Two changes: (1) Refactored "proofreaders" into an input buffer-based proofreader and a tokenized proofreader along with code changes; (2) Checkit now handles "?" as "PRINT".

api/src/main/java/org/applecommander/bastools/api/proofreaders/ApplesoftInputBufferProofReader.java

@@ -0,0 +1,35 @@
+package org.applecommander.bastools.api.proofreaders;
+
+import org.applecommander.bastools.api.Configuration;
+import org.applecommander.bastools.api.Visitor;
+import org.applecommander.bastools.api.Visitors;
+import org.applecommander.bastools.api.model.Program;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+
+/**
+ * Standard interface for proofreaders that are evaluated as code is typed in.
+ * That is, these evaluate the input buffer at $200 when a return is issued.
+ */
+public interface ApplesoftInputBufferProofReader {
+    /**
+     * Returns the configuration object to use. The configuration object includes the following details:
+     * start address, number preservation settings, and file name.
+     */
+    Configuration getConfiguration();
+    /** Adds program by converting to text and using addProgramText. */
+    default void addProgram(Program program) {
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        PrintStream printStream = new PrintStream(outputStream);
+        Visitor printVisitor = Visitors.printBuilder(getConfiguration()).printStream(printStream).print().build();
+        printVisitor.visit(program);
+        addProgramText(outputStream.toString());
+    }
+    /** Adds source code line-by-line using addLine. */
+    default void addProgramText(String code) {
+        code.lines().forEach(this::addLine);
+    }
+    /** Parses the line and adds to the current checksums. */
+    void addLine(String line);
+}

api/src/main/java/org/applecommander/bastools/api/proofreaders/ApplesoftTokenizedProofReader.java

@@ -0,0 +1,24 @@
+package org.applecommander.bastools.api.proofreaders;
+
+import org.applecommander.bastools.api.Configuration;
+import org.applecommander.bastools.api.model.Program;
+import org.applecommander.bastools.api.visitors.ByteVisitor;
+
+/**
+ * Standard interface for proofreaders that evaluate a tokenized program.
+ */
+public interface ApplesoftTokenizedProofReader {
+    /**
+     * Returns the configuration object to use. The configuration object includes the following details:
+     * start address, number preservation settings, and file name.
+     */
+    Configuration getConfiguration();
+    /** Convert the Program to a tokenized byte[] and then process with proofreader. */
+    default void addProgram(Program program) {
+        ByteVisitor byteVisitor = new ByteVisitor(getConfiguration());
+        byteVisitor.visit(program);
+        addBytes(byteVisitor.getBytes());
+    }
+    /** Parses the line and adds to the current checksums. */
+    void addBytes(byte... tokenizedProgram);
+}

api/src/main/java/org/applecommander/bastools/api/proofreaders/ComputeAutomaticProofreader.java

@@ -1,34 +1,43 @@
 package org.applecommander.bastools.api.proofreaders;
 
 import org.applecommander.bastools.api.Configuration;
-import org.applecommander.bastools.api.model.Line;
 import org.applecommander.bastools.api.model.Program;
 
-public class ComputeAutomaticProofreader extends LineOrientedProofReader {
+public class ComputeAutomaticProofreader implements ApplesoftInputBufferProofReader {
+    private final Configuration config;
+    private final Checksum checksum = new Checksum();
+
     public ComputeAutomaticProofreader(Configuration config) {
-        super(config);
+        this.config = config;
     }
 
     @Override
-    public Program visit(Program program) {
+    public Configuration getConfiguration() {
+        return config;
+    }
+
+    @Override
+    public void addProgram(Program program) {
         System.out.println("Compute! Apple Automatic Proofreader, Copyright 1985");
-        return super.visit(program);
+        ApplesoftInputBufferProofReader.super.addProgram(program);
     }
 
     @Override
-    public Line visit(Line line) {
-        String text = toString(line);
-
-        int checksum = 0;
-        for (int i=text.length()-1; i>=0; i--) {
-            char ch = text.charAt(i);
+    public void addLine(String line) {
+        checksum.reset();
+        for (int i=line.length()-1; i>=0; i--) {
+            char ch = line.charAt(i);
             if (ch != ' ') {
-                checksum = proofreader(checksum, ch|0x80);
+                checksum.add(ch|0x80);
             }
         }
 
-        System.out.printf("%02X | %s\n", checksum, text);
-        return line;
+        System.out.printf("%02X | %s\n", checksum.value(), line);
+    }
+
+    // For testing purposes; only valid for the line
+    protected int getChecksumValue() {
+        return checksum.value();
     }
 
     /**
@@ -43,20 +52,34 @@ public class ComputeAutomaticProofreader extends LineOrientedProofReader {
      * </pre>
      * Generalized algorithm: <code>cksum = (cksum << 1) + (char|$80) + carry</code>
      */
-    public static int proofreader(int checksum, int value) {
-        assert value >= 0 && value <= 0xff;
-        checksum <<= 1;
-        // Handle carry from ASL
-        if (checksum > 0xff) {
-            checksum++;
-            checksum &= 0xff;
+    public static class Checksum implements ProofReaderChecksum {
+        private int checksum = 0;
+
+        @Override
+        public void reset() {
+            this.checksum = 0;
         }
-        // Handle carry from first ADC
-        checksum += value;
-        if (checksum > 0xff) {
-            checksum++;
-            checksum &= 0xff;
+
+        @Override
+        public void add(int value) {
+            assert value >= 0 && value <= 0xff;
+            checksum <<= 1;
+            // Handle carry from ASL
+            if (checksum > 0xff) {
+                checksum++;
+                checksum &= 0xff;
+            }
+            // Handle carry from first ADC
+            checksum += value;
+            if (checksum > 0xff) {
+                checksum++;
+                checksum &= 0xff;
+            }
+        }
+
+        @Override
+        public int value() {
+            return checksum;
         }
-        return checksum;
     }
 }

api/src/main/java/org/applecommander/bastools/api/proofreaders/LineOrientedProofReader.java

@@ -1,58 +0,0 @@
-package org.applecommander.bastools.api.proofreaders;
-
-import org.applecommander.bastools.api.Configuration;
-import org.applecommander.bastools.api.Visitor;
-import org.applecommander.bastools.api.model.Line;
-import org.applecommander.bastools.api.model.Statement;
-import org.applecommander.bastools.api.model.Token;
-
-import java.io.PrintWriter;
-import java.io.StringWriter;
-
-public abstract class LineOrientedProofReader implements Visitor {
-    protected final Configuration config;
-
-    protected LineOrientedProofReader(Configuration config) {
-        this.config = config;
-    }
-
-    public String toString(Line line) {
-        StringWriter sw = new StringWriter();
-        PrintWriter pw = new PrintWriter(sw);
-        pw.printf("%d ", line.lineNumber);
-        boolean first = true;
-        for (Statement statement : line.statements) {
-            if (first) {
-                first = false;
-            } else {
-                pw.print(":");
-            }
-            for (Token token : statement.tokens) {
-                switch (token.type()) {
-                    case EOL:
-                        pw.print("<EOL>");
-                        break;
-                    case COMMENT:
-                        pw.printf("REM %s", token.text());
-                        break;
-                    case DATA, IDENT, SYNTAX:
-                        pw.print(token.text());
-                        break;
-                    case STRING:
-                        pw.printf("\"%s\"", token.text());
-                        break;
-                    case KEYWORD:
-                        pw.printf(" %s ", token.keyword().text);
-                        break;
-                    case DIRECTIVE:
-                        pw.printf("%s ", token.text());
-                        break;
-                    case NUMBER:
-                        pw.print(config.numberToString(token));
-                        break;
-                }
-            }
-        }
-        return sw.toString();
-    }
-}

api/src/main/java/org/applecommander/bastools/api/proofreaders/MicrosparcKeyPerfect2.java

@@ -1,9 +1,6 @@
 package org.applecommander.bastools.api.proofreaders;
 
 import org.applecommander.bastools.api.Configuration;
-import org.applecommander.bastools.api.Visitor;
-import org.applecommander.bastools.api.model.Program;
-import org.applecommander.bastools.api.visitors.ByteVisitor;
 
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
@@ -44,19 +41,21 @@ import java.util.List;
  * 1710-   60          RTS
  * </pre>
  */
-public class MicrosparcKeyPerfect2 implements Visitor {
+public class MicrosparcKeyPerfect2 implements ApplesoftTokenizedProofReader {
     private final Configuration config;
-    private final ByteVisitor byteVisitor;
 
     public MicrosparcKeyPerfect2(Configuration config) {
         this.config = config;
-        this.byteVisitor = new ByteVisitor(config);
     }
 
     @Override
-    public Program visit(Program program) {
-        byteVisitor.visit(program);
-        ByteBuffer code = ByteBuffer.wrap(byteVisitor.getBytes());
+    public Configuration getConfiguration() {
+        return config;
+    }
+
+    @Override
+    public void addBytes(byte... tokenizedProgram) {
+        ByteBuffer code = ByteBuffer.wrap(tokenizedProgram);
         code.order(ByteOrder.LITTLE_ENDIAN);
 
         System.out.println("Line# - Line#   CODE-2.0");
@@ -96,8 +95,6 @@ public class MicrosparcKeyPerfect2 implements Visitor {
             printLines(lines, lineChecksum);
         }
         printLine("PROGRAM TOTAL", programChecksum);
-
-        return program;
     }
 
     public void printLines(List<Integer> lines, int lineChecksum) {

api/src/main/java/org/applecommander/bastools/api/proofreaders/MicrosparcKeyPerfect4.java

@@ -1,9 +1,6 @@
 package org.applecommander.bastools.api.proofreaders;
 
 import org.applecommander.bastools.api.Configuration;
-import org.applecommander.bastools.api.Visitor;
-import org.applecommander.bastools.api.model.Program;
-import org.applecommander.bastools.api.visitors.ByteVisitor;
 
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
@@ -85,19 +82,21 @@ import java.util.List;
  * </pre>
  * ('@' replaced with ']' since Javadoc uses '@' for other purposes.)
  */
-public class MicrosparcKeyPerfect4 implements Visitor {
+public class MicrosparcKeyPerfect4 implements ApplesoftTokenizedProofReader {
     private final Configuration config;
-    private final ByteVisitor byteVisitor;
 
     public MicrosparcKeyPerfect4(Configuration config) {
         this.config = config;
-        this.byteVisitor = new ByteVisitor(config);
     }
 
     @Override
-    public Program visit(Program program) {
-        byteVisitor.visit(program);
-        ByteBuffer code = ByteBuffer.wrap(byteVisitor.getBytes());
+    public Configuration getConfiguration() {
+        return config;
+    }
+
+    @Override
+    public void addBytes(byte... tokenizedProgram) {
+        ByteBuffer code = ByteBuffer.wrap(tokenizedProgram);
         code.order(ByteOrder.LITTLE_ENDIAN);
 
         System.out.println("Line# - Line#   CODE-4.0");
@@ -112,9 +111,9 @@ public class MicrosparcKeyPerfect4 implements Visitor {
             if (ptr == 0) break;
             // Line number always gets added to checksum and total
             int b1 = Byte.toUnsignedInt(code.get());
-            checksum.addByte(b1);
+            checksum.add(b1);
             int b2 = Byte.toUnsignedInt(code.get());
-            checksum.addByte(b2);
+            checksum.add(b2);
             programChecksum+= 2;
             lines.add(b2 << 8 | b1);
             // Process tokenized line...
@@ -123,7 +122,7 @@ public class MicrosparcKeyPerfect4 implements Visitor {
                 ch = Byte.toUnsignedInt(code.get());
                 if (ch > 0x20 || ch == 0x04) {
                     programChecksum++;
-                    checksum.addByte(ch);
+                    checksum.add(ch);
                 }
             } while (ch > 0);
 
@@ -137,15 +136,13 @@ public class MicrosparcKeyPerfect4 implements Visitor {
             printLines(lines, checksum);
         }
         printLine("PROGRAM TOTAL", programChecksum);
-
-        return program;
     }
 
     public void printLines(List<Integer> lines, Checksum checksum) {
         int firstLine = lines.getFirst();
         int lastLine = lines.getLast();
         String text = String.format("%5d - %5d", firstLine, lastLine);
-        printLine(text, checksum.getChecksum());
+        printLine(text, checksum.value());
     }
 
     public static void printLine(String text, int checksum) {
@@ -161,20 +158,23 @@ public class MicrosparcKeyPerfect4 implements Visitor {
         System.out.println();
     }
 
-    public static class Checksum {
+    public static class Checksum implements ProofReaderChecksum {
         private int lineChecksum = 0;       // low byte with has EOR, ROL, ADC
         private int lineCounter = 0;        // high 2 bytes that just ADC on carry
 
-        public int getChecksum() {
+        @Override
+        public int value() {
             return lineCounter << 8 | lineChecksum;
         }
 
+        @Override
         public void reset() {
             lineChecksum = 0;
             lineCounter = 0;
         }
 
-        public void addByte(int code) {
+        @Override
+        public void add(int code) {
             int acc = lineChecksum ^ code;
             acc <<= 1;
             if (acc > 0xff) {

api/src/main/java/org/applecommander/bastools/api/proofreaders/MicrosparcKeyPerfect5.java

@@ -1,11 +1,7 @@
 package org.applecommander.bastools.api.proofreaders;
 
 import org.applecommander.bastools.api.Configuration;
-import org.applecommander.bastools.api.Visitor;
-import org.applecommander.bastools.api.model.Program;
-import org.applecommander.bastools.api.visitors.ByteVisitor;
 
-import javax.swing.*;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.util.ArrayList;
@@ -110,19 +106,21 @@ import java.util.List;
  * </pre>
  * ('@' replaced with ']' since Javadoc uses '@' for other purposes.)
  */
-public class MicrosparcKeyPerfect5 implements Visitor {
+public class MicrosparcKeyPerfect5 implements ApplesoftTokenizedProofReader {
     private final Configuration config;
-    private final ByteVisitor byteVisitor;
 
     public MicrosparcKeyPerfect5(Configuration config) {
         this.config = config;
-        this.byteVisitor = new ByteVisitor(config);
     }
 
     @Override
-    public Program visit(Program program) {
-        byteVisitor.visit(program);
-        ByteBuffer code = ByteBuffer.wrap(byteVisitor.getBytes());
+    public Configuration getConfiguration() {
+        return config;
+    }
+
+    @Override
+    public void addBytes(byte... tokenizedProgram) {
+        ByteBuffer code = ByteBuffer.wrap(tokenizedProgram);
         code.order(ByteOrder.LITTLE_ENDIAN);
 
         System.out.println("Line# - Line#   CODE-5.0");
@@ -136,11 +134,11 @@ public class MicrosparcKeyPerfect5 implements Visitor {
             if (ptr == 0) break;
             // Line number always gets added to checksum and total
             int b1 = Byte.toUnsignedInt(code.get());
-            lineChecksum.addByte(b1);
-            pgmChecksum.addByte(b1);
+            lineChecksum.add(b1);
+            pgmChecksum.add(b1);
             int b2 = Byte.toUnsignedInt(code.get());
-            lineChecksum.addByte(b2);
-            pgmChecksum.addByte(b2);
+            lineChecksum.add(b2);
+            pgmChecksum.add(b2);
             lines.add(b2 << 8 | b1);
             // Process tokenized line...
             boolean inComment = false;
@@ -149,8 +147,8 @@ public class MicrosparcKeyPerfect5 implements Visitor {
                 ch = Byte.toUnsignedInt(code.get());
                 if (ch == 0xb2) {
                     inComment = true;
-                    lineChecksum.addByte(ch);
-                    pgmChecksum.addByte(ch);
+                    lineChecksum.add(ch);
+                    pgmChecksum.add(ch);
                 }
                 else if (inComment) {
                     // do not add to checksum
@@ -159,8 +157,8 @@ public class MicrosparcKeyPerfect5 implements Visitor {
                     if (ch >= 0x60 && ch < 0x80) {
                         ch -= 0x20;     // Force characters to uppercase
                     }
-                    lineChecksum.addByte(ch);
-                    pgmChecksum.addByte(ch);
+                    lineChecksum.add(ch);
+                    pgmChecksum.add(ch);
                 }
             } while (ch > 0);
 
@@ -174,8 +172,6 @@ public class MicrosparcKeyPerfect5 implements Visitor {
             printLines(lines, lineChecksum);
         }
         printLine("PROGRAM TOTAL", pgmChecksum);
-
-        return program;
     }
 
     public void printLines(List<Integer> lines, Checksum checksum) {
@@ -186,24 +182,27 @@ public class MicrosparcKeyPerfect5 implements Visitor {
     }
 
     public static void printLine(String text, Checksum checksum) {
-        System.out.printf("%-13.13s   %08X\n", text, checksum.getChecksum());
+        System.out.printf("%-13.13s   %08X\n", text, checksum.value());
     }
 
-    public static class Checksum {
+    public static class Checksum implements ProofReaderChecksum {
         /**
          * Checksum is 4 bytes, long is 8 so we don't get surprised by negativity.
          */
         private long checksum = 0xffffffffL;
 
-        public int getChecksum() {
+        @Override
+        public int value() {
             return (int)checksum;
         }
 
+        @Override
         public void reset() {
             checksum = 0xffffffffL;
         }
 
-        public void addByte(int code) {
+        @Override
+        public void add(int code) {
             assert code >= 0 && code <= 0xff;
             // Combines the CHKSUM_V5_1 effort
             int idx = (int)(checksum >> 24 & 0xff) ^ code;

api/src/main/java/org/applecommander/bastools/api/proofreaders/NibbleAppleChecker.java

@@ -1,70 +1,64 @@
 package org.applecommander.bastools.api.proofreaders;
 
 import org.applecommander.bastools.api.Configuration;
-import org.applecommander.bastools.api.Visitor;
 import org.applecommander.bastools.api.model.Program;
-import org.applecommander.bastools.api.visitors.ByteVisitor;
 
-public class NibbleAppleChecker implements Visitor {
+public class NibbleAppleChecker implements ApplesoftTokenizedProofReader {
     private final Configuration config;
-    private final ByteVisitor byteVisitor;
+    private int length;
+    private final Checksum checksum = new Checksum();
 
     public NibbleAppleChecker(Configuration config) {
         this.config = config;
-        this.byteVisitor = new ByteVisitor(config);
     }
 
     @Override
-    public Program visit(Program program) {
-        byteVisitor.visit(program);
-        byte[] code = byteVisitor.getBytes();
-        Checksum checksum = new Checksum();
-        checksum.compute(code, config.startAddress);
+    public Configuration getConfiguration() {
+        return config;
+    }
+
+    @Override
+    public void addProgram(Program program) {
+        ApplesoftTokenizedProofReader.super.addProgram(program);
 
         System.out.printf("On: %s\n", config.sourceFile.getName());
         System.out.println("Type: A");
         System.out.println();
-        System.out.printf("Length: %04X\n", checksum.getLength());
-        System.out.printf("Checksum: %02X\n", checksum.getChecksum());
-        return program;
+        System.out.printf("Length: %04X\n", length);
+        System.out.printf("Checksum: %02X\n", checksum.value());
     }
 
-    public static class Checksum {
-        private int length;
-        private int checksum;
-
-        public int getLength() {
-            return length;
+    @Override
+    public void addBytes(byte... tokenizedProgram) {
+        // Length is less 2 for Applesoft
+        length = tokenizedProgram.length+1 - 2;
+        // Zero out the next line links
+        int nextAddr = config.startAddress;
+        while (nextAddr >= 0 && nextAddr < tokenizedProgram.length) {
+            nextAddr = (tokenizedProgram[nextAddr+1]<<8 | tokenizedProgram[nextAddr]) - config.startAddress;
+            tokenizedProgram[nextAddr] = 0;
+            tokenizedProgram[nextAddr+1] = 0;
         }
-        public int getChecksum() {
-            return checksum;
-        }
-
-        public void compute(byte[] code, int startAddress) {
-            // Length is less 2 for Applesoft
-            length = code.length+1 - 2;
-            // Zero out the next line links
-            int nextAddr = startAddress;
-            while (nextAddr >= 0 && nextAddr < code.length) {
-                nextAddr = (code[nextAddr+1]<<8 | code[nextAddr]) - startAddress;
-                code[nextAddr] = 0;
-                code[nextAddr+1] = 0;
-            }
-            // Compute checksum
-            this.checksum = 0;
-            for (int i=0; i<code.length; i++) {
-                int acc = Byte.toUnsignedInt(code[i]);
-                if (acc >= 0x21 || acc == 0x04) {
-                    this.checksum = checksum(this.checksum, acc);
-                }
-                else {
-                    // We skip _and_ reduce the length by 1
-                    this.length--;
-                }
+        // Compute checksum
+        checksum.reset();
+        for (byte b : tokenizedProgram) {
+            int acc = Byte.toUnsignedInt(b);
+            if (acc >= 0x21 || acc == 0x04) {
+                checksum.add(acc);
+            } else {
+                // We skip _and_ reduce the length by 1
+                this.length--;
             }
         }
     }
 
+    public int getLength() {
+        return length;
+    }
+    public int getChecksumValue() {
+        return checksum.value();
+    }
+
     /**
      * Compute a single iteration of the checksum. Broken out for testing purposes.
      * <pre>
@@ -76,23 +70,38 @@ public class NibbleAppleChecker implements Visitor {
      *        STA CKCD
      * </pre>
      */
-    public static int checksum(int checksum, int acc) {
-        // EOR CKCD
-        acc ^= checksum;
-        // ROL A
-        acc <<= 1;
-        // ADC CKCD
-        if (acc >= 0xff) {
-            checksum++;
-            acc &= 0xff;
+    public static class Checksum implements ProofReaderChecksum {
+        private int checksum;
+
+        @Override
+        public void reset() {
+            this.checksum = 0;
         }
-        acc += checksum;
-        // ADC #0
-        if (acc > 0xff) {
-            acc++;
-            acc &= 0xff;
+
+        @Override
+        public void add(int acc) {
+            // EOR CKCD
+            acc ^= checksum;
+            // ROL A
+            acc <<= 1;
+            // ADC CKCD
+            if (acc >= 0xff) {
+                checksum++;
+                acc &= 0xff;
+            }
+            acc += checksum;
+            // ADC #0
+            if (acc > 0xff) {
+                acc++;
+                acc &= 0xff;
+            }
+            // STA CKCD
+            checksum = acc;
+        }
+
+        @Override
+        public int value() {
+            return this.checksum;
         }
-        // STA CKCD
-        return acc;
     }
 }

api/src/main/java/org/applecommander/bastools/api/proofreaders/NibbleCheckit.java

@@ -1,76 +1,72 @@
 package org.applecommander.bastools.api.proofreaders;
 
 import org.applecommander.bastools.api.Configuration;
-import org.applecommander.bastools.api.model.Line;
-import org.applecommander.bastools.api.model.Program;
-import org.applecommander.bastools.api.model.Statement;
-import org.applecommander.bastools.api.model.Token;
 
-public class NibbleCheckit extends LineOrientedProofReader {
-    private int totalChecksum;
-    private int lineChecksum;
+public class NibbleCheckit implements ApplesoftInputBufferProofReader {
+    private final Configuration config;
+    private final Checksum totalChecksum = new Checksum();
+    private final Checksum lineChecksum = new Checksum();
 
     public NibbleCheckit(Configuration config) {
-        super(config);
+        this.config = config;
     }
 
     @Override
-    public Program visit(Program program) {
+    public Configuration getConfiguration() {
+        return config;
+    }
+
+    /** {@inheritDoc} */
+    @Override
+    public void addProgramText(String code) {
         System.out.println("Nibble Checkit, Copyright 1988, Microsparc Inc.");
-        try {
-            return super.visit(program);
-        } finally {
-            System.out.printf("TOTAL: %02X%02X\n", totalChecksum & 0xff, totalChecksum >> 8);
-        }
+        ApplesoftInputBufferProofReader.super.addProgramText(code);
+        System.out.printf("TOTAL: %02X%02X\n", totalChecksum.checksum & 0xff, totalChecksum.checksum >> 8);
     }
 
+    /** {@inheritDoc} */
     @Override
-    public Line visit(Line line) {
+    public void addLine(String line) {
         // Calculate and output line value
-        lineChecksum = 0;
-        for (char ch : Integer.toString(line.lineNumber).toCharArray()) {
-            lineChecksum = checkit(lineChecksum, ch|0x80);
-        }
-        boolean first = true;
-        for (Statement statement : line.statements) {
-            if (!first) {
-                // We need to synthesize the colons
-                lineChecksum = checkit(lineChecksum, ':'|0x80);
-            }
-            super.visit(statement);
-            first = false;
-        }
-        int cs = ( (lineChecksum & 0xff) - (lineChecksum >> 8) ) & 0xff;
-        System.out.printf("%02X | %s\n", cs, toString(line));
+        lineChecksum.reset();
 
-        // Update program values
-        totalChecksum = checkit(totalChecksum, line.lineNumber & 0xff);
-        totalChecksum = checkit(totalChecksum, line.lineNumber >> 8);
-        return line;
-    }
+        // The ? => PRINT replacement always occurs, including in strings!
+        line = line.replace("?", "PRINT");
 
-    @Override
-    public Token visit(Token token) {
-        String value = switch (token.type()) {
-            case EOL, DIRECTIVE -> "";
-            case DATA, SYNTAX, IDENT -> token.text();
-            case COMMENT -> "REM";
-            case KEYWORD -> token.keyword().text;
-            case NUMBER -> {
-                if (token.text() != null) {
-                    yield token.text();
-                }
-                yield config.numberToString(token);
-            }
-            case STRING -> String.format("\"%s\"", token.text());
-        };
         boolean inQuote = false;
-        for (char ch : value.toCharArray()) {
+        StringBuilder remLettersSeen = new StringBuilder();
+        for (char ch : line.toCharArray()) {
             if (ch == '"') inQuote = !inQuote;
             if (!inQuote && ch == ' ') continue;
-            lineChecksum = checkit(lineChecksum, ch|0x80);
+            lineChecksum.add(ch|0x80);
+
+            // we only allow R E M from a comment; skip rest of the comment
+            remLettersSeen.append(ch);
+            if ("REM".contentEquals(remLettersSeen)) {
+                break;
+            }
+            else if ("R".contentEquals(remLettersSeen) || "RE".contentEquals(remLettersSeen)) {
+                // Keep them, this may be a comment
+            }
+            else {
+                remLettersSeen = new StringBuilder();
+            }
         }
-        return token;
+
+        int cs = ( (lineChecksum.checksum & 0xff) - (lineChecksum.checksum >> 8) ) & 0xff;
+        System.out.printf("%02X | %s\n", cs, line);
+
+        // Update program values
+        int lineNumber = Integer.parseInt(line.split(" ")[0].trim());
+        totalChecksum.add(lineNumber & 0xff);
+        totalChecksum.add(lineNumber >> 8);
+    }
+
+    public int getLineChecksumValue() {
+        return lineChecksum.value();
+    }
+    public int getTotalChecksumValue() {
+        return totalChecksum.value();
     }
 
     /**
@@ -101,17 +97,29 @@ public class NibbleCheckit extends LineOrientedProofReader {
      * XOR. The result is the middle two bytes where the checksum resides. (Note that the
      * <code>0x1021</code> was shifted by a byte as well.)
      */
-    public static int checkit(int checksum, int value) {
-        assert value >= 0 && value <= 0xff;
-        int work = (checksum << 8) | value;
-        for (int i=0; i<8; i++) {
-            work <<= 1;
-            // Note: If we run into negative issues somehow, this could also be "((work & 0xff000000) != 0)".
-            if (work > 0xffffff) {
-                work &= 0xffffff;
-                work ^= 0x102100;
+    public static class Checksum implements ProofReaderChecksum {
+        private int checksum = 0;
+        @Override
+        public void reset() {
+            this.checksum = 0;
+        }
+        @Override
+        public void add(int value) {
+            assert value >= 0 && value <= 0xff;
+            int work = (checksum << 8) | value;
+            for (int i=0; i<8; i++) {
+                work <<= 1;
+                // Note: If we run into negative issues somehow, this could also be "((work & 0xff000000) != 0)".
+                if (work > 0xffffff) {
+                    work &= 0xffffff;
+                    work ^= 0x102100;
+                }
             }
+            checksum = work >> 8;
+        }
+        @Override
+        public int value() {
+            return checksum;
         }
-        return work >> 8;
     }
 }

api/src/main/java/org/applecommander/bastools/api/proofreaders/ProofReaderChecksum.java

@@ -0,0 +1,10 @@
+package org.applecommander.bastools.api.proofreaders;
+
+public interface ProofReaderChecksum {
+    /** Reset the checksum back to initial state. */
+    void reset();
+    /** Add a value (typically a byte) into the checksum. */
+    void add(int value);
+    /** Get the current value of the checksum. */
+    int value();
+}

api/src/test/java/org/applecommander/bastools/api/ClassicTokenReaderTest.java

@@ -12,7 +12,7 @@ import java.util.List;
 import java.util.Objects;
 import java.util.Queue;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.fail;
 
 public class ClassicTokenReaderTest {
     @Test
@@ -357,6 +357,23 @@ public class ClassicTokenReaderTest {
                 .end());
     }
 
+    @Test
+    public void testQuestionMarkAsPrint49() throws IOException {
+        testCode("""
+                100  PRINT "HELLO WORLD"
+                110  PRINT "HELLO WORLD?"
+                """,
+            Tokens.builder()
+                .number("100")
+                    .keyword(ApplesoftKeyword.PRINT)
+                    .data("\"HELLO WORLD\"")
+                    .nextLine()
+                .number("110")
+                    .keyword(ApplesoftKeyword.PRINT)
+                    .data("\"HELLO WORLD?\"")
+                .end());
+    }
+
     public void testCode(String code, Token... expectedTokens) throws IOException {
         final Queue<Token> actualTokens = ClassicTokenReader.tokenize(new StringReader(code));
         final Token[] actualArray = actualTokens.toArray(new Token[0]);

api/src/test/java/org/applecommander/bastools/api/proofreaders/ComputeAutomaticProofreaderTest.java

@@ -1,7 +1,10 @@
 package org.applecommander.bastools.api.proofreaders;
 
+import org.applecommander.bastools.api.Configuration;
 import org.junit.Test;
 
+import java.io.File;
+
 import static org.junit.Assert.assertEquals;
 
 /**
@@ -17,13 +20,12 @@ public class ComputeAutomaticProofreaderTest {
     }
 
     protected int performLineCalc(String text) {
-        int checksum = 0;
-        for (int i=text.length()-1; i>=0; i--) {
-            char ch = text.charAt(i);
-            if (ch != ' ') {
-                checksum = ComputeAutomaticProofreader.proofreader(checksum, ch|0x80);
-            }
-        }
-        return checksum;
+        Configuration config = Configuration.builder()
+                .preserveNumbers(true)
+                .sourceFile(new File("test.bas"))
+                .build();
+        ComputeAutomaticProofreader proofreader = new ComputeAutomaticProofreader(config);
+        proofreader.addLine(text);
+        return proofreader.getChecksumValue();
     }
 }

api/src/test/java/org/applecommander/bastools/api/proofreaders/MicrosparcKeyPerfect4Test.java

@@ -16,8 +16,8 @@ public class MicrosparcKeyPerfect4Test {
         };
         Checksum checksum = new Checksum();
         for (int b : code) {
-            checksum.addByte(b);
+            checksum.add(b);
         }
-        assertEquals(0x783, checksum.getChecksum());
+        assertEquals(0x783, checksum.value());
     }
 }

api/src/test/java/org/applecommander/bastools/api/proofreaders/MicrosparcKeyPerfect5Test.java

@@ -16,9 +16,9 @@ public class MicrosparcKeyPerfect5Test {
         };
         Checksum checksum = new Checksum();
         for (int b : code) {
-            checksum.addByte(b);
+            checksum.add(b);
         }
-        assertEquals(0xC397EF76, checksum.getChecksum());
+        assertEquals(0xC397EF76, checksum.value());
     }
 
     @Test
@@ -28,8 +28,8 @@ public class MicrosparcKeyPerfect5Test {
         };
         Checksum checksum = new Checksum();
         for (int b : code) {
-            checksum.addByte(b);
+            checksum.add(b);
         }
-        assertEquals(0x9b714628, checksum.getChecksum());
+        assertEquals(0x9b714628, checksum.value());
     }
 }

api/src/test/java/org/applecommander/bastools/api/proofreaders/NibbleAppleCheckerTest.java

@@ -1,25 +1,36 @@
 package org.applecommander.bastools.api.proofreaders;
 
+import org.applecommander.bastools.api.Configuration;
 import org.junit.Test;
 
+import java.io.File;
+
 import static org.junit.Assert.assertEquals;
 
 public class NibbleAppleCheckerTest {
     @Test
     public void testChecksum() {
-        // Based on 6502 assembly run
-        assertEquals(0x13, NibbleAppleChecker.checksum(0x0, 0x89));     // TEXT
-        assertEquals(0x65, NibbleAppleChecker.checksum(0x13, 0x3a));    // :
-        assertEquals(0x4b, NibbleAppleChecker.checksum(0x65, 0x97));    // HOME
+        // Based on 6502 assembly run - checks step-by-step values
+        NibbleAppleChecker.Checksum checksum = new NibbleAppleChecker.Checksum();
+        checksum.add(0x89);     // TEXT
+        assertEquals(0x13, checksum.value());
+        checksum.add(0x3a);     // :
+        assertEquals(0x65, checksum.value());
+        checksum.add(0x97);     // HOME
+        assertEquals(0x4b, checksum.value());
     }
 
     @Test
     public void testCode() {
-        NibbleAppleChecker.Checksum cksum = new NibbleAppleChecker.Checksum();
+        Configuration config = Configuration.builder()
+                .startAddress(0xb01)
+                .sourceFile(new File("test.bas"))
+                .build();
+        NibbleAppleChecker checker = new NibbleAppleChecker(config);
         // 10 TEXT:HOME as a sample...
         byte[] code = { 0x09, 0x0b, 0x0a, (byte)0x89, 0x3a, (byte)0x97, 0x00, 0x00, 0x00, 0x00, 0x00 };
-        cksum.compute(code, 0xb01);
-        //assertEquals(0x2, cksum.getLength());
-        assertEquals(0x4b, cksum.getChecksum());
+        checker.addBytes(code);
+        assertEquals(0x2, checker.getLength());
+        assertEquals(0x4b, checker.getChecksumValue());
     }
 }

api/src/test/java/org/applecommander/bastools/api/proofreaders/NibbleCheckitTest.java

@@ -1,7 +1,10 @@
 package org.applecommander.bastools.api.proofreaders;
 
+import org.applecommander.bastools.api.Configuration;
 import org.junit.Test;
 
+import java.io.File;
+
 import static org.junit.Assert.assertEquals;
 
 /**
@@ -16,6 +19,12 @@ public class NibbleCheckitTest {
         assertEquals(0x91, performLineCalc("30 END"));
     }
 
+    @Test
+    public void testQuestionMark49() {
+        assertEquals(0xf6, performLineCalc("110  PRINT \"HELLO WORLD?\""));
+        assertEquals(0xe7, performLineCalc("10 PRINT \"?\""));
+    }
+
     @Test
     public void testProgramChecksum() {
         // Note: The value displayed is 1CB9, but the code prints low byte first...
@@ -23,21 +32,25 @@ public class NibbleCheckitTest {
     }
 
     protected int performLineCalc(String text) {
-        int checksum = 0;
-        for (char ch : text.toCharArray()) {
-            if (ch != ' ') {
-                checksum = NibbleCheckit.checkit(checksum, ch | 0x80);
-            }
-        }
-        return ( (checksum & 0xff) - (checksum >> 8) ) & 0xff;
+        Configuration config = Configuration.builder()
+                .preserveNumbers(true)
+                .sourceFile(new File("test.bas"))
+                .build();
+        NibbleCheckit proofreader = new NibbleCheckit(config);
+        proofreader.addLine(text);
+        return ( (proofreader.getLineChecksumValue() & 0xff) - (proofreader.getLineChecksumValue() >> 8) ) & 0xff;
     }
 
     protected int performProgramCalc(int... lineNumbers) {
-        int checksum = 0;
+        Configuration config = Configuration.builder()
+                .preserveNumbers(true)
+                .sourceFile(new File("test.bas"))
+                .build();
+        NibbleCheckit proofreader = new NibbleCheckit(config);
         for (int lineNumber : lineNumbers) {
-            checksum = NibbleCheckit.checkit(checksum, lineNumber & 0xff);
-            checksum = NibbleCheckit.checkit(checksum, lineNumber >> 8);
+            // We ignore the line, but line also computes the program checksum
+            proofreader.addLine(Integer.toString(lineNumber));
         }
-        return checksum;
+        return proofreader.getTotalChecksumValue();
     }
 }

reference/README.md

@@ -4,18 +4,19 @@
 
 Some summary notes and observations on the Apple II code checking tools.
 
-|                                | Includes REM contents | Includes spaces | Control Chars? | Case-sensitive? | Operation    | Grouping(s)                     | Size                                | Program Total                        |
-|--------------------------------|:----------------------|:----------------|:---------------|:----------------|:-------------|:--------------------------------|:------------------------------------|:-------------------------------------|
-| Compute! Automatic Proofreader | Yes                   | No              | CTRL+D         | Yes             | Input Buffer | Line                            | 1 byte                              | No                                   |
-| Nibble Checkit                 | No                    | In strings      | In Strings     | Yes             | Input Buffer | Line, Program                   | 1 byte (line)<br/>2 bytes (program) | Yes, on line numbers                 | 
-| Nibble Apple Checker           | Yes                   | No              | CTRL+D         | Yes             | Program      | Program                         | 1 byte (2 bytes length)             | Yes, checksum and length calculation |
-| MicroSPARC Key Perfect 2       | Yes                   | Yes             | All            | Yes             | Program      | Groups of 10 lines,<br/>Program | Max 3 bytes                         | Yes, byte count                      | 
-| MicroSPARC Key Perfect 4       | Yes                   | No              | CTRL+D         | Yes             | Program      | Groups of 10 lines,<br/>Program | Max 3 bytes                         | Yes, byte count                      | 
-| MicroSPARC Key Perfect 5       | No                    | No              | CTRL+D         | No              | Program      | Groups of 10 lines,<br/>Program | 4 bytes                             | Yes                                  |
+|                                | Includes REM contents | Includes spaces | Control Chars? | Other? | Case-sensitive? | Operation    | Grouping(s)                     | Checksum Size                       | Program Total                        |
+|--------------------------------|:----------------------|:----------------|:---------------|--------|:----------------|:-------------|:--------------------------------|:------------------------------------|:-------------------------------------|
+| Compute! Automatic Proofreader | Yes                   | No              | CTRL+D         | N/A    | Yes             | Input Buffer | Line                            | 1 byte                              | No                                   |
+| Nibble Checkit                 | No                    | In strings      | In Strings     | "?"    | Yes             | Input Buffer | Line, Program                   | 1 byte (line)<br/>2 bytes (program) | Yes, on line numbers                 | 
+| Nibble Apple Checker           | Yes                   | No              | CTRL+D         | N/A    | Yes             | Program      | Program                         | 1 byte (2 bytes length)             | Yes, checksum and length calculation |
+| MicroSPARC Key Perfect 2       | Yes                   | Yes             | All            | N/A    | Yes             | Program      | Groups of 10 lines,<br/>Program | Max 3 bytes                         | Yes, byte count                      | 
+| MicroSPARC Key Perfect 4       | Yes                   | No              | CTRL+D         | N/A    | Yes             | Program      | Groups of 10 lines,<br/>Program | Max 3 bytes                         | Yes, byte count                      | 
+| MicroSPARC Key Perfect 5       | No                    | No              | CTRL+D         | N/A    | No              | Program      | Groups of 10 lines,<br/>Program | 4 bytes                             | Yes                                  |
 
 * *Includes REM contents* - most checksum algorithms includes the REM as well as the contents of the REM statement; some only include the REM itself.
 * *Includes spaces* - indicates if whitespace is important.
 * *Control Chars?* - indicates if any control characters are included in the checksum.
+* *Other?* - Checkit replaces "?" with "PRINT" to standardize the shortcut for the `PRINT` statement. The catch is that it ignores quotes. So _any_ "?" is replaced with "PRINT" for the checksum algorithm. 
 * *Case-sensitive?* - is "A" and "a" handled differently?
 * *Operation* - if "Input Buffer" is specified, the checksums are displayed after a line of code has been entered; otherwise, the program must be completed and saved before running checksum.
 * *Groupings* - what, if any, groupings apply.

tools/bt/src/main/java/org/applecommander/bastools/tools/bt/Main.java

@@ -17,15 +17,6 @@
  */
 package org.applecommander.bastools.tools.bt;
 
-import java.io.*;
-import java.nio.file.Files;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Optional;
-import java.util.Queue;
-import java.util.concurrent.Callable;
-import java.util.function.Function;
-
 import io.github.applecommander.applesingle.AppleSingle;
 import org.applecommander.bastools.api.*;
 import org.applecommander.bastools.api.model.Program;
@@ -34,11 +25,21 @@ import org.applecommander.bastools.api.model.Token.Type;
 import org.applecommander.bastools.api.proofreaders.*;
 import org.applecommander.bastools.api.visitors.ByteVisitor;
 import picocli.CommandLine;
+import picocli.CommandLine.ArgGroup;
 import picocli.CommandLine.Command;
 import picocli.CommandLine.Help.Visibility;
 import picocli.CommandLine.Option;
 import picocli.CommandLine.Parameters;
-import picocli.CommandLine.ArgGroup;
+
+import java.io.*;
+import java.nio.file.Files;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.Queue;
+import java.util.concurrent.Callable;
+import java.util.function.BiConsumer;
+import java.util.function.Function;
 
 import static picocli.CommandLine.Model.UsageMessageSpec.SECTION_KEY_FOOTER;
 
@@ -218,7 +219,7 @@ public class Main implements Callable<Integer> {
 			program.accept(Visitors.variableReportVisitor());
 		}
         if (proofReader.proofReaderFn != null) {
-            program.accept(proofReader.proofReaderFn.apply(config));
+            proofReader.proofReaderFn.accept(config, program);
         }
 
 		ByteVisitor byteVisitor = Visitors.byteVisitor(config);
@@ -346,36 +347,54 @@ public class Main implements Callable<Integer> {
     }
 
     public static class ProofReaderSelection {
-        Function<Configuration,Visitor> proofReaderFn;
+        BiConsumer<Configuration,Program> proofReaderFn;
 
         @Option(names = "--checkit", description = "Apply Nibble Checkit (ca 1988) to code")
         public void selectNibbleCheckit(boolean flag) {
-            this.proofReaderFn = NibbleCheckit::new;
+            this.proofReaderFn = (c,p) -> {
+				NibbleCheckit proofreader = new NibbleCheckit(c);
+				proofreader.addProgram(p);
+			};
         }
 
         @Option(names = "--proofreader", description = "Apply Compute! Apple Automatic Proofreader (ca 1985) to code")
         public void selectComputeProofreader(boolean flag) {
-            this.proofReaderFn = ComputeAutomaticProofreader::new;
+            this.proofReaderFn = (c,p) -> {
+				ComputeAutomaticProofreader proofreader = new ComputeAutomaticProofreader(c);
+				proofreader.addProgram(p);
+			};
         }
 
         @Option(names = "--apple-checker", description = "Apply Nibble Apple Checker 3.0 (ca 1982) to code")
         public void selectNibbleAppleChecker(boolean flag) {
-            this.proofReaderFn = NibbleAppleChecker::new;
+            this.proofReaderFn = (c,p) -> {
+				NibbleAppleChecker proofreader = new NibbleAppleChecker(c);
+				proofreader.addProgram(p);
+			};
         }
 
         @Option(names = { "--key-perfect-2", "--kp2" }, description = "Apply MicroSPARC Key Perfect V2 (ca 1981) to code")
         public void selectKeyPerfectV2(boolean flag) {
-            this.proofReaderFn = MicrosparcKeyPerfect2::new;
+            this.proofReaderFn = (c,p) -> {
+				MicrosparcKeyPerfect2 proofreader = new MicrosparcKeyPerfect2(c);
+				proofreader.addProgram(p);
+			};
         }
 
         @Option(names = { "--key-perfect-4", "--kp4" }, description = "Apply MicroSPARC Key Perfect V4 (ca 1981) to code")
         public void selectKeyPerfectV4(boolean flag) {
-            this.proofReaderFn = MicrosparcKeyPerfect4::new;
+            this.proofReaderFn = (c,p) -> {
+				MicrosparcKeyPerfect4 proofreader = new MicrosparcKeyPerfect4(c);
+				proofreader.addProgram(p);
+			};
         }
 
 		@Option(names = { "--key-perfect-5", "--kp5" }, description = "Apply MicroSPARC Key Perfect V5 (ca 1985) to code")
 		public void selectKeyPerfectV5(boolean flag) {
-			this.proofReaderFn = MicrosparcKeyPerfect5::new;
+			this.proofReaderFn = (c,p) -> {
+				MicrosparcKeyPerfect5 proofreader = new MicrosparcKeyPerfect5(c);
+				proofreader.addProgram(p);
+			};
 		}
     }
 }