  */
-public class Token {
+public class Token implements Consumer<Visitor> {
 	public final int line;
 	public final Type type;
 	public final ApplesoftKeyword keyword;
@@ -25,6 +22,10 @@ public class Token {
 		this.text = text;
 	}
 	@Override
+	public void accept(Visitor t) {
+		t.visit(this);
+	}
+	@Override
 	public String toString() {
 		switch (type) {
 		case EOL:
@@ -38,72 +39,6 @@ public class Token {
 		}
 	}
 	
-	public void prettyPrint(PrintStream ps) {
-		switch (type) {
-		case EOL:
-			ps.print("<EOL>");
-			break;
-		case COMMENT:
-			ps.printf(" REM %s", text);
-			break;
-		case STRING:
-			ps.printf("\"%s\"", text);
-			break;
-		case KEYWORD:
-			ps.printf(" %s ", keyword.text);
-			break;
-		case IDENT:
-		case SYNTAX:
-			ps.print(text);
-			break;
-		case NUMBER:
-			if (Math.rint(number) == number) {
-				ps.print(number.intValue());
-			} else {
-				ps.print(number);
-			}
-			break;
-		}
-	}
-
-	public void toBytes(ByteArrayOutputStream os) throws IOException {
-		switch (type) {
-		case COMMENT:
-			os.write(ApplesoftKeyword.REM.code);
-			os.write(text.getBytes());
-			break;
-		case EOL:
-			os.write(0x00);
-			break;
-		case IDENT:
-			os.write(text.getBytes());
-			break;
-		case KEYWORD:
-			os.write(keyword.code);
-			break;
-		case NUMBER:
-			if (Math.rint(number) == number) {
-				os.write(Integer.toString(number.intValue()).getBytes());
-			} else {
-				os.write(Double.toString(number).getBytes());
-			}
-			break;
-		case STRING:
-			os.write('"');
-			os.write(text.getBytes());
-			os.write('"');
-			break;
-		case SYNTAX:
-			Optional<ApplesoftKeyword> opt = ApplesoftKeyword.find(text);
-			if (opt.isPresent()) {
-				os.write(opt.get().code);
-			} else {
-				os.write(text.getBytes());
-			}
-			break;
-		}
-	}
-	
 	public static Token eol(int line) {
 		return new Token(line, Type.EOL, null, null, null);
 	}

src/main/java/com/webcodepro/applecommander/util/applesoft/Visitor.java

@@ -0,0 +1,21 @@
+package com.webcodepro.applecommander.util.applesoft;
+
+/**
+ * The Visitor interface allows some flexibility in what can be done with the
+ * AppleSoft BASIC program code.
+ *  
+ * @author rob
+ * @see Visitors
+ */
+public interface Visitor {
+	default public void visit(Program program) {
+		program.lines.forEach(l -> l.accept(this));
+	}
+	default public void visit(Line line) {
+		line.statements.forEach(s -> s.accept(this));
+	}
+	default public void visit(Statement statement) {
+		statement.tokens.forEach(t -> t.accept(this));
+	}
+	public void visit(Token token);
+}

src/main/java/com/webcodepro/applecommander/util/applesoft/Visitors.java

@@ -0,0 +1,263 @@
+package com.webcodepro.applecommander.util.applesoft;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.PrintStream;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.Stack;
+import java.util.function.Function;
+
+/**
+ * This class presents all of the common Visitor implementations via builder patterns.
+ * The number is currently small enough that all the builders and visitors are defined 
+ * in this one class.
+ *  
+ * @author rob
+ */
+public class Visitors {
+	public static PrintBuilder printBuilder() {
+		return new PrintBuilder();
+	}
+	public static class PrintBuilder {
+		private PrintStream printStream = System.out;
+		private Function<PrintBuilder,Visitor> creator = PrintVisitor::new;
+		
+		public PrintBuilder printStream(PrintStream printStream) {
+			Objects.requireNonNull(printStream);
+			this.printStream = printStream;
+			return this;
+		}
+		public PrintBuilder prettyPrint(boolean flag) {
+			creator = flag ? PrettyPrintVisitor::new : PrintVisitor::new;
+			return this;
+		}
+		public PrintBuilder prettyPrint() {
+			creator = PrettyPrintVisitor::new;
+			return this;
+		}
+		public PrintBuilder print() {
+			creator = PrintVisitor::new;
+			return this;
+		}
+		
+		public Visitor build() {
+			return creator.apply(this);
+		}
+	}
+	
+	public static ByteVisitor byteVisitor(int address) {
+		return new ByteVisitor(address);
+	}
+
+	private static class PrettyPrintVisitor implements Visitor {
+		private PrintStream printStream;
+		
+		private PrettyPrintVisitor(PrintBuilder builder) {
+			this.printStream = builder.printStream;
+		}
+		
+		@Override
+		public void visit(Line line) {
+			boolean first = true;
+			for (Statement statement : line.statements) {
+				if (first) {
+					first = false;
+					printStream.printf("%5d ", line.lineNumber);
+				} else {
+					printStream.printf("%5s ", ":");
+				}
+				statement.accept(this);
+				printStream.println();
+			}
+		}
+		@Override
+		public void visit(Token token) {
+			switch (token.type) {
+			case EOL:
+				printStream.print("<EOL>");
+				break;
+			case COMMENT:
+				printStream.printf(" REM %s", token.text);
+				break;
+			case STRING:
+				printStream.printf("\"%s\"", token.text);
+				break;
+			case KEYWORD:
+				printStream.printf(" %s ", token.keyword.text);
+				break;
+			case IDENT:
+			case SYNTAX:
+				printStream.print(token.text);
+				break;
+			case NUMBER:
+				if (Math.rint(token.number) == token.number) {
+					printStream.print(token.number.intValue());
+				} else {
+					printStream.print(token.number);
+				}
+				break;
+			}
+		}
+	}
+	
+	private static class PrintVisitor implements Visitor {
+		private PrintStream printStream;
+		
+		private PrintVisitor(PrintBuilder builder) {
+			this.printStream = builder.printStream;
+		}
+		
+		@Override
+		public void visit(Line line) {
+			printStream.printf("%d ", line.lineNumber);
+			boolean first = true;
+			for (Statement statement : line.statements) {
+				if (first) {
+					first = false;
+				} else {
+					printStream.printf(":");
+				}
+				statement.accept(this);
+			}
+			printStream.println();
+		}
+		@Override
+		public void visit(Token token) {
+			switch (token.type) {
+			case EOL:
+				printStream.print("<EOL>");
+				break;
+			case COMMENT:
+				printStream.printf("REM %s", token.text);
+				break;
+			case STRING:
+				printStream.printf("\"%s\"", token.text);
+				break;
+			case KEYWORD:
+				printStream.printf(" %s ", token.keyword.text);
+				break;
+			case IDENT:
+			case SYNTAX:
+				printStream.print(token.text);
+				break;
+			case NUMBER:
+				if (Math.rint(token.number) == token.number) {
+					printStream.print(token.number.intValue());
+				} else {
+					printStream.print(token.number);
+				}
+				break;
+			}
+		}
+	}
+	
+	public static class ByteVisitor implements Visitor {
+		private Stack<ByteArrayOutputStream> stack;
+		private int address;
+		
+		private ByteVisitor(int address) {
+			this.address = address;
+			this.stack = new Stack<>();
+		}
+		
+		/** A convenience method to invoke {@link Program#accept(Visitor)} and {@link #getBytes()}. */
+		public byte[] dump(Program program) {
+			program.accept(this);
+			return getBytes();
+		}
+		
+		public byte[] getBytes() {
+			if (stack.size() != 1) {
+				throw new RuntimeException("Error in processing internal BASIC model!");
+			}
+			return stack.peek().toByteArray();
+		}
+		
+		@Override
+		public void visit(Program program) {
+			if (stack.size() != 0) {
+				throw new RuntimeException("Please do not reuse this ByteVisitor as that is an unsafe operation.");
+			}
+			stack.push(new ByteArrayOutputStream());
+			program.lines.forEach(line -> line.accept(this));
+			ByteArrayOutputStream os = stack.peek();
+			os.write(0x00);
+			os.write(0x00);
+		}
+		
+		@Override
+		public void visit(Line line) {
+			try {
+				stack.push(new ByteArrayOutputStream());
+				boolean first = true;
+				for (Statement statement : line.statements) {
+					if (!first) {
+						first = false;
+						stack.peek().write(':');
+					}
+					statement.accept(this);
+				}
+				
+				byte[] content = stack.pop().toByteArray();
+				int nextAddress = address + content.length + 5;
+				ByteArrayOutputStream os = stack.peek();
+				os.write(nextAddress);
+				os.write(nextAddress >> 8);
+				os.write(line.lineNumber);
+				os.write(line.lineNumber >> 8);
+				os.write(content);
+				os.write(0x00);
+				this.address = nextAddress;
+			} catch (IOException ex) {
+				// Hiding the IOException as ByteArrayOutputStream does not throw it
+				throw new RuntimeException(ex);
+			}
+		}
+
+		@Override
+		public void visit(Token token) {
+			try {
+				ByteArrayOutputStream os = stack.peek();
+				switch (token.type) {
+				case COMMENT:
+					os.write(ApplesoftKeyword.REM.code);
+					os.write(token.text.getBytes());
+					break;
+				case EOL:
+					os.write(0x00);
+					break;
+				case IDENT:
+					os.write(token.text.getBytes());
+					break;
+				case KEYWORD:
+					os.write(token.keyword.code);
+					break;
+				case NUMBER:
+					if (Math.rint(token.number) == token.number) {
+						os.write(Integer.toString(token.number.intValue()).getBytes());
+					} else {
+						os.write(Double.toString(token.number).getBytes());
+					}
+					break;
+				case STRING:
+					os.write('"');
+					os.write(token.text.getBytes());
+					os.write('"');
+					break;
+				case SYNTAX:
+					Optional<ApplesoftKeyword> opt = ApplesoftKeyword.find(token.text);
+					if (opt.isPresent()) {
+						os.write(opt.get().code);
+					} else {
+						os.write(token.text.getBytes());
+					}
+					break;
+				}
+			} catch (IOException ex) {
+				// Hiding the IOException as ByteArrayOutputStream does not throw it
+				throw new RuntimeException(ex);
+			}
+		}
+	}
+}

src/main/java/io/github/applecommander/bastokenizer/Main.java

@@ -11,6 +11,7 @@ import com.webcodepro.applecommander.util.applesoft.Parser;
 import com.webcodepro.applecommander.util.applesoft.Program;
 import com.webcodepro.applecommander.util.applesoft.Token;
 import com.webcodepro.applecommander.util.applesoft.TokenReader;
+import com.webcodepro.applecommander.util.applesoft.Visitors;
 
 import picocli.CommandLine;
 import picocli.CommandLine.Command;
@@ -43,6 +44,9 @@ public class Main implements Callable<Void> {
 	@Option(names = "--pretty", description = "Pretty print structure as bastokenizer understands it.")
 	private boolean prettyPrint;
 
+	@Option(names = "--list", description = "List structure as bastokenizer understands it.")
+	private boolean listPrint;
+
 	@Option(names = "--tokens", description = "Dump token list to stdout for debugging.")
 	private boolean showTokens;
 
@@ -64,10 +68,10 @@ public class Main implements Callable<Void> {
 	
 	/** A basic test to ensure parameters are somewhat sane. */
 	public boolean checkParameters() {
-		if (pipeOutput && (hexFormat || copyFormat || prettyPrint || showTokens)) {
+		if (pipeOutput && (hexFormat || copyFormat || prettyPrint || listPrint || showTokens)) {
 			System.err.println("The pipe option blocks any other stdout options.");
 			return false;
-		} else if (!(pipeOutput || hexFormat || copyFormat || prettyPrint || showTokens || outputFile != null)) {
+		} else if (!(pipeOutput || hexFormat || copyFormat || prettyPrint || listPrint || showTokens || outputFile != null)) {
 			System.err.println("What do you want to do?");
 			return false;
 		}
@@ -82,11 +86,11 @@ public class Main implements Callable<Void> {
 		}
 		Parser parser = new Parser(tokens);
 		Program program = parser.parse();
-		if (prettyPrint) {
-			program.prettyPrint(System.out);
+		if (prettyPrint || listPrint) {
+			program.accept(Visitors.printBuilder().prettyPrint(prettyPrint).build());
 		}
 
-		byte[] data = program.toBytes(address);
+		byte[] data = Visitors.byteVisitor(address).dump(program);
 		if (hexFormat) {
 			hexDump(address, data, false);
 		}