Power-Programmierung/CD1.mdf/logo/labybug/ladybg.lst

File List | 1984-04-20 | 141KB | 6,403 lines

 LADYBUG GRAPHICS

 IBM/PC REFERENCE MANUAL

 VERSION 1.0D





 21 April 1984









 David N. Smith

 44 Ole Musket Lane
 Danbury, CT 06810









 (c) Copyright 1983 and 1984 by David N. Smith
 All Rights Reserved.





















 PREFACE


 LadyBug is an implementation of LOGO Turtle Graphics.  It is
 distributed as "User-Supported" software which means that you do
 not have to pay for it.  You can copy it, give it away, or do
 anything else with it except sell it.

 If you find that it is useful, you are invited to make a donation
 of $35 to the author.  The donation is voluntary and in no way
 should be considered as payment for software or services.

 Under no circumstances should school teachers feel any obligation
 to make a donation.  One teacher said she has $100 per year for
 software, shared between three teachers, and that she would send
 a donation when they raised money from selling candy.  If that is
 your kind of circumstance, please accept LadyBug with the
 author's compliments.

 The author is:

    David N. Smith
    44 Ole Musket Lane
    Danbury, CT 06810

 The author can also be reached by US mail or EMAIL on CompuServe
 to userid 73145,153.  Please do not phone.



 DISCLAIMER

 LADYBUG COMES WITH NO WARRANTIES OF ANY KIND; IT IS AVAILABLE AS
 IS. The author would like to know of problems that users have but
 makes no promise or guarantee that any problem will be fixed.
 Please don't feel that a donation is necessary to report a
 problem or suggest an improvement; it isn't!  In fact, exactly
 the opposite might be true.

 IN NO EVENT WILL THE AUTHOR BE LIABLE FOR ANY DAMAGES, INCLUDING
 ANY LOST PROFITS, LOST SAVINGS, FAILURE TO EDUCATE, OR OTHER
 INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF OR
 INABILITY TO USE THIS PROGRAM, EVEN IF THE AUTHOR HAS BEEN
 ADVISED OF THE POSSIBILITY OF SUCH DAMAGES, OR FOR ANY CLAIM BY
 ANY OTHER PARTY.











                                                            Page i






                                                           Preface


 COPYING LADYBUG

 Educational institutions, clubs, and other nonprofit organiza-
 tions as well as individuals are granted permission to freely
 copy LadyBug and its documentation and share them with their
 members or students, or individuals with their friends, so long
 as:

 1.  No price is charged for the software or documentation.
     However, clubs and other nonprofit organizations may charge a
     distribution fee of up to $6 to cover expenses.

 2.  Neither the program nor its documentation are modified in any
     way and are distributed together.

 Other organizations, and individuals, are allowed to copy LadyBug
 only if done without charge and so long as the other rules above
 are followed.

 Educational institutions, clubs, and other nonprofit organiza-
 tions may make printed copies of this document for distribution
 to members, or students of the institution, provided that any
 price charged does not exceed the actual cost of the duplication
 of the copy, and provided that the document is reproduced in its
 entirety including all copyright and restrictive notices.

 NOTICE: LadyBug is NOT in the public domain.  The author retains
 ownership of the program and its copyright.



 USER SUPPORTED SOFTWARE

 User-supported software was conceived by Andrew Fluegelman of
 Headlands Press for PC-TALK.  He used the name FreeWare(tm).  Jim
 Button, distributor of PC-FILE, coined the term user-supported
 software.

 User-supported does NOT mean that the user must support herself.
 It means that the user herself supports the idea of freely
 distributed software.















                                                           Page ii






                                                           Preface


 SOURCE

 LadyBug is written in Basic and then compiled.  Source is NOT
 distributed nor is it available.



 HOW TO GET LADYBUG

 If you do not have LadyBug, or if your copy is not current, you
 can get a new copy by sending the author a diskette and a postage
 paid mailer.  You get LadyBug with documentation on disk.  In any
 case, please mark LADYBUG on the OUTSIDE of the envelope.  Send
 no money; LadyBug is free.

 LadyBug is available from an ever increasing list of other
 sources.  In particular the Young Peoples LOGO Association
 distributes LadyBug as well as hundreds of procedures written in
 LOGO.  Chapter 1 gives their address.





































                                                          Page iii









 TABLE OF CONTENTS


 1. ABOUT LADYBUG AND LOGO.................................  1
   1.1. LadyBug Features...................................  2
   1.2. LadyBug Requirements...............................  2
   1.3. Additions and Changes From Version 0.9.............  3
   1.4. Changes made in Version 1.0........................  3
   1.5. Why not LadyBug?...................................  4
   1.6. LadyBug Procedure Library..........................  4
   1.7. Thanks To ---......................................  4

 2. RUNNING LADYBUG........................................  5
   2.1. Before You Run LadyBug.............................  5
   2.2. Starting...........................................  5
   2.3. LadyBug Function Keys..............................  5
   2.4. Trying Things......................................  6
   2.5. Setting Up a LadyBug Diskette......................  7
   2.6. If Something Goes Wrong............................  8

 3. THE WORKSPACE..........................................  9

 4. THE LADYBUG SCREENS....................................  10
   4.1. The Graphics Screen................................  10
   4.2. The Text Screen....................................  11
   4.3. The Editing Screen.................................  11
   4.4. Using Two Displays.................................  11

 5. THINGS WHICH MAKE UP COMMANDS..........................  12
   5.1. Words..............................................  12
   5.2. Numbers............................................  12
   5.3. Lists..............................................  12
   5.4. Strings............................................  13
   5.5. About Capital Letters..............................  13
   5.6. Expressions........................................  13

 6. GRAPHICS COMMANDS......................................  14
   6.1. BACK length    (Abbreviated BK)....................  14
   6.2. BACKGROUND color    (Abbreviated BG)...............  14
   6.3. CLEARSCREEN    (Abbreviated CS)....................  15
   6.4. CLIP...............................................  15
   6.5. DRAW...............................................  15
   6.6. FORWARD length   (Abbreviated FD)..................  16
   6.7. HIDEBUG    (Abbreviated HB)........................  16
   6.8. HIDETURTLE    (Abbreviated HT).....................  16
   6.9. HOME...............................................  16
   6.10. LEFT angle   (Abbreviated LT).....................  16
   6.11. NOCLIP............................................  17
   6.12. NODRAW   (Abbreviated ND).........................  17
   6.13. NOWRAP............................................  17
   6.14. NOWINDOW..........................................  17
   6.15. PAINT paintcolor bordercolor......................  18
   6.16. PALETTE palettenumber.............................  18
   6.17. PENCOLOR color   (Abbreviated PC).................  18


                                                           Page iv






                                                 Table of Contents


   6.18. PENDOWN   (Abbreviated PD)........................  19
   6.19. PENUP   (Abbreviated PU)..........................  19
   6.20. RIGHT angle   (Abbreviated RT)....................  19
   6.21. SETHEADING angle   (Abbreviated SETH).............  19
   6.22. SETBG color.......................................  20
   6.23. SETPAL palette....................................  20
   6.24. SETPC color.......................................  20
   6.25. SETSCRUNCH n   (Also: .SETSCRUNCH)................  20
   6.26. SETX xcoord.......................................  20
   6.27. SETXY xcoord ycoord...............................  21
   6.28. SETY ycoord.......................................  21
   6.29. SHOWBUG   (Abbreviated SB)........................  21
   6.30. SHOWTURTLE   (Abbreviated ST).....................  21
   6.31. WINDOW............................................  22
   6.32. WRAP..............................................  22

 7. SOUNDS.................................................  23
   7.1. BEEP...............................................  23
   7.2. PLAY string........................................  23
   7.3. TONE frequency n...................................  24

 8. INPUT AND OUTPUT.......................................  25
   8.1. CLEARINPUT.........................................  25
   8.2. PRINT word   (Abbreviated PR)......................  25
   8.3. PRINT1 word   (Abbreviated PR1)....................  25
   8.4. TYPE word..........................................  26

 9. TEXT MODE..............................................  27
   9.1. CLEARTEXT   (Abbreviated CT).......................  27
   9.2. CURSOR column row..................................  27
   9.3. SETWIDTH columns...................................  28
   9.4. TEXTCOLUMNS columns   (Abbreviated TCOLS)..........  28

 10. CONTROL COMMANDS......................................  29
   10.1. EDIT procname ...   (Abbreviated ED)..............  29
   10.2. EDIT ALL..........................................  29
   10.3. END...............................................  29
   10.4. ERROR message.....................................  30
   10.5. FOREVER list......................................  30
   10.6. GOODBYE   (Abbreviated BYE).......................  30
   10.7. IF condition THEN action..........................  30
   10.8. IF condition [action].............................  31
   10.9. IF condition THEN action1 ELSE action2............  31
   10.10. IF condition [action1] [action2].................  32
   10.11. IFFALSE list.....................................  32
   10.12. IFTRUE list......................................  32
   10.13. LOCAL variablename...............................  33
   10.14. MAKE "variablename value.........................  34
   10.15. OUTPUT value   (Abbreviated OP)..................  34
   10.16. RANDOMIZE number.................................  35
   10.17. REPEAT number list...............................  35
   10.18. RUN list.........................................  35
   10.19. STOP.............................................  36
   10.20. TEST condition...................................  36


                                                            Page v






                                                 Table of Contents


   10.21. TOPLEVEL.........................................  36
   10.22. WAIT time........................................  36
   10.23. WHILE condition list.............................  36

 11. MANAGING THE WORKSPACE................................  37
   11.1. CATALOG   (Abbreviated CAT).......................  37
   11.2. CLEARWS...........................................  37
   11.3. DEFINE "name list.................................  37
   11.4. EDIT procname ....................................  38
   11.5. EDIT ALL..........................................  38
   11.6. ERASE procedurename...............................  38
   11.7. ERASE ALL.........................................  38
   11.8. ERASEFILE filename................................  39
   11.9. ERNAME variablename...............................  39
   11.10. ERNAME ALL.......................................  39
   11.11. LOAD filename....................................  39
   11.12. PRINTOUT name   (Abbreviated PO).................  39
   11.13. READ filename....................................  40
   11.14. SAVE filename....................................  40
   11.15. TO procname inputs...............................  40

 12. RUNNING AND DEBUGGING PROCEDURES......................  41
   12.1. Running Procedures................................  41
   12.2. Pausing Procedures................................  41
   12.3. Editing Active Procedures.........................  42
   12.4. CONTINUE    (Abbreviated CO)......................  42
   12.5. NOTRACE...........................................  42
   12.6. PAUSE.............................................  42
   12.7. TOPLEVEL..........................................  43
   12.8. TRACE.............................................  43
   12.9. ;  (comment)......................................  43

 13. NUMBERS AND COMPUTATIONS..............................  44
   13.1. Numbers...........................................  44
   13.2. Numeric and Mathematical Values...................  44
   13.3. Other Words.......................................  47
   13.4. Expressions Resulting in Numbers..................  48
   13.5. Expressions Resulting in True or False............  49
   13.6. Procedures........................................  50

 14. WORKSPACES WITH TOOLS.................................  52
   14.1. AND  t/f  t/f.....................................  52
   14.2. FOREVER list......................................  52
   14.3. MAX value1 value2.................................  52
   14.4. MIN value1 value2.................................  52
   14.5. OR  t/f  t/f......................................  53
   14.6. WAIT time.........................................  53
   14.7. WHILE [condition] [commands]......................  53
   14.8. XOR  t/f  t/f.....................................  53







                                                           Page vi






                                                 Table of Contents


 15. INTRODUCTION TO THE LADYBUG EDITOR....................  54
   15.1. About the Editor..................................  54
   15.2. Invoking the Editor...............................  54
   15.3. The LadyBug Editor Keys...........................  55

 16. HINTS ON USING LADYBUG................................  57
   16.1. Printing the Screen On an IBM or Epson Printer....  57
   16.2. Printing the Screen On Other Printers.............  57
   16.3. The READ Command..................................  57
   16.4. Tailoring LadyBug: The Profile....................  58
   16.5. Performance Hints.................................  58

 APPENDIX A. ABOUT THE LADYBUG EDITOR......................  59
   A.1. The LadyBug Editor Keys............................  59

 APPENDIX B. THE PLAY COMMAND..............................  62
   B.1. Music Commands.....................................  62
   B.2. Examples of Play Statements........................  65

 APPENDIX C. A GUIDE TO EXAMPLE PROCEDURES.................  66
   C.1. BCAKE..............................................  66
   C.2. C..................................................  66
   C.3. DYNA...............................................  66
   C.4. DRAGON.............................................  67
   C.5. DUOPOLY............................................  67
   C.6. HILBERT............................................  67
   C.7. INSPI..............................................  67
   C.8. LUDWIG.............................................  68
   C.9. MISC...............................................  68
   C.10. POLY..............................................  68
   C.11. POLYSPI...........................................  69
   C.12. RAIL..............................................  69
   C.13. SLINKY............................................  69
   C.14. SNOWFLAK..........................................  70
   C.15. SPIRO.............................................  70
   C.16. SOUNDS............................................  70
   C.17. SPINSQ............................................  71
   C.18. TREES.............................................  71

 APPENDIX D. FORMAT AND CONTENTS OF SAVED WORKSPACES.......  72

 APPENDIX E. REDEFINING THE NAMES OF PRIMITIVES............  73
   E.1. .PRIMSYN [list]....................................  73

 APPENDIX F. HACKERS ONLY..................................  74
   F.1. .DEBUG.............................................  74
   F.2. .STACK.............................................  74
   F.3. .SYMTAB............................................  74
   F.4. Names that return values...........................  74







                                                          Page vii






                                                 Table of Contents


 APPENDIX G. ERROR MESSAGES................................  76

 APPENDIX H. LIMITS AND CAPACITIES.........................  79





















































                                                         Page viii









 1. ABOUT LADYBUG AND LOGO


 LadyBug is a graphics language based on LOGO Turtle Graphics.  It
 contains most of the graphics commands, procedure making
 commands, and control commands from the Apple II(1)
 implementation of LOGO done by Terrapin, Inc.  with additions for
 compatibility with IBM Logo.

 Apple LOGO is described in the book LOGO FOR THE APPLE II by
 Harold Abelson, published by McGraw-Hill in 1982.  It is very
 similar to other versions for the Apple II, IBM PC, Texas
 Instruments, and TRS-80(2) computers.

 This manual describes the LadyBug language but is not an
 introduction to LOGO.  We highly recommend the book LOGO FOR THE
 APPLE II for its very understandable presentation of LOGO and for
 its many examples.

 DISCOVERING APPLE LOGO by David D. Thornburg is another very
 readable, although less complete, introduction to LOGO.  It was
 published by Addison-Wesley in 1983.

 For children, or adults who are going to work with children, the
 book LEARNING WITH LOGO, Daniel Watt, McGraw-Hill, 1983, is
 highly recommended.  It is written by a person who is both an
 elementary teacher, and who has worked with the LOGO group at MIT
 for many years.

 The book TURTLE GEOMETRY, Abelson and diSessa, MIT Press, 1980 is
 recommended for adults and advanced High School students.  It
 takes the form of a college text book on mathematics using Turtle
 Graphics as the mechanism.

 A good source of ideas and programs is the YOUNG PEOPLES' LOGO
 ASSOCIATION, 1208 Hillsdale Drive, Richardson, TX 75081.  On
 CompuServe, YPLA can be reached at 70130,250 and on the Source
 they are T10143.  YPLA publishes a monthly newsletter and has a
 large library of public domain LOGO software for a wide variety
 of machines.

 Of course, MINDSTORMS, Seymour Pappert, Basic Books, 1980 is the
 ultimate source of WHY LOGO.







 ____________________

 (1) Apple II is a Trademark of Apple, Inc.
 (2) TRS-80 is a Trademark of Tandy.


                                                            Page 1






                                            About LadyBug and LOGO


 1.1. LADYBUG FEATURES

 LadyBug is a version of LOGO patterned after the Apple II
 implementation developed by Terrapin, Inc. and with additions to
 make it compatible with many IBM LOGO commands.

 LadyBug features include:

 -   Sounds; a PLAY statement and a TONE statement.
 -   Major graphics support (32 primitives).
 -   Painting of areas.
 -   Clipping of drawings (as well as wraparound).
 -   Support for using both displays if both are present.
 -   Text mode support of the whole screen.

 -   A fast full screen editor.
 -   Procedure control commands (24 primitives).
 -   Workspace management (14 primitives).
 -   Pausing and resuming procedures.
 -   Tracing of procedures.

 -   Floating point and integer arithmetic.
 -   32 builtin graphics and mathematical functions.
 -   6 arithmetic operations and 6 relational operations.

 -   Interactive HELP facility.
 -   Workspaces of tools and procedures.

 The major features missing (compared to Apple LOGO) are:

 -   Many list manipulation primitives.
 -   Variable numbers of parameters to primitives.
 -   Saving screen images.  (Procedures can be saved though).



 1.2. LADYBUG REQUIREMENTS

 LadyBug requires a system with at least:

 -   128K of memory.
 -   One single sided disk drive.
 -   A graphics adaptor.
 -   A graphics display of any kind.  Color is supported only on a
     color display; 80 column editing is supported only on a high
     resolution monitor.  A color TV set will work but colors will
     not be accurate.
 -   DOS 1.1, 2.0, or 2.1.  (DOS 1.0 has not been tested.)
 -   An IBM PC  or compatible machine.

 The distribution diskette is double sided and requires DOS 1.1 or
 later.  Files for execution of LadyBug can be copied to a single
 sided diskette.



                                                            Page 2






                                            About LadyBug and LOGO


 The IBM Monochrome Display is also supported, if present, for
 editing and when in text mode.  References in this document to
 "the Monochrome display" refer to the IBM Monochrome Display and
 not to a black and white graphics monitor.



 1.3. ADDITIONS AND CHANGES FROM VERSION 0.9

 The changes made in version 1.0, as compared to version 0.9,
 include:

 -   returning values from procedures;
 -   help key;
 -   pausing procedures and then continuing;
 -   SETSCRUNCH to adjust aspect ratios;
 -   TEST, IFTRUE, and IFFALSE commands;
 -   some list support;
 -   some IBM LOGO syntax compatibility;
 -   expanded limits for the size of procedures, number of lines
     to edit, and sizes of constants;
 -   text screen support;
 -   tools workspaces; and
 -   many new builtin functions.

 Many smaller changes have also been made.  In addition the manual
 has been expanded with additional information, examples, and an
 index.



 1.4. CHANGES MADE IN VERSION 1.0


 -   .PRIMSYN command for adding synonyms for primitive commands.
 -   Many fixes to problems.  These are listed in the file
     STATUS.LST on the distribution diskette.

 If other enhancements are made after this document is prepared,
 they will be given in the file STATUS.LST on the distribution
 diskette.















                                                            Page 3






                                            About LadyBug and LOGO


 1.5. WHY NOT LADYBUG?

 LadyBug was written as an introduction to LOGO and Turtle
 Graphics for the author's children prior to the availability of a
 commercial version of LOGO for the PC.  Thoughts of distribution
 came later as others asked for copies and suggested that it be
 further distributed.

 The author recommends that those with a serious need for LOGO
 investigate the use of a commercial version of LOGO rather than
 LadyBug.  There are several reasons:

 -   LadyBug is slower.
 -   LadyBug doesn't do as much.
 -   LadyBug is not supported in the same sense the commercial
     versions are supported.  If you have a bug, then you might
     have a bug forever.
 -   LadyBug will not grow and progress significantly with time.
 -   LadyBug is not as well documented.

 In particular, the IBM version of LOGO is a very powerful
 implementation which also runs under PC/DOS.  It stores
 workspaces in a manner similar to LadyBug; conversion to it
 should not be difficult.



 1.6. LADYBUG PROCEDURE LIBRARY

 There is not much of a library now except as described in the
 Tools chapter and in the Appendix on example procedures.  I hope
 that LadyBug users will contribute procedures to a library so
 that other users can share their efforts.  Contribute them either
 to the author or to the Young Peoples LOGO Association.



 1.7. THANKS TO ---

 Thanks to the inventors of LOGO for inventing it.

 Thanks to my children for playing with LadyBug.

 Thanks to ReadiWriter, a very powerful text formatter, for making
 it so easy to do a document this complex.  In particular, the
 indexing was a breeze; without a program like ReadiWriter there
 wouldn't have been an index.

 Thanks to all of those who have made suggestions, found bugs, and
 helped out in many other ways.

 And thanks to my wife for putting up with me while I wrote
 LadyBug.



                                                            Page 4









 2. RUNNING LADYBUG



 2.1. BEFORE YOU RUN LADYBUG

 The LadyBug diskette should be backed up.  Never run the only one
 you have if you value being able to run LadyBug tomorrow.

 LadyBug is initially distributed on double sided diskettes.  If
 you have single sided drives you should get someone with double
 sided drives to copy the files onto diskettes formatted for
 single sided use.

 Although LadyBug will run with the diskette setup as distributed,
 a section below describes how to set up working disks in order to
 maximize the amount of working space and to make them self
 booting.



 2.2. STARTING

 Boot DOS up.  Put the LadyBug diskette into the A: drive.  See
 the DOS manual for information about how to make the LadyBug
 diskette contain enough of DOS to boot up itself.  With an
 AUTOEXEC.BAT file on the diskette you can have LadyBug start up
 automatically when the machine is turned on.

 Type "LADYBUG".  After a few seconds you will be in LadyBug
 command mode.



 2.3. LADYBUG FUNCTION KEYS

 The LadyBug function keys control how LadyBug programs run or
 stop them from running.  They may be used any time that LadyBug
 is running.  When LadyBug is waiting for input you will have to
 press the enter key before the action takes effect.  (In the
 editor, the function keys have different meanings.)

 F1
     Stop a running procedure and return to the command level from
     which it was invoked.

 F3
     Display the help menu.

 F5
     Pause execution of a procedure or command and re-enter
     LadyBug command mode.  Procedures and commands can be run and
     then the paused command can be restarted by typing CONTINUE
     (or CO).  F1 will stop procedures invoked from a pause level


                                                            Page 5






                                                   Running LadyBug


     and return to that pause level.  Procedures or commands run
     from a pause level can themselves be paused, etc.

 F9
     Switch on or off TRACE mode.  When it is on, each command
     that is executed is displayed and LadyBug pauses for you to
     press any key.

 F10
     Hide or unhide the display of the LadyBug herself.  (She
     looks like an arrow due to the radiation armor she wears!)
     PROCEDURES RUN FASTER TWO OR THREE TIMES FASTER WHEN SHE IS
     HIDDEN but are easier to understand when she is visible.



 2.4. TRYING THINGS

 The procedure POLY is already defined when LadyBug starts up.
 (POLY is a simple and commonly used illustration of LOGO.)  To
 try something, type DRAW.  DRAW tells LadyBug you want to do
 graphics; it clears the screen and positions the LadyBug at the
 center of the screen.  Then type one of these:

    poly 100 100
    poly 100 144
    poly 100 162

 Press F1 to stop the drawing; it will continue to run, retracing
 its path, until you stop it.  If you press F10 while the figure
 is being drawn then the LadyBug hides.  Press it again to get her
 back.

 Type DRAW to clear the screen and to reset the LadyBug to her
 home position.

 There are many examples which come with LadyBug; they are briefly
 described in appendix C.  Try this:

    read "polyspi
    clip
    polyspi 5 144 5

 Press F1 to stop it.  Then try:

    draw
    polyspi 1 45 1

 Or try:

    draw
    polyspi 5 175 5

 POLY is a three statement procedure.  POLYSPI is too.  The wide


                                                            Page 6






                                                   Running LadyBug


 variations in each come from minor changes in how far a line is
 drawn and how much of a turn is then made.  It is difficult to
 believe that the three POLYSPI drawings come from the SAME
 trivial program.



 2.5. SETTING UP A LADYBUG DISKETTE

 LadyBug will run from the diskette it is distributed on.
 However, this diskette has files on it which are not needed for
 running LadyBug.  The following procedure describes how to build
 a diskette which holds only those things you need.

 1.  Format a diskette with the DOS FORMAT command.  Use the /S
     option if you want it to automatically startup when you turn
     on the machine.

 2.  Put the diskette from step one into the B: drive.  Put the
     LadyBug diskette into the A: drive.

 3.  Issue these commands:

        copy a:*.exe b:
        copy a:help*.bug b:
        copy a:profile.bug b:

     These files should take about 100K leaving about 60K on a DOS
     1.1 single sided diskette, 80K on a DOS 2.0 single sided
     diskette, 220K on a DOS 1.1 double sided diskette, and 260K
     on a DOS 2.0 double sided diskette.

     Files with an extension of BUG contain LadyBug procedures.
     The ones copied above are necessary for LadyBug to function
     properly.  Other BUG files contain tools or demonstration
     programs and can be copied as needed.  If you want them all,
     type:

        copy a:*.bug b:

 4.  If you want the diskette to automatically start LadyBug when
     the power is turned on, you need to create an AUTOEXEC.BAT
     file.  The DOS manual describes how to do this.  The file
     should contain the following lines:

        date
        time
        ladybug








                                                            Page 7






                                                   Running LadyBug


 2.6. IF SOMETHING GOES WRONG

 The appendix "Error Messages" lists the error messages that
 LadyBug puts out.  Two of these messages indicate a problem
 within LadyBug.  Hopefully these will never be printed but if
 they are it is very important that you communicate them to the
 author.  These are:

    FATAL ERROR n AT m
    INTERNAL ERROR n

 The "n" and "m" are numbers which vary from error to error and
 which are very important in determining what happened.

 LadyBug will almost always recover from these errors and allow
 you to continue without loss of data.  However, it is recommended
 that you stop LadyBug as soon as you can afterwards and reload a
 fresh copy.  Also, do not save the workspace (except into a new
 file) without examining it to make sure the error did not cause
 damage to it.




































                                                            Page 8









 3. THE WORKSPACE


 LadyBug provides a work area in which you keep variables and
 procedures.  This work area is called a "workspace".

 The workspace initially contains only the procedure POLY.  Many
 LadyBug commands add to, modify things in, or remove things from
 the workspace.

    COMMAND    ACTION
    CLEARWS    Delete everything in the workspace
    EDIT       Add or change procedures
    ERASE      Delete a procedure or all procedures
    ERNAME     Delete a variable or all variables
    LOAD       Load things from another workspace
    SAVE       Save the workspace on disk
    TO         Define a procedure

 These commands are described elsewhere in this manual.

 As you work you add things to your current workspace.  When you
 are done you can either type BYE and leave LadyBug without saving
 the workspace or you can type SAVE and save it first.  SAVE
 requires that you name the workspace.  When you next start you
 can READ (or LOAD) that workspace and continue.

 You can have several workspaces for several projects or classes.
 If you have students, each can have her own workspace.

 The things that can go into a workspace are:

 Procedures
     Procedures are lists of commands that you want to run.  They
     have names, such as "poly", "fred", or "butterfly", that you
     make up.  Later on we will talk about how to create
     procedures.

 Variables
     Variables are named values.  Variables have names, such as
     "x", "fred", or "length", that you also make up.  Variables
     often are written with a semicolon like this:

        :x    :fred    :length

     The semicolon asks LadyBug to get the current value of the
     variable and use it.  We will see these in some examples
     before we get back to discussing variables in more detail.








                                                            Page 9









 4. THE LADYBUG SCREENS


 This chapter describes the different views of LadyBug seen on the
 screen.

 The TEXT SCREEN shows text.  When the text screen is current,
 LadyBug is said to be in "Text Mode".

 The GRAPHICS SCREEN shows graphics.  When the graphics screen is
 current, LadyBug is said to be in "Graphics Mode".

 The EDIT SCREEN shows procedures which can be changed.  When the
 edit screen is current, LadyBug is said to be "in the editor".



 4.1. THE GRAPHICS SCREEN

 When LadyBug starts up it is in text mode.  To get into graphics
 mode, type "DRAW".  In graphics mode, commands which draw are
 allowed.  Commands which display text do so in a small area at
 the bottom of the screen.(3) If you forget to type DRAW, LadyBug
 will automatically switch to the graphics screen when you issue
 any command which needs it.

 Graphics mode is re-entered each time you give the DRAW command.

 The graphics screen is 300 units high by 500 units wide.  The
 center is the origin.(4)

 The LadyBug starts at the center of the screen facing towards the
 top of the screen.  This direction has a heading of zero.  Turns
 to the right are considered positive and to the left are
 considered negative.











 ____________________

 (3) This area is two lines of up to 80 characters total.
 (4) Note that the coordinates of the LadyBug screen do not map
 exactly to the coordinates of the computers screen.  This is
 because there is nothing magic about the number of dots on the
 computers screen; different modes and different computers can
 have differing numbers of dots.


                                                           Page 10






                                               The LadyBug Screens


 150  +----+----+----+----+----+----+----+----+----+----+
      |                                                 |
      |                                                 |
 100  +                                                 +
      |                                                 |
      |                                                 |
  50  +                                                 +
      |                                                 |
      |                                                 |
  0   +                        + (center)               +
      |                                                 |
      |                                                 |
 -50  +                                                 +
      |                                                 |
      |                                                 |
 -100 +                                                 +
      |                                                 |
      |                                                 |
 -150 +----+----+----+----+----+----+----+----+----+----+
    -250 -200 -150 -100  -50   0    50  100  150  200  250

                  Graphics Screen Coordinates



 4.2. THE TEXT SCREEN

 In text mode, LadyBug does not allow graphics but does allow a
 full screen of text.  Text mode is entered with the NODRAW
 command.



 4.3. THE EDITING SCREEN

 The editing screen replaces whichever screen is active when the
 EDIT or TO commands are given.  When editing ends, the previous
 screen type is restored but the screen is clear.



 4.4. USING TWO DISPLAYS

 If present, the IBM Monochrome display is used as the text screen
 and the editing screen.  The graphics display always contains the
 graphics screen.










                                                           Page 11









 5. THINGS WHICH MAKE UP COMMANDS


 This chapter describes the kinds of things which are used in
 LadyBug commands.



 5.1. WORDS

 Words are groups of characters separated from each other by
 blanks.

 Examples:

    fred  *****  $129.50

 Each of "fred", "*****", and "$129.50" are words.

 Some special words, such as those starting with a left bracket
 ("[") or a quote mark may contain blanks; see below.



 5.2. NUMBERS

 Numbers are special kinds of words.  Numeric values come in two
 types: integer, and floating point.

 Integer numbers have only whole number values.  These values must
 be in the range of -32768 to 32767.  Floating point numbers have
 whole number and fractional values and an optional exponent.

 Examples:

    1    954    1.2    1.2e12

 Numbers are described in more detail later.



 5.3. LISTS

 Lists start with a left bracket and end with a right bracket.
 Examples of lists include:

    [This is a list of words]
    [ [This is a list] [of lists] ]

 Within a list, the number of left and right brackets are counted.
 The end of the list occurs after the right bracket which
 corresponds to the starting left bracket.  If a line ends before
 the ending bracket, it is assumed to be present.



                                                           Page 12






                                     Things Which Make Up Commands


 5.4. STRINGS

 Strings are words which start with a quote mark.  Examples of
 strings are:

    "frank
    "(

 Strings may contain characters, such as a left parenthesis, which
 would otherwise be taken as something else.  Strings can also
 contain blanks:

 Example:

    "'This is a string with blanks'

 The second character is an apostrophe; this means that every
 character up to the next apostrophe (or the end of the line) is a
 part of the word.

 Strings may not contain left ([) or right (]) brackets.



 5.5. ABOUT CAPITAL LETTERS

 In this document command names are shown in capital letters.
 LadyBug will accept either capitals or lowercase for any command
 name, file identifier, procedure, variable, or other word special
 to LadyBug.



 5.6. EXPRESSIONS

 Numbers, and variables with numbers as their values, can be
 combined into expressions.  Everywhere that LadyBug is looking
 for a number you can write an expression.  Expressions will be
 described in detail later in this manual.

 Examples:

    2 + 4
    2 + :a
    4 * sin :angle











                                                           Page 13









 6. GRAPHICS COMMANDS


 This section describes the LadyBug graphics commands.  These
 commands move and turn the LadyBug, paint areas, and control
 which colors are used.

 If issued in text mode, they cause graphics mode to be entered.
 The text on the text screen is lost.  Exceptions are WINDOW,
 NOWINDOW, WRAP, NOWRAP, CLIP, NOCLIP, and SETSCRUNCH which do not
 cause graphics mode to be entered, and NODRAW which terminates
 graphics mode and starts up text mode.



 6.1. BACK LENGTH    (ABBREVIATED BK)

           Takes one number as input.  Moves the LadyBug
           backwards, that is in the opposite way from which it is
           facing, the distance given by the number.  The distance
           must be between -3000 and +3000.  Negative numbers mean
           to move in the opposite direction (i.e. forward).

           Examples:

              back 50
              back :a + 1
              bk 2
              bk -50



 6.2. BACKGROUND COLOR    (ABBREVIATED BG)

           Takes a number from 0 through 15 as input.  Sets the
           color according to the following table:

                0   Black           8   Gray
                1   Blue            9   Light Blue
                2   Green          10   Light Green
                3   Cyan           11   Light Cyan
                4   Red            12   Light Red
                5   Magenta        13   Light Magenta
                6   Brown          14   Yellow
                7   White          15   High-intensity White

           The change takes place immediately for the entire
           screen.  Until you set a background, it is black.








                                                           Page 14






                                                 Graphics Commands


           Examples:

              background 8
              bg 0



 6.3. CLEARSCREEN    (ABBREVIATED CS)

           Takes no inputs.  Clears the graphics screen but does
           not change LadyBug's position or direction.

           NOTE:  In some LOGO systems CLEARSCREEN also puts the
           LadyBug back at the home position.  For this function,
           see the DRAW command.



 6.4. CLIP

           Takes no inputs.  Tells Ladybug that lines drawn by the
           LadyBug are to be trimmed at the edge of the screen.
           If WRAP has previously been given, it is turned off.
           (That is, CLIP also does a NOWRAP.)  See WRAP for more
           information.

           The screen acts like a window onto a large flat sheet
           on which the LadyBug draws.  Only that part which is
           visible through the window is seen.

           Try:

              clip
              draw
              poly 250 170



 6.5. DRAW

           Takes no inputs.  Exits from the text mode and enters
           graphics mode.  Clears the graphics screen and resets
           LadyBug to her home position and direction.  (Also see
           the HOME command.)












                                                           Page 15






                                                 Graphics Commands


 6.6. FORWARD LENGTH   (ABBREVIATED FD)

           Takes one number as input.  Moves the LadyBug forward,
           that is in the direction it is facing, the distance
           given by the number.  The distance must be between
           -3000 and +3000.  Negative numbers mean to move in the
           opposite direction (i.e. backward).

           Examples:

              forward 50
              fd 50
              fd -30



 6.7. HIDEBUG    (ABBREVIATED HB)

           Takes no inputs.  Makes the LadyBug disappear from the
           screen.  May also be written as HIDETURTLE (abbreviated
           as HT).  See also SHOWBUG in this chapter.



 6.8. HIDETURTLE    (ABBREVIATED HT)

           Takes no inputs.  Makes the LadyBug disappear from the
           screen.



 6.9. HOME

           Takes no inputs.  Moves the LadyBug to the center of
           the screen and points her straight up.  If the pen is
           down the LadyBug will draw as she goes home.



 6.10. LEFT ANGLE   (ABBREVIATED LT)

           Takes one input, an angle.  If positive, it rotates the
           LadyBug that many degrees counterclockwise.  If
           negative, it rotates the LadyBug that many degrees
           clockwise.  The angle can exceed +359 or be smaller
           than -359; if it does, the angle is taken modulo 360.
           The maximum value is +32000 and the minumum value is
           -32000.








                                                           Page 16






                                                 Graphics Commands


           Example:

              left 90
              left -90

           Try:

              repeat 36 [left 10]



 6.11. NOCLIP

           Takes no inputs.  Tells LadyBug that an attempt to pass
           the edge of the screen will not cause the LadyBug's
           path to be clipped.  See WRAP and CLIP for more
           information.



 6.12. NODRAW   (ABBREVIATED ND)

           Takes no inputs.  Exits from graphics mode and enters
           text mode.  Clears the screen.  Places the cursor in
           the upper left corner.

           With two screens, the graphics screen is unchanged; the
           text screen is enabled for output commands.  See the
           chapter "The LadyBug Screens" on page 10 for more
           information about screens.



 6.13. NOWRAP

           Takes no inputs.  Tells Ladybug that an attempt to pass
           the edge of the screen will not cause the LadyBug to
           wrap around to the other side.  See WRAP and CLIP for
           more information.



 6.14. NOWINDOW

           Same as NOCLIP in this chapter.











                                                           Page 17






                                                 Graphics Commands


 6.15. PAINT PAINTCOLOR BORDERCOLOR

           Paint the area under and around the LadyBug with the
           painting color.  Painting is done in each direction
           until the border color is reached (or the edge is
           reached).

           If the border color is the same as the pen color, and
           the pen is down, the dot under the pen acts like a
           border and no painting occurs.  To be safe, lift the
           pen and move forward a slight amount.

           Paint colors and border colors are the same as pen
           colors; see PENCOLOR for information about colors.



 6.16. PALETTE PALETTENUMBER

           Takes one input, a zero or a one.  Sets the palette
           number.  A palette is a set of colors from which the
           allowable pen colors and painting colors are selected.
           There are two palettes with fixed colors.  See PENCOLOR
           for information on the colors in each palette.



 6.17. PENCOLOR COLOR   (ABBREVIATED PC)

           Takes one input, a number from 0 to 3.  The number is
           the color of the lines that the LadyBug will draw.  The
           colors are:

                       --- Palette ---
              COLOR       0       1
                1       Green   Cyan
                2       Red     Magenta
                3       Brown   White

           A color of zero is the same color as the background.
           (See the BACKGROUND command.)  Until you select a
           background, Ladybug uses a black background.

           Until you select a pen color, LadyBug uses color 3.

           Palettes are selected with the PALETTE command; until
           you select a palette, Ladybug uses palette one.

           Example:

              pencolor 2





                                                           Page 18






                                                 Graphics Commands


 6.18. PENDOWN   (ABBREVIATED PD)

           Takes no inputs.  When the pen is down, the LadyBug
           draws when she moves.



 6.19. PENUP   (ABBREVIATED PU)

           Takes no inputs.  When the pen is up the LadyBug does
           not draw when she moves.

           Example:

              penup
              forward 20
              pendown



 6.20. RIGHT ANGLE   (ABBREVIATED RT)

           Takes one input, an angle.  If positive, it rotates the
           LadyBug that many degrees clockwise.  If negative, it
           rotates the LadyBug that many degrees counterclockwise.
           The angle can exceed +359 or be smaller than -359; if
           it does, the angle is taken modulo 360.  The maximum
           value is +32000 and the minimum value is -32000.

           Example:

              right 47

           Try:

              repeat 10 [right 10 left 10]



 6.21. SETHEADING ANGLE   (ABBREVIATED SETH)

           Takes one input, an angle from -32000 to +32000.  The
           angle is taken modulo 360 so that it ranges from -359
           to +359.  The LadyBug is rotated so that it points in
           the direction given.  An angle of zero is straight up
           and increasing numbers are clockwise.

           Examples:

              setheading 45
              seth -90





                                                           Page 19






                                                 Graphics Commands


 6.22. SETBG COLOR

           Same as BACKGROUND in this chapter.



 6.23. SETPAL PALETTE

           Same as PALETTE in this chapter.



 6.24. SETPC COLOR

           Same as PENCOLOR in this chapter.



 6.25. SETSCRUNCH N   (ALSO: .SETSCRUNCH)

           Adjust the aspect ratio of screen drawings.  Initially
           it is 1.0 but can be set to any value from 0.1 to 10.
           The value is used to adjust the distance actually moved
           left-to-right relative to that requested.

           For example, with a value of 1.0, a FORWARD 10 moves
           the same distance left-and-right as up-and-down.  With
           a value of 0.8, a FORWARD 10 would move only 8 units
           left-or-right.

           Scrunch is necessary since different displays and
           printers do not have the same number of dots per inch
           in each direction.

           You may need to experiment with SETSCRUNCH in order to
           find the best value for your screen and printer.  (You
           may need to run with values which distort pictures on
           your screen in order to have printed pictures look
           right.)  Once you have found a value you like, you
           might want to put it into your PROFILE.BUG file.



 6.26. SETX XCOORD

           Takes one input, an x coordinate.  Positions the
           LadyBug at the position, drawing a line if the pen is
           down.








                                                           Page 20






                                                 Graphics Commands


 6.27. SETXY XCOORD YCOORD

           Takes two inputs, x and y coordinates.  Positions the
           LadyBug at the new position, drawing a line if the pen
           is down.

           Examples:

              setxy 0 0
              setxy  ( :a + 10 )  ( :b + 1 )



 6.28. SETY YCOORD

           Takes one input, an y coordinate.  Positions the
           LadyBug at the position, drawing a line if the pen is
           down.

           Try:

              to xy
              setx  250 - random 500
              sety  150 - random 300
              xy
              end
              xy



 6.29. SHOWBUG   (ABBREVIATED SB)

           Takes no inputs.  Makes the LadyBug appear on the
           screen.  May also be written SHOWTURTLE (abbreviated
           ST).



 6.30. SHOWTURTLE   (ABBREVIATED ST)

           Takes no inputs.  Makes the LadyBug appear on the
           screen.














                                                           Page 21






                                                 Graphics Commands


 6.31. WINDOW

           Same as CLIP in this chapter.



 6.32. WRAP

           Takes no inputs.  Causes the LadyBug to "wrap around"
           when it is moved past an edge.  For example, a path
           that goes off the top of the screen will continue at
           the bottom of the screen.

           This is the default condition.  The NOWRAP, CLIP, and
           NOCLIP statements also affect what happens when the
           LadyBug tries to go off of the edge.

           Try:

              wrap
              draw
              poly 200 170

           If neither WRAP nor CLIP is in effect, the LadyBug
           bumps into the edge of the screen.  Drawings will be
           distorted.

           Try:

              nowrap
              noclip
              draw
              penup fd 100 pendown
              poly 150 170

           WRAP is slowest, CLIP the next fastest, and NOWRAP with
           NOCLIP is faster still.  The performance effects are
           not major but are measurable.


















                                                           Page 22









 7. SOUNDS


 This section describes Ladybug commands for making sounds with
 the PC speaker.



 7.1. BEEP

           Play one short note on the speaker.



 7.2. PLAY STRING

           Takes one input, a string.  Play a series of notes on
           the speaker.

           This sections describes only a part of the PLAY
           command.  The appendix "The Play Command" on page 62
           describes PLAY completely.

           The PLAY statement is the word "PLAY" followed by a
           string which contains special music commands.  These
           commands define notes to play, or tell PLAY how to play
           the notes.

           Note: Spaces and capitalization in the PLAY statement
           are optional.


           A TO G WITH OPTIONAL '#', '+', OR '-'

           Play the note given.  Append a # or + if the note is a
           sharp or a - if it is a flat.


           L N

           Set the default length of all notes which follow.  For
           example, L1 means that all notes are whole notes, L2
           means half notes, and L4 means quarter notes.  The
           default is L4.


           O N

           Set octave n as the current octave.  All notes given as
           letters are in this octave.  The default octave is 4.
           The value of n may be 0 through 7.

           An octave has the notes C, D, E, F, G, H, A and B in
           it, in that order.  The octave does NOT start with the


                                                           Page 23






                                                            Sounds


           note A.
           P N

           Pause for n time units.  The meaning of the value of n
           is the same as in the L command.  The value of n may
           range from 1 to 64.

           Examples:

              play "ggga
              play "l4abcde
              play "'L4 abc L8 abc'

           Try:

              load "ludwig
              ludwig



 7.3. TONE FREQUENCY N

           Takes two inputs, a frequency and a time.  Produces a
           sound with the given frequency and for "n" clock ticks.
           The clock ticks 18.2 times per second.

           Examples:

              tone 2000 20



























                                                           Page 24









 8. INPUT AND OUTPUT


 This chapter describes statements which write data, or clear the
 input buffer.  Additional words are described in the chapter
 "Numbers and Computations" which starts on page 44.  These words
 include:

    STICK n          Joystick position
    PADDLE n         Joystick position
    PADDLEBUTTON n   Joystick button pushed?
    RC? and KEYP     Anything already typed?
    READCHARACTER    Read a character
    READCHAR         Read a character
    RC               Read a character
    REQUEST          Read a line of characters
    RQ               Read a line of characters
    STICKBUTTON n    Joystick button pushed?



 8.1. CLEARINPUT

           Takes no inputs.  Clears the input buffer of text typed
           but not yet read.



 8.2. PRINT WORD   (ABBREVIATED PR)

           Takes one input which it prints on the current output
           device.

           In graphics mode the line appears near the bottom of
           the screen and replaces any previously printed line.

           In text mode the line is printed below any other line,
           with the screen scrolling if necessary, and the cursor
           moves to the next line.



 8.3. PRINT1 WORD   (ABBREVIATED PR1)

           Takes one input which it prints on the current output
           device.  Leaves the cursor on the same line.
           Equivalent to TYPE in this chapter.

           In graphics mode the line appears near the bottom of
           the screen and replaces any previously printed line.
           Several PRINT1 commands in a row add to the same line.

           In text mode the line is printed at the current cursor
           position.  The cursor moves to the next line with the


                                                           Page 25






                                                  Input and Output


           screen scrolling if necessary.



 8.4. TYPE WORD

           Takes one input which it prints on the current output
           device.  Leaves the cursor on the same line.
           Equivalent to PRINT1 in this chapter.

           In graphics mode the line appears near the bottom of
           the screen and replaces any previously printed line.
           Several PRINT1 commands in a row add to the same line.

           In text mode the line is printed at the current cursor
           position.  The cursor moves to the next line with the
           screen scrolling if necessary.







































                                                           Page 26









 9. TEXT MODE


 This chapter describes statements which control the screen in
 text mode.  If these commands are given while in graphics mode,
 then text mode is entered.

 Text mode is also entered with the NODRAW command which is
 described in the chapter "Graphics Commands" which starts on page
 .

 The PRINT, PRINT1, and TYPE commands described in the previous
 chapter have special actions in text mode.



 9.1. CLEARTEXT   (ABBREVIATED CT)

           Takes no inputs.  Clears the text screen.  Moves the
           cursor to the top left corner.  Exits from graphics
           mode and enters text mode.



 9.2. CURSOR COLUMN ROW

           Takes two inputs which are a column and row position.
           The cursor is positioned at that place on the text
           screen.  The allowed values of the numbers depend upon
           which screen size is in use.

           The column may be in the range 1 to 40 (or 1 to 80
           depending upon the number of text columns) and the row
           may be 1 to 25.

           Example:

              to showmenu
              cursor  1  1  type "'Select from one of these:'
              cursor  5  4  type "'1 - Print the data'
              cursor  5  6  type "'2 - Erase the data'
              cursor  5  8  type "'3 - Plot the data'
              cursor  5 10  type "'4 - Save the data'
              end












                                                           Page 27






                                                         Text Mode


 9.3. SETWIDTH COLUMNS

           Same as TEXTCOLUMNS in this chapter.



 9.4. TEXTCOLUMNS COLUMNS   (ABBREVIATED TCOLS)

           Takes one input, either the number 40 or the number 80.
           Sets the screen width for text mode on the graphics
           monitor.  If the text screen is on the Monochrome
           display it always has a width of 80 and the value
           specified on this command is ignored.  The command is
           valid anytime but it takes effect only when in text
           mode and only when text mode is displayed on the
           graphics device.








































                                                           Page 28









 10. CONTROL COMMANDS


 This chapter describes commands which are used to define
 variables and procedures.



 10.1. EDIT PROCNAME ...   (ABBREVIATED ED)

           Takes a variable number of inputs.  Enters the full
           screen editor to edit the procedures.  The chapter
           "Introduction to the LadyBug Editor" on page 54
           describes this command and how to use the editor.

           Since the EDIT command takes a variable number of
           inputs, other commands cannot be on the same line
           behind it.

           Examples:

              edit poly
              ed poly polyspi square



 10.2. EDIT ALL

           Edit all procedures at one time.



 10.3. END

           In the full screen editor, END marks the end of a
           procedure which is entered from the editor.  It may be
           omitted from the last procedure but must be present if
           there is more than one procedure in the editors space.

           Following a TO command, END marks the end of the
           procedure begin defined.  It must be given and it must
           be on a line by itself.














                                                           Page 29






                                                  Control Commands


 10.4. ERROR MESSAGE

           Takes one input, a string.  Issues an error message
           with the string as the text and then terminates the
           currently active procedure set.  (See the chapter
           "Running and Debugging Procedures" on page 41.)

           Example:

              to move :d
              if :d > 100 [error "'Too far to move']
              fd :d
              end



 10.5. FOREVER LIST

           See chapter "Workspaces with Tools" on page 52.



 10.6. GOODBYE   (ABBREVIATED BYE)

           Exit to DOS from LadyBug.



 10.7. IF CONDITION THEN ACTION

           Test the condition.  If it is "true", then perform the
           action.  The action consists of all of the words
           remaining on the line.

           The condition is a word or expression which returns
           "true" or "false".

           The action is one or more LadyBug commands excepting an
           IF command with an ELSE clause.

           Example:

              if :x > 0 then fd 100

              if :ready then fd 50 rt 45 fd 100 rt 45 fd 50

           Also see the TEST command.









                                                           Page 30






                                                  Control Commands


 10.8. IF CONDITION [ACTION]

           Test the condition.  If it is "true", then perform the
           action (which is a list).  The action consists of the
           words in the list.

           The condition is a word or expression which returns
           "true" or "false".

           The action is one or more LadyBug commands including
           other IF commands.

           Examples:

              if :x > 0 [fd 100]

              if :ready [fd 50  rt 45  fd 100  rt 45  fd 50]

              make "alist [fd 10  rt 90  fd 90 rt 10]
              if :a > :b  :alist

           Also see the TEST command.



 10.9. IF CONDITION THEN ACTION1 ELSE ACTION2

           Test the condition.  If the result is "true", then
           perform action1; if it is "false", then perform
           action2.  Action1 consists of the words between the
           THEN and the ELSE.  Action2 consists of the words
           following the ELSE.  Neither action can be an IF/THEN
           or an IF/THEN/ELSE command.

           The condition is a word or expression which returns
           "true" or "false".

           The actions are one or more LadyBug commands.

           Example:

              if :x > 0 then fd 100 else fd 50

              if :ready then fd 50 rt 45 else bk 20 lt 10

           Also see the TEST command.










                                                           Page 31






                                                  Control Commands


 10.10. IF CONDITION [ACTION1] [ACTION2]

           Test the condition.  If it is "true", then perform
           action1; if it is "false", then perform action2.  The
           actions consist of the words in the lists.  The actions
           can contain other IF commands.

           The condition is a word or expression which returns
           "true" or "false".

           The actions are one or more LadyBug commands.

           Example:

              if :x > 0  [fd 100]  [fd 50]

              if :ready  [fd 50 rt 45]  [bk 20 lt 10]

           Also see the TEST command.



 10.11. IFFALSE LIST

           Takes one input, a list.  Tests the condition set by
           the most recently executed TEST command.  If it was
           "false" then the list is executed.

           Example:

              test :a > 7
              iffalse [fd 5 rt 5]



 10.12. IFTRUE LIST

           Takes one input, a list.  Tests the condition set by
           the most recently executed TEST command.  If it was
           "true" then the list is executed.

           Example:

              test :a > 7
              iftrue [fd 5]











                                                           Page 32






                                                  Control Commands


 10.13. LOCAL VARIABLENAME

           Defines a variable as being local to the current
           procedure.  It is available to any procedures which are
           called from the procedure in which it is defined unless
           they too make the name local or have an input variable
           with the same name.

           The variable has a null (empty) value until some value
           is assigned with the MAKE command.  See the MAKE
           command for more information about how LadyBug searches
           for variables.

           The LOCAL command should always be used in procedures
           which use variables for 'personal' reasons, such as
           temporarily holding the results of some calculation.

           Example:

              local "saveit

           A longer example:

              to a
              make "fred 1     <--- sets variable 'fred' to 1
              print :fred      <--- prints the value '1'
              b                <--- calls procedure 'b'
              print :fred      <--- prints the value '2'
              end

              to b
              make "fred 2     <--- sets same 'fred' as in 'a'
              local "fred      <--- makes a new local 'fred'
              make "fred 3     <--- sets the new 'fred' to 3
              print :fred      <--- prints the value '3'
              c                <--- call procedure 'c'
              end              <--- returns to procedure 'a'

              to c
              print :fred      <--- prints the value '3'
              end

           If "a" is invoked, the four values printed are 1, 3, 3,
           and 2 in that order.  After "a" is through, the
           variable "fred" still has the value 2.











                                                           Page 33






                                                  Control Commands


 10.14. MAKE "VARIABLENAME VALUE

           Takes two inputs, a word which will be a variable name,
           and a value.  The value may be an expression, a list,
           or a string.  MAKE assigns the value to a variable with
           the name given.  The value may be referenced by using
           the variable name with a colon on the front.

           If there already is a variable with the name given, the
           value replaces its current value.  If there is not
           already such a variable, one is created and given the
           value.

           Examples:

              make "a 7
              make "b 3 * :a
              make "c ( :a / :b ) + 2

           NOTE:  At any time that LadyBug is looking for a
           variable, the variables created by the current
           procedure are examined first.  If one with the needed
           name is not found, LadyBug then looks at variables
           created by the procedure which called the current one.
           If it has such a variable, it is used.  If not, then
           variables in the procedure that called that one are
           examined, etc.  Finally, variables which are not a part
           of any procedure but which are a part of the workspace
           are examined.  If no variable is found, then MAKE
           creates a new variable.

           Variables CREATED by MAKE are global.  That is, they
           will still exist after all active procedures terminate
           and will be saved when the workspace is saved.

           See the LOCAL command for information about another way
           to create variables and for information about the scope
           of variables in procedures which call one another.



 10.15. OUTPUT VALUE   (ABBREVIATED OP)

           Takes one input.  Causes the current procedure to stop.
           The value is output to the calling procedure.

           Examples:

              output 2
              output ( :a + 4 ) / 3
              op [2 3 4]





                                                           Page 34






                                                  Control Commands


 10.16. RANDOMIZE NUMBER

           Takes one input, an integer.  Sets the "seed" of the
           random number generator to this value.  Each time the
           same seed is used, successive calls to RANDOM will
           return the same sequence of random numbers.

           Examples:

              randomize 2127
              randomize :seed + 1173



 10.17. REPEAT NUMBER LIST

           Takes two inputs, a number and a list.  RUNs the
           commands in the list "number" times.

           Examples:

              repeat 4 [forward 100 right 90]
              repeat :n :alist

           Try:

              repeat 5 [fd 100 rt 144]
              repeat 36 [fd 10 rt 10]



 10.18. RUN LIST

           Takes one input, a list.  Executes the list as if the
           body were typed as a command line.

           Example:

              run [fd 10  rt 5]

           Example:

              make  "b  [fd 10  rt 5]
              run  :b












                                                           Page 35






                                                  Control Commands


 10.19. STOP

           Takes no inputs.  Causes the current procedure to stop
           and return control to the procedure which called it, if
           any, else to the command prompt.  No value is output.



 10.20. TEST CONDITION

           Takes one input, a condition.  The condition is a word
           or expression which returns "true" or "false".  The
           condition is evaluated and the result is remembered
           until changed by another TEST command.  The result can
           be tested by the IFTRUE and IFFALSE commands.

           Example:

              test
              iftrue [fd 10 rt 90]



 10.21. TOPLEVEL

           Takes no inputs.  Stops all active commands, procedures
           and PAUSEs.  Returns to the command prompt.



 10.22. WAIT TIME

           See chapter "Workspaces With Tools" on page 52.



 10.23. WHILE CONDITION LIST

           See chapter "Workspaces With Tools" on page 52.

















                                                           Page 36









 11. MANAGING THE WORKSPACE


 This chapter describes statements which are used to control and
 manage the workspace.



 11.1. CATALOG   (ABBREVIATED CAT)

           Takes no inputs.  Prints the names of files contained
           on the current disk.  In graphics mode, the current
           screen is cleared and the catalog is displayed as if
           temporarily in text mode.



 11.2. CLEARWS

           Takes no inputs.  Clears all variables and procedures
           from the workspace.



 11.3. DEFINE "NAME LIST

           Takes two inputs which define a procedure.  The first
           is the name of the procedure and the second is the body
           of the procedure.  If a procedure already exists with
           the name given, the old one is deleted.

           The body of the procedure is a list of lists.  Each
           sublist is one line of the procedure.  The first
           sublist contains the names of the inputs to the
           procedure.

           Example:

              to tri :s
                 repeat 3 [fd :s rt 120]
              end

              can be defined as:

              define "tri [[:s][repeat 3 [fd :s rt 120]]]

           If there are no inputs then the first sublist is empty:

           Example:

              to circ
              fd 10
              rt 10
              circ


                                                           Page 37






                                            Managing the Workspace


              end

           can be defined as:

              define "circ [[][fd 10][rt 10][circ]]



 11.4. EDIT PROCNAME ...

           Takes a variable number of inputs.  Enters the full
           screen editor to edit the procedures.  The chapter
           "Introduction to the LadyBug Editor" on page 54
           describes this command and how to use the editor.

           Examples:

              edit poly
              ed poly polyspi square



 11.5. EDIT ALL

           Edit all procedures at one time.



 11.6. ERASE PROCEDURENAME

           Delete the procedure named.

           Example:

              erase "poly

           NOTE:  ERASE can be used to delete a procedure from
           within itself without disturbing the currently
           executing copy of the procedure.



 11.7. ERASE ALL

           Delete all procedures.











                                                           Page 38






                                            Managing the Workspace


 11.8. ERASEFILE FILENAME

           Erase the disk file named.

           Example:

              erasefile "b:crawlie.bug



 11.9. ERNAME VARIABLENAME

           Delete the variable named.  If there are more than one
           with the same name, ERNAME deletes the most recently
           defined variable.

           Example:

              ername "bart



 11.10. ERNAME ALL

           Delete all variables.



 11.11. LOAD FILENAME

           Same as READ in this chapter.



 11.12. PRINTOUT NAME   (ABBREVIATED PO)

           Print the value of the variable and/or definition of
           the procedure with the name given.

           Example:

              printout "elephant














                                                           Page 39






                                            Managing the Workspace


 11.13. READ FILENAME

           Load the named workspace and add its variables and
           procedures to the workspace.  If no file extension is
           given, .BUG is used.

           Examples:

              read "polyspi
              read "b:circ.lgo

           See the chapter "Hints on Using LadyBug" on page 57 for
           more information about uses of READ.



 11.14. SAVE FILENAME

           Save the current workspace in the file named.  If no
           file extension is given, the default of BUG is used.

           Example:

              save "bobby
              save "b:whoops.2

           The appendix "Format and Contents of Saved Workspaces"
           on page  describes the format of the workspace as it is
           saved on disk.



 11.15. TO PROCNAME INPUTS...

           Takes one or more inputs.  The first is the name of a
           procedure which is to be defined.  If a procedure with
           the same name already exists the old definition is
           deleted.

           The remaining inputs are the names of inputs to the new
           procedure.

           Lines read after the TO command become lines in the new
           procedure.  A line containing the word END alone, ends
           the definition of the new procedure.

           Example:

              to poly :dist :angle
              fd :dist
              rt :angle
              poly :dist :angle
              end



                                                           Page 40









 12. RUNNING AND DEBUGGING PROCEDURES


 This chapter describes how to run procedures and describes some
 commands which help debug them.



 12.1. RUNNING PROCEDURES

 Procedures are groups of commands which are saved under a name
 for later execution.  Procedures are created with the LadyBug
 editor, with the TO command, or with the DEFINE command.

 A procedure is run by giving its name instead of the name of a
 command.

 Example:

    to moveup
    forward 20
    end

 This defines a procedure named MOVEUP.  The procedure can be run
 by typing its name, MOVEUP.  In effect, procedures are new
 commands and the term "command" often is used to refer to
 procedures as well as primitive, or builtin, commands.

 Procedures can invoke, or call, other procedures.  When several
 procedures are active at one time, the group is often called a
 "nest" of procedures or a "nested group" or procedures.

 Inputs to procedures can be any value or expression with one
 exception: an input must not refer to another procedure.  That
 is, you cannot run one procedure in order to directly define an
 input for another.



 12.2. PAUSING PROCEDURES

 Procedures, as well as commands like REPEAT which have a list of
 other commands in them, can be temporarily stopped with the pause
 key, F5, or with a PAUSE command imbedded in them.

 When a procedure has been paused, LadyBug accepts commands and
 will execute any command.  It indicates that some other command
 has been paused by printing the word "pause" instead of a
 question mark for a command prompt.

 It is possible to run other procedures while a procedure is
 paused.  The new procedure or procedure nest can itself be
 paused.  Then yet another procedure can be run, and that one
 paused, and so on subject only to the restriction of 40 active


                                                           Page 41






                                  Running and Debugging Procedures


 procedures, repeat commands, pauses, loads, and active expression
 evaluations at one time.

 The group or nest of procedures that is suspended by a PAUSE or
 by F5 is called a "Procedure set".  The F1 key terminates only
 the currently active procedure set.  Thus, if you use F1 to
 terminate a procedure run while another is paused, only it will
 be terminated.  The TOPLEVEL command terminates all procedure
 sets.  (The .STACK command described in the appendix "Hackers
 Only" on page 74 will display the stack of active procedures,
 expressions, pauses, etc.)



 12.3. EDITING ACTIVE PROCEDURES

 It is possible to edit a procedure which is active.  Either the
 EDIT command can be in a procedure or the EDIT command can be
 given after the running procedure has been paused.

 However, the changes made to the procedure do not affect any
 currently active execution of that procedure.



 12.4. CONTINUE    (ABBREVIATED CO)

           The continue command resumes execution of a paused
           procedure set.



 12.5. NOTRACE

           Turn off tracing.  When tracing is active the F9 key
           will also turn off tracing.



 12.6. PAUSE

           Pause the current nest of procedures.  The F5 key will
           also pause the current procedure nest.













                                                           Page 42






                                  Running and Debugging Procedures


 12.7. TOPLEVEL

           Terminate all active procedures in all active procedure
           sets, and all active commands.  Return to the top level
           command prompt.



 12.8. TRACE

           Turn on tracing.  When trace is on, each command that
           is executed from any source, procedure or command
           prompt, is shown and LadyBug pauses for a key to be
           pressed.

           F9 also turns on and off tracing.



 12.9. ;  (COMMENT)

           Any line which starts with a semicolon is a comment
           line.  The contents of the line are ignored.

































                                                           Page 43









 13. NUMBERS AND COMPUTATIONS


 This section describes numbers and how to compute with them.



 13.1. NUMBERS

 Numeric values come in two types: integer, and floating point.

 Integer numbers have only whole number values.  These values must
 be in the range of -32768 to 32767.

 Floating point numbers have whole number and fractional values
 and an optional exponent.  Their value in the computer may range
 from 2.9x10**(-39) to 1.7x10**38 (where the 10**(-39) means
 "times ten to the -39 power" and 10**38 means "times ten to the
 38th power".)

 When you enter floating point numbers into the computer, they
 must have one of the forms, for example:

     1.   .2   1.2   1E2   1.E2   .2E2   1.2E2   1.2E-2   1.2e2

 Each may also have a sign.  The "e" or "E" separates the number
 from its power of ten.



 13.2. NUMERIC AND MATHEMATICAL VALUES

 ABS number
     Returns the absolute value of the number.

 ARCTAN tangent
     Returns the angle which has the tangent given.

 ASC string
     Takes one input, a string or word.  Returns a number from 0
     to 255 which is the ASCII code for the first character of the
     string or word.

 BACKGROUND   (Abbreviated BG)
     The background color.

 CHAR expression
     Takes one input, a number from 0 to 255.  Returns the ASCII
     character which corresponds to that number.

 COS angle
     Returns the cosine of the angle in degrees.




                                                           Page 44






                                          Numbers and Computations


 EXP power
     Returns the mathematical quantity 'e' raised to the power
     given.

 HEADING
     The (integer) angle that the LadyBug is currently facing.
     The value ranges from -359 to 359.

 INTEGER number
     Returns the integer which is equal to or just smaller than
     the number given.  If the number is negative the result is
     smaller when it is "further away" from zero.

 LOG number
     Returns the logarithm of the number taken to base 10.

 NUMBER? word
     Takes one input.  Returns "true" if the word represents a
     number and "false" if it does not.

 PALETTE
     The palette number.

 PENCOLOR  (Abbreviated PC)
     The color of the pen.

 RANDOM range
     Returns a random number in the range 0 to 'range'.  (See the
     RANDOMIZE statement for more information.)

 RUN list/word/string
     Takes one input, a list, string, or word.  RUNs the input and
     returns it's output.

     Example:

        make "x [2 + 3]
        print run :x

     The example prints the number "5".

 SCRUNCH
     The value of the aspect ratio adjustment.  See the SETSCRUNCH
     command.

 SENTENCE word/list word/list    (Abbreviated SE)
     Takes two inputs, words or lists.  Forms a list of the words
     or the components of the lists, and returns the new list.








                                                           Page 45






                                          Numbers and Computations


     Examples:

        make "x sentence [a b] [c d]
        make "x sentence joe [frank bob]

 SIGN number
     Returns +1 if number is positive, 0 if number is zero, and -1
     if number if negative.

 SIN angle
     Returns the sine of the angle in degrees.

 SQRT number
     Returns the square root of the number.

 TAN angle
     Returns the tangent of the angle in degrees.

 THING word
     Takes one input, a word which is the name of a variable.
     Returns the value of that variable.  The following are
     exactly equivalent:

     Example:

        :elephant
        thing "elephant

     Example:

        make "a "apple
        make "b "a
        print thing :b

     prints "apple".

 WORD word1 word2
     Takes two inputs and combines them into one word.

     Example:

        make "x word "a "b

     The variable x is set to "ab".

 XCOR
     The current x coordinate of the LadyBug.

 YCOR
     The current y coordinate of the LadyBug.






                                                           Page 46






                                          Numbers and Computations


 Examples:

    GIVEN                 PRINTS
    print abs -7          7
    print integer 7.7     7
    print integer -3.3    -4
    print log 100         10
    print random 10       2.32    (example result)
    print sign 4          1
    print sign -4         -1
    print sqrt 4          2



 13.3. OTHER WORDS

 The following words return values.  Some take one input.

 STICK n    (or PADDLE n)
     Takes a number from 0 to 3 which corresponds to one of four
     joysticks and returns a number from 0 to 255 which represents
     it's setting.  The range of values will depend upon the
     particular joystick used.

 STICKBUTTON n    (or PADDLEBUTTON n)
     Takes a number from 0 to 3 which corresponds to one of four
     joysticks and returns TRUE or FALSE depending upon whether or
     not the button on the particular joystick has been pressed
     since the last time PADDLEBUTTON was used.

 RC?  or  KEYP
     Takes no inputs.  Outputs TRUE if a keyboard character is
     pending, that is, if the character input buffer is not empty.
     Otherwise it outputs FALSE.

 READCHARACTER   (Abbreviated READCHAR or RC)
     Takes no inputs.  Outputs the least recent character in the
     character buffer, or waits for a keyboard character to be
     typed if the buffer is empty.

 REQUEST   (Abbreviated RQ)
     Takes no inputs.  Waits for a keyboard line to be typed and
     outputs the line.  The line is terminated by pressing the
     enter key.  Until the enter key is pressed, the backspace key
     will move back over and delete characters that have been
     typed in response to REQUEST, the back arrow key will move
     back over and allow insertions and deletions with the Ins and
     Del keys, and the ESC key will delete everything typed so
     far.

 PENUP?  and  PENDOWN?
     Neither takes an input.  Both return either "true" or "false"
     depending upon whether the pen is up or down.



                                                           Page 47






                                          Numbers and Computations


 SHOWING?  and  HIDDEN?
     Neither takes an input.  Both return either "true" or "false"
     depending upon whether the LadyBug is showing or hidden.



 13.4. EXPRESSIONS RESULTING IN NUMBERS

 Numbers can be combined into expressions.  Expressions are
 evaluated from left to right with no operator hierarchy.
 Parentheses may be used to group operations which should be
 performed first.

 Expressions are taken, word by word, with only blanks separating
 words.  Operators, numbers, and parentheses must be separated by
 blanks to be properly recognized.  For example, this is invalid:

    FORWARD 3+4

 but this is valid:

    FORWARD 3 + 4

 Expressions may occur anywhere that LadyBug is looking for a
 number or a truth value.  Even though an expression may have many
 words in it, it is still considered as one input.

 Unless noted, operations on integers result in integers and
 operations on floating point numbers result in floating point
 numbers.  When one operand of two given for an operator is
 integer, it is converted to floating point.

 The operators taking two values are:

 +     (plus)
     Returns the sum of two numbers.

 -     (minus)
     Returns the difference of two numbers.

 *     (times)
     Returns the product of two numbers.

 /     (divide)
     Returns the result of dividing the first number by the second
     number.  If both are integers, they are converted to floating
     point before the divide is done.

 ^     (power)
     Returns the first number raised to the power given by the
     second number.  The second number must be an integer or
     LadyBug signals an error.




                                                           Page 48






                                          Numbers and Computations


 \     (mod)
     Returns the remainder from dividing the first number by the
     second number.  If either is floating point, it is rounded to
     an integer first.

 Examples:

    forward 3 * ( 2 + 5 )
    right 5 * :x
    right ( 5 * :x )
    make "x  :x + 1
    print integer 100 * sin 4 + :angle
    print integer ( 100 * sin ( 4 + :angle ) )

 The last two lines are evaluated the same way.



 13.5. EXPRESSIONS RESULTING IN TRUE OR FALSE

 Relational expressions result in "true" or "false".  They have
 the following form:

    value1 op value2

 where the values are numbers, variables, or expressions and "op"
 is one of the following relational operators:

 <
     Returns 'true' if value1 is less than value2.

 <=
     Returns 'true' if value1 is less than or equal to value2.

 >
     Returns 'true' if value1 is greater than value2.

 >=
     Returns 'true' if value1 is greater than or equal to value2.

 <>
     Returns 'true' if value1 is not equal to value2.

 =
     Returns 'true' if value1 is equal to value2.

 Conditionals can be combined with AND and OR.  See the chapter
 "Workspace With Tools" on page 52.

 In addition:






                                                           Page 49






                                          Numbers and Computations


 NOT value
     Returns "true" when the value is "false" and "false" when the
     value is "true".

 Examples:

    GIVEN                 PRINTS
    print 2 < 3           true
    print 3 > 2           false
    print 2 <= 3          true
    print 2 <> 3          true
    print not 2 < 3       false

 Examples:

    if :a + 2 > 17 [ ... ]
    test ( sin 2 * :b ) <= .5



 13.6. PROCEDURES

 Procedures can be invoked from within expressions and can return
 values.  When LadyBug finds a word in an expression it looks
 first to see if the word is a number.  If not, it looks to see if
 the word is one of the special words described in this chapter.
 If not, it looks to see if the word is the name of a procedure in
 the workspace.

 If the word is the name of a procedure, the procedure is invoked.
 The procedure must terminate with an OUTPUT command which
 specifies a value suitable for the context in which it was
 invoked.  (For example, if the procedure follows a plus sign, it
 would be expected to return a number.)

 Example:

    to inc :v
    return :v + 1
    end

    print 5 + v 6

 The procedure adds one to its input.  It is invoked in the PRINT
 command with an input of 6.  The returned value, a 7, is added to
 the 5 and a 12 is printed.

 LadyBug has the restriction that a procedure cannot be started
 when the inputs to another procedure are being evaluated.  The
 following, for example, is invalid:






                                                           Page 50






                                          Numbers and Computations


 Example:

    print 5 + v v 6

 If allowed, it would increment the 6 twice.



















































                                                           Page 51









 14. WORKSPACES WITH TOOLS


 This chapter describes procedures which are in the workspace
 named TOOLS.  An appendix describes other workspaces which
 contain example procedures.



 14.1. AND  T/F  T/F

           Takes two inputs, both expressions which evaluate to
           "true" or "false".  Returns "true" only if both inputs
           are "true".

           Example:

              print and :a < 2 :b > 4

           Example:

              if  and  :a > 3  :a < 10   [fd :a]



 14.2. FOREVER LIST

           Takes one input, a list.  RUNs the list over and over,
           forever.

           Example:

              forever [fd 1 rt 1]



 14.3. MAX VALUE1 VALUE2

           Takes, two inputs, both expressions which return some
           value.  Returns the largest of the two.



 14.4. MIN VALUE1 VALUE2

           Takes, two inputs, both expressions which return some
           value.  Returns the smallest of the two.









                                                           Page 52






                                             Workspaces With Tools


 14.5. OR  T/F  T/F

           Takes two inputs, both expressions which evaluate to
           "true" or "false".  Returns "true" if either input is
           "true".

           Example:

              if  or  :a > 3  :a < 10   [fd :a]



 14.6. WAIT TIME

           Takes one input, a time in seconds.  LadyBug pauses for
           this length of time.



 14.7. WHILE [CONDITION] [COMMANDS]

           Takes two inputs, a condition and commands.  Each input
           is given as a list.  The condition is an expression
           which returns "true" or "false".  The condition is
           evaluated and, if true, the list of commands is RUN.
           The condition is again evaluated and the list RUN.
           This is repeated so long as the condition remains true.

           Example:

              while [heading < 200]  [fd 10 rt 10]



 14.8. XOR  T/F  T/F

           Takes two inputs, both expressions which evaluate to
           "true" or "false".  Returns "false" if both inputs are
           the same and "true" if different.

           Example:

              if  xor  :a > 3  :a < 10   [fd :a]













                                                           Page 53









 15. INTRODUCTION TO THE LADYBUG EDITOR


 This chapter describes the basics of using the LadyBug full
 screen editor.  The appendix "About the LadyBug Editor" on page
 59 describes additional features of the editor.



 15.1. ABOUT THE EDITOR

 The LadyBug Editor is a full screen editor for LadyBug
 procedures.  It displays one or more procedures totalling up to
 500 lines long and with lines up to 254 characters long.  It uses
 the IBM Monochrome Display or 40 or 80 column graphics display.

 The screen is a window onto the file.  The window can move up,
 down, left and right.  Lines which are longer than the screen are
 partly displayed.  If you insert data, characters seem to be lost
 off of the end of the line; they are not lost but are just no
 longer displayed.  Move the cursor off of the screen to the right
 and they will reappear as the window moves.

 If memory becomes nearly full, the LadyBug Editor tells you and
 lets you continue editing but won't let you add more lines.



 15.2. INVOKING THE EDITOR

 Command: EDIT procname1 ...   (Abbreviated ED)
      or: EDIT ALL

 Takes a variable number of inputs each of which is a procedure
 name or a vaiable name which has as a value a procedure name.
 Enters the full screen editor to edit the procedures.

 The procedures named are displayed, each ending with an END
 command.  If ALL is given, all procedures are edited.  Lines may
 be changed, added, deleted, or moved.  When multiple procedures
 are being edited, lines may be moved between procedures.

 If a procedure is deleted in the editor, or its name is changed,
 it is not deleted from the workspace.  Only those procedures
 which are still in the editors space when you terminate editing
 are moved back to the workspace.  New procedures created within
 the editor are added to the workspace when you edit from the
 editor.  Use the ERASE statement to delete procedures from the
 workspace.







                                                           Page 54






                                Introduction to the LadyBug Editor


 15.3. THE LADYBUG EDITOR KEYS

 The following list defines the meaning of each key.

 Backspace
      Backspace over and delete the previous character.

 Character keys, shifted and unshifted.
      Enter the character into the current line.  If in insert
      mode, put it at the cursor position and slide the characters
      under and to the right of the cursor to the right.  If in
      replace mode, replace the character under the cursor.

 Cursor keys (arrows on numeric keypad)
      Move the cursor up, down, left, or right one position.  If
      the cursor would move off of the screen in a direction in
      which there is more data, then scroll the screen one
      character in that direction.

 Del
      Delete the character under the cursor.  Slide the characters
      at its right to the left one position.

 End
      Position the cursor past the end of current line.

 Enter key
      Put a new line in the file and position the cursor at the
      front of it.

 F5
      Clear the current line and position the cursor at the left
      edge.

 F6
      Clear the current line under and to the right of the cursor.

 F7
      Quit editing.  Abandon the procedure(s) being edited.  (If
      any changes have been made, the editor asks before
      abandoning them.)

 F9
      End editing.  Save the procedure(s) being edited.

 Home
      Position the cursor in the first column of both the current
      file line and the screen.








                                                           Page 55






                                Introduction to the LadyBug Editor


 Ins
      Toggle between insert and replace modes.  The status line
      describes which is in effect.  The cursor also changes size.

 Pg Dn
      Scroll down 20 lines when the screen is 80 characters wide
      and 18 lines when 40 wide.

 Pg Up
      Scroll up 20 lines when the screen is 80 characters wide and
      18 lines when 40 wide.

 Shift-F8
      Delete the line at the cursor.  The cursor moves to the next
      line in the file.

 Tab
      Tab right to the beginning of the next word.  (Words are
      groups of characters separated by blanks.)





































                                                           Page 56









 16. HINTS ON USING LADYBUG


 This chapter contains several helpful hints about how to use
 LadyBug effectively.



 16.1. PRINTING THE SCREEN ON AN IBM OR EPSON PRINTER

 IBM printers must be either the Graphics Printer or the Matrix
 Printer with either the IBM Graphics upgrade or Epson GrafTrax
 upgrade.  Epson printers must have the GrafTrax feature.

 Under DOS 2.0 (or later systems) you must give the GRAPHICS
 command in DOS before running LadyBug.

 Under DOS 1.1 or 1.0 there is no way to print the graphics screen
 unless you have a GRAPHICS command distributed with the IBM
 Graphics printer for that version, or an equivalent.



 16.2. PRINTING THE SCREEN ON OTHER PRINTERS

 The manufacturers of many dot matrix printers provide software
 which will print the graphics screen.  Other routines are
 available through various PC clubs.



 16.3. THE READ COMMAND

 The READ command described on page 40 causes LadyBug to
 temporarily stop reading commands from the keyboard.  Commands
 are read instead from the file named.

 Any LadyBug command can be in the file.  However, there is no way
 to create a file from within LadyBug which contains arbitrary
 commands.  It is necessary to use a program called an "editor" to
 create the file.(5)

 The READ command can itself occur within a READ command.  And
 another READ in that one, and another read in that one.  The
 limit is four active READ commands.

 READ files can be created which contain long sequences of

 ____________________

 (5) An editor named FRED, which is distributed with LadyBug, will
 create such files.  FRED is very similar to the LadyBug editor.
 However any editor will do, including the EDLIN program which
 comes with DOS.


                                                           Page 57






                                            Hints On Using LadyBug


 commands to draw large pictures.  The commands are executed and
 discarded; they do not take space in the workspace unless they
 are MAKE, TO, or DEFINE commands.



 16.4. TAILORING LADYBUG: THE PROFILE

 When LadyBug starts up, it READs a workspace named PROFILE.BUG.
 This workspace file can be modified to contain any LadyBug
 commands.  When it is read, the commands will be executed.



 16.5. PERFORMANCE HINTS

 Major performance improvements:

 -   Hide the LadyBug using HB or function key F10.  Procedures
     may run as much as 3 times faster with the LadyBug hidden.

 -   Unwind procedures.  Of the following, POLYB is takes 70
     percent of the time of POLYA.

        to polya :d :a               to polyb :d :a
        fd :d  rt :a                 fd :d  rt :a
        poly :d :a                   fd :d  rt :a
        end                          poly :d :a
                                     end

 -   Repeat instead of recurse.  POLYC is twice as fast as POLYA.

        to polyc :d :a
        repeat 1000 [fd :d  rt :a]
        poly :d :a
        end

 Minor improvements:

 -   Specify NOCLIP and NOWRAP when there is no danger of needing
     CLIP or WRAP.

 -   Put multiple statements on a line.

 In any case, don't worry about these performance improvements
 until you have proven that you need them.  Premature use of them
 will simply complicate the creation process.









                                                           Page 58









 APPENDIX A. ABOUT THE LADYBUG EDITOR


 This appendix describes the LadyBug editor completely.  It
 repeats the introductory information given in the main part of
 the document.

 The LadyBug Editor is a full screen editor for LadyBug
 procedures.  It displays procedures or groups of procedures up to
 500 lines long and with lines up to 254 characters long.  It uses
 the IBM Monochrome Display or 40 or 80 column graphics display.

 The screen is a window onto the file.  The window can move up,
 down, left and right.  Lines which are longer than the screen are
 partly displayed.  If you insert data, characters seem to be lost
 off of the end of the line; they are not lost but are just no
 longer displayed.  Move the cursor off of the screen to the right
 and they will reappear as the window moves.

 If memory becomes nearly full while you are editing, the LadyBug
 Editor tells you and lets you continue editing but won't let you
 add more lines.



 A.1. THE LADYBUG EDITOR KEYS

 The following list defines the meaning of each key.  The term
 "current line" means the line the cursor is currently on.

 Alt-d
      Delete a marked area; see Alt-l for more information.

 Alt-j
      Join the next line onto the current one at its end.

 Alt-l
      Mark the current line or extend a group of marked lines.
      The first Alt-l marks a line and displays it in reverse
      video.  The second marks all lines from the first one
      through the second.  Further Alt-l keystrokes extend the
      marked area to the current line (or shrink it from the
      nearest edge).

      Marked areas may be copied, deleted, or unmarked.  See
      Alt-z, Alt-d, and Alt-u.

 Alt-s
      Split the current line into two parts at the cursor.  At
      column one this adds a new line before the current one.






                                                           Page 59






                                          About the LadyBug Editor


 Alt-u
      Unmark an area; see Alt-l.

 Alt-z
      Copy a marked area to just after the current line.  A marked
      area cannot be copied into itself.

 Backspace
      Backspace over and delete the previous character.

 Character keys, shifted or unshifted.
      Enter the character into the current line.  If in insert
      mode, put it at the cursor position and slide the characters
      under and to the right of the cursor to the right.  If in
      replace mode, replace the character under the cursor.

 Ctrl-End
      Position the cursor on the last line of the file.  Keep it
      in the same column.

 Ctrl-Home
      Position the cursor on the top line of the file.  Keep it in
      the same column

 Ctrl-Left
      Move the cursor to the left 40 positions.

 Ctrl-Pg Dn
      Position the cursor at the bottom edge of the screen (or on
      the last line of the file if encountered first).  The column
      position is unchanged.

 Ctrl-Right
      Move the cursor to the right 40 positions.

 Cursor keys (arrows on numeric keypad)
      Move the cursor up, down, left, or right one position.  If
      the cursor would move off of the screen in a direction in
      which there is more data, then scroll the screen one
      character in that direction.

 Del
      Delete the character under the cursor.  Slide characters at
      its right to the left one position.

 End
      Position the cursor past the end of current line.

 Enter key
      Put a new line in the file and position the cursor at the
      front of it.  (Also see Alt-s.)





                                                           Page 60






                                          About the LadyBug Editor


 F5
      Clear the current line and position the cursor at the left
      edge.

 F6
      Clear the current line under and to the right of the cursor.

 F7
      Quit editing.  If any procedure has been changed, you will
      be prompted for a 'y' before the LadyBug Editor really
      quits.

 F9
      Stop editing.  Re-enter LadyBug mode with the changed
      procedure(s).

 Home
      Position the cursor in the first column of both the current
      file line and the screen.

 Ins
      Toggle between insert and replace modes.  The status line
      describes which is in effect.

 Pg Dn
      Scroll down 20 lines when the screen is 80 columns wide and
      18 lines when it is 40 wide.

 Pg Up
      Scroll up 20 lines when the screen is 80 columns wide and 18
      lines when it is 40 wide.

 Shift-F4
      Undo a change to the current line.  Once the cursor is moved
      from the line the change cannot be undone with this key.

 Shift-F8
      Delete the line at the cursor.  The cursor moves to the next
      line in the file.

 Tab
      Tab right to the beginning of the next word.  (Words are
      groups of characters separated by blanks.)













                                                           Page 61









 APPENDIX B. THE PLAY COMMAND


 This appendix describes the PLAY command completely, repeating
 information contained in the summary in the main part of this
 document.

 The PLAY statement is the word "PLAY" followed by a string which
 contains special music commands.  These commands define notes to
 play, or tell PLAY how to play the notes.

 Note: Spaces and capitalization in the PLAY statement are
 optional.



 B.1. MUSIC COMMANDS


 A TO G WITH OPTIONAL '#', '+', OR '-'

 Play the note given.  Append a # or + if the note is a sharp or a
 - if it is a flat.


 LN

 Set the default length of all notes which follow.  For example,
 L1 means that all notes are whole notes, L2 means half notes, and
 L4 means quarter notes.  The default is L4.

 The value of n may vary from 1 to 64.  The actual note length is
 1/n.  That is, if n is 8 then the note has a length of 1/8.
 Unless changed by the T command, each quarter note lasts 1/2
 second.)

 The default length may be changed for any note by appending a
 different length to it.  For example, in

    PLAY "'L4 a b c8'

 the notes 'a' and 'b' will be played as quarter notes but 'c'
 will be an eighth note.


 MB

 Tell PLAY to play music in the background; that is, to start the
 music playing and to proceed to the next statement.  If LadyBug
 then finds another SOUND or PLAY statement, it pauses until the
 tune is complete.  Up to 32 notes (or rests) may be played in the
 background.  MB is NOT the default.

 Once you have given the MB command in one PLAY statement that all


                                                           Page 62






                                                  The PLAY Command


 further PLAY statements run in the background.


 MF

 Play music in the foreground; that is, wait for the music to
 complete before proceeding to the next statement.  This is the
 default.


 MN

 Play notes the "normal" length of time.  (MN means Music Normal.)
 This is defined as 7/8th of the time specified by the note
 length.  The other 1/8 of the time is silence.


 ML

 Play notes the full time specified by the note length.  (ML means
 Music Legato).  There is NO pause between notes.


 MS

 Play notes 3/4 of the time specified by the note length.  (MS
 means Music Staccato.)  The other 1/4 of the time it rests.


 N N

 Play note n.  The value of n may range from 0 to 84 with 0
 meaning a rest (no sound).  Note 1 is the C of octave zero.


 O N

 Set octave n as the current octave.  All notes given as letters
 are in this octave.  The default octave is 4.  The value of n may
 be 0 through 7.  For example, the following two commands are
 equivalent:

 PLAY "O0c
 PLAY "N1

 An octave has the notes C, D, E, F, G, H, A and B in it, in that
 order.  The octave does NOT start with the note A.

 The table below shows the frequencies for each note.  The values
 in octaves three and above have been rounded to integers.  The
 minus signs mean "flat".





                                                           Page 63






                                                  The PLAY Command


         ---------------- Octave ----------------
 Note     0     1      2      3    4    5     6
 ------  ----------------------------------------
 c       32.7  65.4   130.8  262  523* 1046  2093
 c# d-   34.6  69.3   138.6  277  554  1109  2217
 d       36.7  73.4   146.8  294  587  1175  2349
 d# e-   38.9  77.8   155.6  311  622  1244  2489
 e       41.2  82.4   164.8  330  659  1318  2637
 f       43.7  87.3   174.6  349  698  1397  2794
 f# g-   46.2  92.5   185.0  370  740  1480  2960
 g       49.0  98.0   196.0  392  784  1568  3136
 g# a-   51.9  103.8  207.7  415  831  1661  3322
 a       55    110    220    440  880  1760  3520
 a# b-   58.3  116.5  233.1  466  932  1865  3729
 b       61.7  123.5  246.9  494  988  1975  3951
         * - Middle C

          Frequencies for Seven Octaves


 P N

 Pause for n time units.  The meaning of the value of n is the
 same as in the L command.  The value of n may range from 1 to 64.


 T N

 Set the tempo.  The tempo is the number of quarter notes per
 minute The value of n may range from 32 to 255.  The default is
 120.

 This means that there are 120 quarter notes per minute or that
 each quarter note begins 1/2 second after the previous quarter
 note.


 A DOT (.)

 A dot, placed after a note, causes the note to be played 3/2 the
 time it would otherwise be played.  A second dot multiplies the
 length again by 3/2 giving a result of 9/4 the time of the
 original note.  Dots may also appear after the P and N commands.

 Note: There are two kinds of dotted notes in music; those with a
 dot BELOW the note which means staccato, and those with one or
 two dots AFTER the note which means to change the note timing.

 PLAY's dot convention differs from that used in normal music
 notation where the first dot after a note adds 1/2 of the note
 time, and a second dot adds 1/2 of 1/2 to the note time.  Thus a
 note with double dots would have a length of 7/4 of its original
 length rather than the 9/4 that PLAY has.



                                                           Page 64






                                                  The PLAY Command


 DEFAULTS

 The defaults given are what you get when LadyBug first starts up.
 However, if you change the default in one PLAY statement, it
 stays changed for further statements.



 B.2. EXAMPLES OF PLAY STATEMENTS

 This sections illustrates the use of the Play statement.  The
 workspace named SOUNDS contains all of the following examples of
 Play and additional ones.

 First, a space ship:

 Example:

    to ship1
       play "'L64 T255'
       repeat 10 [play "'n40 n42 n44 n46 n48 n50 n48 n46 n44 n42 n40']
    end

 Now, a clock ticking:

 Example:

    to clock :tics
       play "'L50 MB MS T255'
       repeat :tics [play "'N1 P1 N2 P1']
    end

 And now, a bird call:

 Example:

    to bird1
       play "'L64 MB ML T255 O4'
       play "'N64 N66 N68 N70 P64'
       play "'N66 N68 N70 N72 N74 N76 N78 P64'
       play "'N66 N68 N70 N72 P64'
       play "'N64 N66 N68 N70 P64'
       play "'N70 N72 N74 N76 N78 N80 P64'
       play "'N66 N68 N70 N72 P64'
    end











                                                           Page 65









 APPENDIX C. A GUIDE TO EXAMPLE PROCEDURES


 This chapter describes the example workspaces which come with
 LadyBug.  Each section name below is the name of a workspace.
 Issue the command:

    READ "name



 C.1. BCAKE

    to bcake :age

 Draws a birthday cake in color and plays Happy Birthday.
 Submitted by Daniel D. Wheeler, Cincinnati, OH.  Try:

    bcake 5



 C.2. C

    to c :size :level

 Draws a "C". curve.  Adapted from a procedure in TURTLE GRAPHICS.
 Try:

    C 5 6



 C.3. DYNA

    to startup
    to dt :age

 Displays the "Dyna Turtle".  The dyna turtle is really the
 LadyBug acting like a space ship under the influence of Newton's
 Laws.  It starts off motionless at the home position.  The "r"
 and "l" keys turn the ship 30 degrees right and left.  The "k"
 key "kicks" the ship in the direction it is pointing.

 Adapted from LOGO FOR THE APPLE II.











                                                           Page 66






                                     A Guide To Example Procedures


 C.4. DRAGON

    to dragon :size :order

 Draws a dragon curve.  Adapted from TURTLE GRAPHICS.  Try:

    dragon 5 11



 C.5. DUOPOLY

    duopoly :side1 :angle1 :side2 :angle2

 Adapted from TURTLE GRAPHICS.  Try:

    duopoly 12 10 12 -15
    duopoly 18 19 18 -20
    duopoly 45 90 45 320
    duopoly 12 10  4 -15



 C.6. HILBERT

    hilbert :size :level

 Adapted from TURTLE GRAPHICS, page 98.  Draws a Hilbert curve.
 Try:

    hilbert 10 3

 or

    hilbert 5 5



 C.7. INSPI

    to inspi :side :angle :inc

 Adapted from various LOGO books.  Draws an inward spiral with an
 increasing inward turning angle; it thus eventually turns out.
 Slight differences in the angle make totally different pictures.
 For example, try:

    inspi 10 10 15
    inspi 10 10 16
    inspi 10 10 10
    inspi 10 10  7





                                                           Page 67






                                     A Guide To Example Procedures


 C.8. LUDWIG

    to ludwig

 Plays a tune by Beethoven.  Adapted from a BASIC program whose
 author is unknown.



 C.9. MISC

    to corner.tri :size
    to cornerpoly  :size :angle :totalturn
    to nested.triangle :size
    to rays :angle :incangle :dist :incdist
    to tree :l
    to outward.tri :size
    to spiralsq

 CORNER.TRI draws a triangle with smaller triangles on the
 corners.

 CORNERPOLY does a similar thing for general polygons.

 NESTED.TRIANGLE draws triangles inside triangles inside
 triangles.

 Rays draws rays out from the current position.  The rays increase
 in length and angle with time.

 TREE draws a simple tree.

 OUTWARD.TRI is similar to CORNER.TRI.

 SPIRALSQ draws a square with the given size.  Rotates the turtle
 45 degrees and draws another square with a side the length of the
 diagonal of the first square.  Repeats the process with ever
 increasing squares.  Adapted from LOGO FOR THE APPLE II.

 Most of these are adapted from TURTLE GRAPHICS.



 C.10. POLY

    to poly :side :angle

 The basic LOGO procedure.  It draws polygons.  Try:

    poly 100 90
    poly 100 120
    poly 100 144
    poly 100 162



                                                           Page 68






                                     A Guide To Example Procedures


 C.11. POLYSPI

    to polyspi :side :angle :inc

 Very similar to POLY but the side is incremented after each time
 it is drawn.  Try:

    polyspi 1 45 1
    polyspi 5 119 3
    polyspi 5 120 3
    polyspi 5 144 3



 C.12. RAIL

    to rail

 Rail plays a familiar old song but with a complexity that seems
 impossible considering the instrument.  It is adapted from
 RAIL.BAS which was on a disk someone gave the author of LadyBug;
 there was no name on the RAIL program.  Other procedures in the
 workspace are rail1 through rail15 and are called by rail.  Try:

    rail



 C.13. SLINKY

    to shrinkcircle :size
    to rslinky :size
    to spinslink :size
    to growcircle :size

 A set of circle drawing demonstrations adapted from LOGO FOR THE
 APPLE II.  Try:

    shrinkcircle 100
    rslinky 50
    spinslinky 50
    growcircle 10














                                                           Page 69






                                     A Guide To Example Procedures


 C.14. SNOWFLAK

    to snowflake :size :level

 Draws a snowflake. Try:

    snowflake 100 2
    snowflake 100 3



 C.15. SPIRO

    to spiro :size :angle :max

 Adapted from TURTLE GRAPHICS.  Try:

    spiro 5 45 10
    spiro 10 120 7
    spiro 10 90 9



 C.16. SOUNDS

    to ship1
    to ship2
    to ship3
    to clicks
    to clock :tics
    to bird1
    to bird2
    to bird3
    to bird4
    to birds

 A number of different sounds.  Ships are space ships, not ocean
 ships.  The clock ticks the number of times given.  "Birds" makes
 various bird calls.  Try:

    birds
    clock 20
    ship1













                                                           Page 70






                                     A Guide To Example Procedures


 C.17. SPINSQ

    to spinsquares :size

 Draws a square and turns 20 degrees to the right.  Repeats the
 process.  Try:

    spinsquares 50



 C.18. TREES

    to vee
    to branch
    to bush
    to greentree
    to treemove
    to trees

 Adapted from LOGO FOR THE APPLE II.  Try:

    trees

































                                                           Page 71









 APPENDIX D. FORMAT AND CONTENTS OF SAVED WORKSPACES


 Workspaces are saved on disk with the SAVE command and are
 reloaded with the LOAD or READ commands.  The saved workspace
 reflects the definitions of procedures and values of variables
 that existed when the SAVE command was executed.

 The status of currently executing commands or procedures is not
 saved.

 The workspace is saved on disk such that the file contains
 commands which can be executed to rebuild the workspace contents.

 For example, you issue the commands:

    clearws

    to poly :d :a
    ; the standard, simple, POLY procedure
    fd :d
    rt :a
    end

    make "abc "'Some value'
    make "n 4 * 5

    save "dave

 The file DAVE.BUG looks like this:

    to "poly  :d :a
    ; the standard, simple, POLY procedure
    fd :d
    rt :a
    end

    make "abc "'Some value'
    make "n 20

















                                                           Page 72









 APPENDIX E. REDEFINING THE NAMES OF PRIMITIVES



 E.1. .PRIMSYN [LIST]

           .ix.Redefining command names

           The command .PRIMSYM adds synonyms for primitive
           commands.  These synonyms can add words from other
           languages or can redefine what primitive commands do.
           The command has the form:

              .primsyn list

           or

              .primsyn "clear

           The list contains pairs of words.  The first word in a
           pair is the new name for a primitive.  The second is
           the name of the primitive.  The names are truncated to
           8 characters if necessary.  The primitive names are not
           checked for validity; it is possible to add a synonym
           for a primitive that does not exist.

           Each time .primsyn is issued the synonyms are added to
           any existing synonyms.  The command ".primsyn clear"
           clears all synonyms.

           Example:

               .primsyn  [ff forward  bb backward  hd heading]

           This defines 'ff' as a new name for 'forward', 'bb' as
           a new name for 'backward', etc.

           The synonyms are used for both commands and words which
           return values.  LadyBug always looks to see if there is
           a synonym before it looks a name up in its table of
           primitives.

           It is possible to effectively rename primitives with
           .primsyn.  For example:

           Example:

               .primsyn  [fd bk  bk fd]

           This causes all 'fd' commands to become 'bk' and all
           'bk' commands to become 'fd'.





                                                           Page 73









 APPENDIX F. HACKERS ONLY


 This appendix contains commands which may be of interest to
 advanced LadyBug users.  (Advanced users who care about esoteric
 commands are often called "hackers".)



 F.1. .DEBUG

           Turn on debug mode.  In debug mode, each command is
           printed as it is encountered; LadyBug does not pause.
           On occasion, other output also occurs.



 F.2. .STACK

           Display the execution stack showing what procedures,
           repeats, and pauses are active.



 F.3. .SYMTAB

           Display the symbol table.  The name, value, and type of
           every symbol is shown.



 F.4. NAMES THAT RETURN VALUES.

 .LOWWATER

     Returns the position in the symbol table of the last symbol
     belonging to the next procedure up the nest.  Symbols at
     .lowwater + 1 were defined by the current procedure.

 .NVSYM

     The number of symbols in the symbol table.  Some of the
     entries may be empty; if so, their .vval will be "NoToken".

 .VSYM n

     The name of the n'th variable in the symbol table.
     Procedures have the name proc:procname; POLY is named
     "proc:poly".

 .VVAL n

     The value of the n'th variable in the symbol table.



                                                           Page 74






                                                      Hackers Only


 .VTYPE n

     The type of the n'th variable in the symbol table.  The types
     can be "NoToken", "String", "Word", "List", or "Number".
     Each is currently padded with blanks to a length of 8
     characters.

 WARNING: These commands and words are documented for use in
 debugging procedures, not for building applications.  Their
 definitions may change in future releases of LadyBug.














































                                                           Page 75









 APPENDIX G. ERROR MESSAGES


 (PROCEDURE) DIDN'T OUTPUT ANYTHING.
      The procedure was invoked in an expression but the procedure
      did not terminate with an OUTPUT command.

 (COMMAND) DOESN'T LIKE (NUMBER/WORD/LIST) AS INPUT.

 (COMMAND) DOESN'T LIKE TO WORK AFTER YOU SAID DRAW.
      The command works only in text mode; issue the NODRAW
      command and try again.

 (COMMAND) DOESN'T LIKE TO WORK AFTER YOU SAID NODRAW.
      The command works only in graphics mode; issue the RAW
      command and try again.

 (COMMAND) DOESN'T LIKE (WORD/LIST/STRING) AS INPUT.
      The input does not match what the command expects.

 (COMMAND) HAS TOO MANY INPUTS

 (COMMAND) NEEDS MORE INPUTS.

 BACKGROUND DOESN'T LIKE COLOR NUMBER OF (NUMBER)

 CANNOT RAISE NUMBER TO NON-INTEGRAL VALUE

 CANNOT RUN A PROCEDURE WHILE STARTING UP A PROCEDURE.
      A procedure cannot be invoked in an expression which is an
      input to another procedure.

 CURSOR POSITION IS OFF OF SCREEN:  (NUMBER)  (NUMBER)

 DEFINE DOESN'T LIKE (WORD/STRING) AS INPUT.
      DEFINE must have a word as its first input and a list as its
      second input.

 DON'T KNOW HOW TO DO ARITHMETIC ON (WORD)

 DON'T KNOW WHAT TO DO WITH OUTPUT VALUE: (VALUE)
      A procedure ended with an OUTPUT command but the procedure
      was not invoked as a part of an expression.

 EDIT DOESN'T LIKE SO MUCH TO EDIT.
      The number of lines given exceeded the limit of the editor
      or the size of the data exceeded the space available.









                                                           Page 76






                                                    Error Messages


 ERROR CONVERTING (WORD) TO A NUMBER
      The word was in an expression, or in a place where a number
      was expected, but was not a valid number.

 FATAL ERROR (NUMBER) AT (LINE)
      Whoops!  This should never happen but it might.  Please let
      the author know.

 FILE NOT FOUND
      A disk file was not found.

 I DON'T KNOW HOW TO (COMMAND)
      LadyBug could not find the command in its internal table of
      commands and could not find a procedure with the name.

 I DON'T KNOW HOW TO PLAY THIS: (TUNE)
      Something is wrong with the music specification.

 INTERNAL ERROR (NUMBER)
      Whoops!  This should ever happen but it might.  Please let
      the author know.

 INVALID SYMBOL:  (NAME)

 LADYBUG DOESN'T LIKE TO SCRUNCH THIS MUCH:  (NUMBER)
      SETSCRUNCH can accept numbers from .1 to 10 only.

 MAXIMUM NUMBER OF LINES IN USE.
      In the editor, the maximum number of lines is in use.

 MAXIMUM NUMBER OF SYMBOLS REACHED WITH (SYMBOL)
      The symbol table is full.  This might happen if you have a
      very large number of procedures and/or variables.  It might
      also happen if you have paused many times without going back
      to the top level command prompt.

 MISSING VALUE AFTER (WORD)

 PAINT DOESN'T LIKE PAINT COLOR NUMBER OF  (NUMBER)

 PAINT DOESN'T LIKE BOUNDARY COLOR NUMBER OF  (NUMBER)

 PALETTE DOESN'T LIKE PALETTE NUMBER OF  (NUMBER)

 PENCOLOR DOESN'T LIKE COLOR NUMBER OF  (NUMBER)

 PROCEDURE NESTING IS TOO DEEP.
      Too many procedures, repeats, pauses, or uncompleted
      expressions.







                                                           Page 77






                                                    Error Messages


 PROCEDURE (NAME) WAS NOT FOUND.

 RAN OUT OF ROOM IN EXPRESSION.
      Too many procedures, repeats, pauses, or uncompleted
      expressions.

 RUN DOESN'T LIKE (WORD) AS INPUT.  IT EXPECTS A LIST.

 TO OR PROCEDURE NAME MISSING.
      In editor, while trying to save the procedures it was
      discovered that either the keyword TO was missing of the
      name of a procedure was missing.

 TOO MANY ACTIVE FILE REFERENCES; (WORD) IGNORED.
      Commands executed as a result of a READ command have issued
      other READ command to a depth of four.

 TOO MANY REPEAT STATEMENTS ACTIVE.
      Too many procedures, repeats, pauses, or uncompleted
      expressions.

 VARIABLE (NAME) WAS NOT FOUND.

 WARNING: ALMOST OUT OF SPACE.
      The editor is almost out of working space.  It will not let
      you add more characters.






























                                                           Page 78









 APPENDIX H. LIMITS AND CAPACITIES


 Maximum total procedures and variables in workspace
    200

 Maximum total procedure, repeat, pause, read/load, expression,
 and parenthesis nesting depth
    40 total, but see below

 Maximum number of editor lines
    500

 Maximum procedure size, in characters
    32760

 Procedures can appear to nest much deeper than the limit of 40
 due to the recognition of "tail recursion".  When the last thing
 a procedure does is call itself, LadyBug recognizes that it need
 not keep information about the old procedure call since it is
 essentially done.  Therefore such a call does not increase the
 nesting depth.


































                                                           Page 79









 INDEX


 +, 48
 <=, 49
 >, 49
 =, 49
 ^, 48
 \, 49
 >=, 49
 <>, 49
 <, 49
 *, 48
 -, 48



 --- A ---

 ABS keyword, 44
 AND procedure, 52
 Angles, 10
 ARCTAN keyword, 44
 Arithmetic operator
   *, 48
   +, 48
   -, 48
   /, 48
   \, 49
   ^, 48
 ASC keyword, 44
 Aspect ratio, 20, 45
 Author, i
 AUTOEXEC.BAT file, 5
 Automatic startup, 5



 --- B ---

 BACK command, 14
 Background colors, 14, 44
 BACKGROUND command, 14
 BACKGROUND keyword, 44
 Backup, 5
 BEEP command, 23










                                                           Page 80






                                                             Index


 --- C ---

 CATALOG command, 37
 Changes in this version, 3
 CHAR keyword, 44
 CLEARINPUT command, 25
 CLEARSCREEN command, 15
 CLEARTEXT command, 27
 CLEARWS command, 37
 CLIP, 14
 CLIP command, 15
 CO Command, 42
 Color
   background, 14
   numbers, 14
   painting, 18
   palette, 18
   pen colors, 18, 45
 Command name synonyms, 73
 Command prompt, 41
 Comment Command, 43
 CONTINUE Command, 42
 Copying, ii
 COS keyword, 44
 Cursor
   positioning, 27
 CURSOR command, 27



 --- D ---

 DEFINE command, 37
 Defining procedures, 29
 Diskette
   setting up for execution, 7
 Distribution, secondary, ii
 DOS, 2
 DOS GRAPHICS command, 57
 DRAW, 14
 DRAW command, 6, 15



 --- E ---

 ED command, 54
 EDIT command, 29, 38, 54
 Editing active procedures, 42
 Editing files, 29, 54, 59
 Editing screen, 11
 Editor key
   Alt-d: delete area, 59
   Alt-j: join lines, 59


                                                           Page 81






                                                             Index


   Alt-l: mark lines, 59
   Alt-s: split lines, 59
   Alt-u: unmark lines, 60
   Alt-z: copy lines, 60
   Backspace, 55, 60
   Character keys, 55, 60
   Ctrl-End: move to end of file, 60
   Ctrl-Home: move to start of file, 60
   Ctrl-Left: left 40 columns, 60
   Ctrl-Pg Dn: to bottom edge, 60
   Ctrl-Right: right 40 columns, 60
   Cursor keys, 55, 60
   Del, 55, 60
   End, 55
   End: to end of line, 60
   Enter key, 55, 60
   F5: clear line, 55, 61
   F6: clear to EOL, 55, 61
   F7: quit editing, 55, 61
   F9: End editing, 55
   F9: stop editing, 61
   Home, 55, 61
   Ins, 56, 61
   Pg Dn, 56, 61
   Pg Up, 56, 61
   Shift-F4: undo, 61
   Shift-F8: delete line, 56, 61
   Tab, 56, 61
 EDLIN editor, 57
 END command, 29, 54
 ERASE command, 38
 ERASEFILE command, 39
 ERNAME command, 39
 ERROR command, 30
 Error messages, 76
 EXP keyword, 45
 Expressions, 13, 48



 --- F ---

 File
   PROFILE.BUG, 20, 58
 Floating point numbers, 44
 "Foreign" languages, 73
 FOREVER command, 30
 FOREVER procedure, 52
 FORWARD command, 16
 FRED editor, 57
 Function key
   F10: hide LadyBug, 6
   F1: stop drawing, 5
   F3: help, 5


                                                           Page 82






                                                             Index


   F5: pause, 5
   F5: Pausing execution, 41
   F9: trace mode, 6



 --- G ---

 GOODBYE command, 30
 Graphics commands, 14
 Graphics mode, 10, 14, 15, 17, 25
 Graphics screens, 10



 --- H ---

 Heading, 10
 HEADING keyword, 45
 HIDDEN? keyword, 48
 HIDEBUG command, 16
 HIDETURTLE command, 16
 HOME command, 16



 --- I ---

 IF command, 30, 31, 32
 IFFALSE command, 32
 IFTRUE command, 32
 Initialization, 58
 Input and output, 25
 Inputs to procedures, 41
 INTEGER keyword, 45
 Integer numbers, 44



 --- J ---

 Joystick, 47



 --- K ---

 KEYP keyword, 47








                                                           Page 83






                                                             Index


 --- L ---

 LEFT command, 16
 Limits, 42, 79
 Lists, 12, 45
 LOAD command, 39
 LOCAL command, 33
 LOG keyword, 45



 --- M ---

 MAKE command, 34
 MAX procedure, 52
 MIN procedure, 52
 Monochrome display, 2, 11, 54, 59



 --- N ---

 Nested group of procedures, 41
 Nest of procedures, 41
 NOCLIP, 14
 NOCLIP command, 17
 NODRAW, 14
 NODRAW command, 17
 NOT keyword, 50
 NOTRACE Command, 42
 NOWINDOW, 14
 NOWINDOW command, 17
 NOWRAP, 14
 NOWRAP command, 17
 NUMBER? keyword, 45
 Numbers, 12
   floating point, 44
   integers, 44



 --- O ---

 OR procedure, 53
 OUTPUT command, 34











                                                           Page 84






                                                             Index


 --- P ---

 PADDLEBUTTON keyword, 47
 PADDLE keyword, 47
 PAINT command, 18
 Painting, 18
 PALETTE command, 18
 PALETTE keyword, 45
 PAUSE Command, 42
 Pausing, 53
 Pausing procedures, 41
 PC/DOS, 2
 PC keyword, 45
 PENCOLOR command, 18
 PENCOLOR keyword, 45
 PENDOWN command, 19
 PENDOWN? keyword, 47
 PENUP command, 19
 PENUP? keyword, 47
 Performance Hints, 58
 Performance hint, 6, 22
 PLAY command, 23, 62
   examples, 65
 POLY procedure, 6
 POLYSPI procedure, 6
 .PRIMSYN command, 73
 PRINT1 command, 25
 PRINT command, 25
 Printing data, 25
 Printing the screen, 57
 PRINTOUT command, 39
 Procedures, 9, 41
   as commands, 41
   creating, 41
   defining, 29, 37, 40, 54
   inputs to, 41
   maximum number of, 79
   maximum size, 79
   pausing, 41
   returning from, 36
   returning values from, 34
   running, 41
   tail recursion, 79
 Procedure set, 30
 PROFILE.BUG file, 20, 58











                                                           Page 85






                                                             Index


 --- R ---

 RANDOMIZE command, 35
 RANDOM keyword, 45
 RC keyword, 47
 RC? keyword, 47
 READCHARACTER keyword, 47
 READCHAR keyword, 47
 READ command, 40, 57
 References, 1
 Relational expressions, 49, 52
 Relational operator
   <, 49
   <=, 49
   <>, 49
   =, 49
   >, 49
   >=, 49
 REPEAT command, 35
 REQUEST keyword, 47
 Requirements, 2
 RIGHT command, 19
 RQ keyword, 47
 RUN command, 35
 RUN keyword, 45
 Running LadyBug, 5



 --- S ---

 SAVE command, 40
 Screens, 10
   printing, 57
   width, 28
 SCRUNCH keyword, 45
 SE keyword, 45
 SENTENCE keyword, 45
 SETBG command, 20
 SETHEADING command, 19
 SETPAL command, 20
 SETPC command, 20
 SETSCRUNCH, 14
 SETSCRUNCH command, 20
 .SETSCRUNCH command, 20
 Setup for execution, 7
 SETWIDTH command, 28
 SETX command, 20
 SETXY command, 21
 SETY command, 21
 SHOWBUG command, 21
 SHOWING? keyword, 48
 SHOWTURTLE command, 21
 SIGN keyword, 46


                                                           Page 86






                                                             Index


 SIN keyword, 46
 Sounds
   playing tunes, 23, 62
   single notes, 24
 Source code, iii
 SQRT keyword, 46
 STICKBUTTON keyword, 47
 STICK keyword, 47
 STOP command, 36
 Strings, 13



 --- T ---

 TAN keyword, 46
 TEST command, 36
 TEXTCOLUMNS command, 28
 Text Mode, 27
 Text mode, 11, 14, 15, 17, 25, 28
 Text screen, 11
 THING keyword, 46
 TO command, 40
 TONE command, 24
 Tools workspaces, 52
 TOPLEVEL command, 36
 TOPLEVEL Command, 43
 TRACE Command, 43
 TYPE command, 26



 --- U ---

 User Supported Software, i, ii



 --- V ---

 Variables, 9
   assigning, 34
   creating, 34
   maximum number of, 79
   scope, 33, 34
   scope example, 33










                                                           Page 87






                                                             Index


 --- W ---

 WAIT command, 36
 WAIT procedure, 53
 Warrantee, disclaimer of, i
 WHILE command, 36
 WHILE procedure, 53
 WINDOW, 14
 WINDOW command, 22
 WORD keyword, 46
 Words, 12
 Workspace, 9
   managing, 37
 WRAP, 14
 WRAP command, 22



 --- X ---

 XCOR keyword, 46
 XOR procedure, 53



 --- Y ---

 YCOR keyword, 46
 Young People's LOGO Association, 1
 YPLA, 1


























                                                           Page 88