Shareware Grab Bag

home *** CD-ROM | disk | FTP | other *** search

/ Shareware Grab Bag / Shareware Grab Bag.iso / 008 / ladybug.arc / LADYBUG.DOC next >

Wrap

Text File | 1985-09-05 | 148.3 KB | 6,074 lines

LADYBUG GRAPHICS REFERENCE MANUAL VERSION 1.0 14 March 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 guarantees that any problem will be fixed. Please dont 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. Preface Page ii COPYING LADYBUG Educational institutions, clubs, and other nonprofit organizations 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 instutitions, clubs, and other nonprofit organizations 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.(1) ____________________ (1) User-supported does NOT mean that the user must support herself. It means that the user herself supports the idea of freely distributed software. Preface Page iii SOURCE LadyBug is distributed as compiled Basic; 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; it 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. 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. Why not LadyBug?................................... 3 1.5. LadyBug Procedure Library.......................... 4 1.6. 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. When 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).................. 15 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............................................ 16 6.12. NODRAW (Abbreviated ND)......................... 17 6.13. NOWRAP............................................ 17 6.14. NOWINDOW.......................................... 17 6.15. PAINT paintcolor bordercolor...................... 17 6.16. PALETTE palettenumber............................. 18 6.17. PENCOLOR color (Abbreviated PC)................. 18 6.18. PENDOWN (Abbreviated PD)........................ 18 Table of Contents Page v 6.19. PENUP (Abbreviated PU).......................... 19 6.20. RIGHT angle (Abbreviated RT).................... 19 6.21. SETHEADING angle (Abbreviated SETH)............. 19 6.22. SETBG color....................................... 19 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. CLEARTEXT (Abbreviated CT)....................... 25 8.2. CLEARINPUT......................................... 25 8.3. CURSOR column row.................................. 25 8.4. PRINT word (Abbreviated PR)...................... 25 8.5. PRINT1 word (Abbreviated PR1).................... 26 8.6. TYPE word.......................................... 26 8.7. SETWIDTH columns................................... 26 8.8. TEXTCOLUMNS columns (Abbreviated TCOLS).......... 26 9. CONTROL COMMANDS....................................... 27 9.1. EDIT procname ... (Abbreviated ED)............... 27 9.2. EDIT ALL........................................... 27 9.3. END................................................ 27 9.4. ERROR message...................................... 27 9.5. FOREVER list....................................... 28 9.6. GOODBYE (Abbreviated BYE)........................ 28 9.7. IF condition THEN action........................... 28 9.8. IF condition [action].............................. 28 9.9. IF condition THEN action1 ELSE action2............. 29 9.10. IF condition [action1] [action2].................. 29 9.11. IFFALSE list...................................... 30 9.12. IFTRUE list....................................... 30 9.13. LOCAL variablename................................ 30 9.14. MAKE "variablename value.......................... 31 9.15. OUTPUT value (Abbreviated OP)................... 32 9.16. RANDOMIZE number.................................. 32 9.17. REPEAT number list................................ 32 9.18. RUN list.......................................... 33 9.19. STOP.............................................. 33 9.20. TEST condition.................................... 33 9.21. TOPLEVEL.......................................... 33 9.22. WAIT time......................................... 33 9.23. WHILE condition list.............................. 34 Table of Contents Page vi 10. MANAGING THE WORKSPACE................................ 35 10.1. CATALOG (Abbreviated CAT)....................... 35 10.2. CLEARWS........................................... 35 10.3. DEFINE "name list................................. 35 10.4. EDIT procname .................................... 36 10.5. EDIT ALL.......................................... 36 10.6. ERASE procedurename............................... 36 10.7. ERASE ALL......................................... 36 10.8. ERASEFILE filename................................ 37 10.9. ERNAME variablename............................... 37 10.10. ERNAME ALL....................................... 37 10.11. LOAD filename.................................... 37 10.12. PRINTOUT name (Abbreviated PO)................. 37 10.13. READ filename.................................... 37 10.14. SAVE filename.................................... 38 10.15. TO procname inputs............................... 38 11. RUNNING AND DEBUGGING PROCEDURES...................... 39 11.1. Running Procedures................................ 39 11.2. Pausing Procedures................................ 39 11.3. Editing Active Procedures......................... 40 11.4. CONTINUE (Abbreviated CO)...................... 40 11.5. NOTRACE........................................... 40 11.6. PAUSE............................................. 40 11.7. TOPLEVEL.......................................... 40 11.8. TRACE............................................. 41 11.9. ; (comment)...................................... 41 12. NUMBERS AND COMPUTATIONS.............................. 42 12.1. Values............................................ 42 12.1.1. Numeric Values................................ 42 12.1.2. Mathematical Values........................... 43 12.2. Graphics Words.................................... 44 12.3. Other Words....................................... 45 12.4. Expressions Resulting in Numbers.................. 46 12.5. Expressions Resulting in True or False............ 47 12.6. Procedures........................................ 48 13. WORKSPACES WITH TOOLS................................. 49 13.1. AND t/f t/f..................................... 49 13.2. FOREVER list...................................... 49 13.3. MAX value1 value2................................. 49 13.4. MIN value1 value2................................. 49 13.5. OR t/f t/f...................................... 50 13.6. WAIT time......................................... 50 13.7. WHILE [condition] [commands]...................... 50 13.8. XOR t/f t/f..................................... 50 14. INTRODUCTION TO THE LADYBUG EDITOR.................... 51 14.1. About the Editor.................................. 51 14.2. Invoking the Editor............................... 51 14.3. The LadyBug Editor Keys........................... 52 Table of Contents Page vii 15. HINTS ON USING LADYBUG................................ 54 15.1. Printing the Screen On an IBM or Epson Printer.... 54 15.2. Printing the Screen On Other Printers............. 54 15.3. Tailoring LadyBug: The Profile.................... 54 15.4. The READ Command.................................. 54 15.5. Performance Hints................................. 55 APPENDIX A. ABOUT THE LADYBUG EDITOR...................... 57 A.1. The LadyBug Editor Keys............................ 57 APPENDIX B. THE PLAY COMMAND.............................. 60 B.1. Music Commands..................................... 60 B.2. Examples of Play Statements........................ 63 APPENDIX C. A GUIDE TO EXAMPLE PROCEDURES................. 64 C.1. BCAKE.............................................. 64 C.2. C.................................................. 64 C.3. DYNA............................................... 64 C.4. DRAGON............................................. 65 C.5. DUOPOLY............................................ 65 C.6. HILBERT............................................ 65 C.7. INSPI.............................................. 65 C.8. LUDWIG............................................. 66 C.9. MISC............................................... 66 C.10. POLY.............................................. 66 C.11. POLYSPI........................................... 67 C.12. RAIL.............................................. 67 C.13. SLINKY............................................ 67 C.14. SNOWFLAK.......................................... 68 C.15. SPIRO............................................. 68 C.16. SOUNDS............................................ 68 C.17. SPINSQ............................................ 69 C.18. TREES............................................. 69 APPENDIX D. FORMAT AND CONTENTS OF SAVED WORKSPACES....... 70 APPENDIX E. ERROR MESSAGES................................ 71 APPENDIX F. HACKERS ONLY.................................. 74 F.1. .DEBUG............................................. 74 F.2. .STACK............................................. 74 F.3. .SYMTAB............................................ 74 F.4. Names that return values........................... 74 APPENDIX G. LIMITS AND CAPACITIES......................... 76 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(2) implementation of LOGO done by Terrapin, Inc. This version 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(3) computers. Words from other LOGO implementations are included for compatibility. 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 more advanced users. 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 People's 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. ____________________ (2) Apple II is a Trademark of Apple, Inc. (3) TRS-80 is a Trademark of Tandy. About LadyBug and LOGO Page 2 1.1. LADYBUG FEATURES LadyBug is a version of LOGO patterned after the Apple II implementation developed by Terrapin, Inc. and with features from other LOGO systems. In general it has most of the graphics commands, the mathematical computations, and the control commands, of Apple LOGO. In addition it has: - Commands and words from various other LOGO implementations. Commands with the same names as IBM LOGO commands are mainly compatible with IBM LOGO. - A library of procedures adapted from a variety of sources. - Painting of areas. - Clipping of drawings (as well as wraparound). - A fast full screen editor. - Support for using both displays if both are present. - Sounds -- PLAY statement like Basic. The major features missing are: - List manipulation. - Variable numbers of parameters to primitives. - Saving screen images. 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, PCjr, 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. 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. About LadyBug and LOGO Page 3 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. WHY NOT LADYBUG? LadyBug was written as an introduction to LOGO and Turtle Graphics.(4) 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: 1. LadyBug is slower. 2. LadyBug doesn't do as much. 3. 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. 4. LadyBug will not grow and progress significantly with time. 5. 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. ____________________ (4) In particular, it was done for the author's children; thoughts of distribution only came later. About LadyBug and LOGO Page 4 1.5. LADYBUG PROCEDURE LIBRARY There is not much now except those 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. Contirbute them either to the author or to the Young Peoples LOGO Association. 1.6. THANKS TO --- Thanks to the inventors of LOGO for inventing it. Thanks to my children for playing with LadyBug. Thanks to all of those who ran version 0.9 and sent problem reports and requests for changes. The bugs have been fixed and as many features have been added as possible. 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. 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 a friend 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.(5) 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 ____________________ (5) 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. Running LadyBug Page 6 (or CO). F1 will stop procedures invoked from a pause level 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(6) and 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: ____________________ (6) DRAW tells LadyBug you want to do graphics; you only have to do it once at the start. Running LadyBug Page 7 draw polyspi 5 175 5 POLY is a three statement procedure. POLYSPI is too. The wide 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 many things, such as documentation, 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 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. Other .BUG files can be copied as needed. 4. If you want the diskette to automatically startup 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 Running LadyBug Page 8 2.6. WHEN 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 ane 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. 3. THE WORKSPACE LadyBug provides a work area in which you keep variables and procedures. This work area is called a "work space". The work space initially contains only the procedure POLY. Many LadyBug commands add to, modify things in, or remove things from the workspace. COMMAND ACTION CLEARWS Deletes everything in the workspace EDIT Add or changes 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 say BYE and leave LadyBug without saving the workspace or you can say SAVE and save it first. SAVE allows you to name the workspace however you wish. 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 "polyspi", that you make up. Later on we will talk about how to create procedures. Variables Variables are named values. They 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. 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.(7) 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.(8) 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. ____________________ (7) This area is two lines of up to 80 characters total. (8) 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. LadyBug can hide these differences. The LadyBug Screens Page 11 150 +----+----+----+----+----+----+----+----+----+----+ | | | | 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. 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. Things Which Make Up Commands Page 13 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. Everyplace 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 + 4 * sin :angle 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. Examples: back 50 back :a + 1 bk 2 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. Examples: background 8 bg 0 Graphics Commands Page 15 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.) 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. Examples: forward 50 fd 10 Graphics Commands Page 16 6.7. HIDEBUG (ABBREVIATED HB) Takes no inputs. Makes the LadyBug disappear from the screen. May also be written as HIDETURTLE (abbreviated as HT). 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 from -360 to 360. Rotates the LadyBug that many degrees counterclockwise. Example: 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. Graphics Commands Page 17 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 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. 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. Graphics Commands Page 18 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 6.18. PENDOWN (ABBREVIATED PD) Takes no inputs. When the pen is down, the LadyBug draws when she moves. Graphics Commands Page 19 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 from -360 to 360. Rotates the LadyBug that many degrees clockwise. 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 -360 to +360. 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 6.22. SETBG COLOR Same as BACKGROUND in this chapter. Graphics Commands Page 20 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. Graphics Commands Page 21 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. Graphics Commands Page 22 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. 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 60 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 Sounds Page 24 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 8. INPUT AND OUTPUT This chapter describes statements which read or write data, which control the text screen, or which sense what is happening with a keyboard or joystick. These commands are value in both graphics mode and text mode unless noted otherwise. 8.1. 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. 8.2. CLEARINPUT Takes no inputs. Clears the input buffer of text typed but not yet read. 8.3. 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 1-40 (or 1-80 depending upon the number of text columns) and the row may be 1-25. The cursor command is valid only in text mode. Example: cursor 20 1 8.4. PRINT WORD (ABBREVIATED PR) Takes one input which it prints on the current output device. Moves the cursor to the next line. Input and Output Page 26 8.5. 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. 8.6. 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. 8.7. SETWIDTH COLUMNS Same as TEXTCOLUMNS in this chapter. 8.8. 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. The command is value anytime but it takes effect only when in text mode and when text mode is displayed on the graphics device. On the Monochrome display, text mode always has 80 columns. 9. CONTROL COMMANDS This chapter describes commands which are used to define variables and procedures. 9.1. 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 51 describes this command and how to use the editor. Examples: edit poly ed poly polyspi square 9.2. EDIT ALL Edit all procedures at one time. 9.3. 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. See also the TO command. 9.4. 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 39.) Control Commands Page 28 9.5. FOREVER LIST See chapter "The Workspace Named 'TOOLS'". on page 49. 9.6. GOODBYE (ABBREVIATED BYE) Exit to DOS from LadyBug. 9.7. 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. 9.8. 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 Control Commands Page 29 Also see the TEST command. 9.9. 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. 9.10. 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. Control Commands Page 30 9.11. 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] 9.12. 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] 9.13. 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 Control Commands Page 31 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. 9.14. 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 Control Commands Page 32 are examined. If no variable is found, then MAKE makes a new variable. It is local to the current procedure if one is active. New 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. 9.15. 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] 9.16. 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, calls to RANDOM will return the same sequence of random numbers. Examples: randomize 2127 randomize :seed + 1173 9.17. REPEAT NUMBER LIST Takes two inputs, a number and a list. RUNs the list as many times as the number indicates. Examples: repeat 4 [forward 100 right 90] repeat :n :alist Control Commands Page 33 9.18. 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 9.19. STOP Takes no inputs. Causes the current procedure to stop and return control to the procedure which called it, if any, else or to the command prompt. No value is output. 9.20. 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; it can be tested by the IFTRUE and IFFALSE commands. 9.21. TOPLEVEL Takes no inputs. Stops all active commands, procedures and PAUSEs. Returns to the command prompt. 9.22. WAIT TIME See chapter "Workspaces With Tools". on page 49. Control Commands Page 34 9.23. WHILE CONDITION LIST See chapter "Workspaces With Tools" on page 49. 10. MANAGING THE WORKSPACE This chapter describes statements which are used to control and manage the workspace. 10.1. CATALOG (ABBREVIATED CAT) Takes no inputs. Prints the names of files contained on the current disk. The current screen is cleared and the catalog is displayed as if in text mode. 10.2. CLEARWS Takes no inputs. Clears all variables and procedures from the workspace. 10.3. 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 end Managing the Workspace Page 36 can be defined as: define "circ [[][fd 10][rt 10][circ]] 10.4. 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 51 describes this command and how to use the editor. Examples: edit poly ed poly polyspi square 10.5. EDIT ALL Edit all procedures at one time. 10.6. ERASE PROCEDURENAME Delete the procedure named. Example: erase "poly NOTE: ERASE can be used to delete a procedure from within itself without disturbing the execution of the procedure. 10.7. ERASE ALL Delete all procedures. Managing the Workspace Page 37 10.8. ERASEFILE FILENAME Erase the disk file named. Example: erasefile "b:brough.bug 10.9. ERNAME VARIABLENAME Delete the variable named. Example: ername "bart 10.10. ERNAME ALL Delete all variables. 10.11. LOAD FILENAME Same as READ in this chapter. 10.12. PRINTOUT NAME (ABBREVIATED PO) Print the value of the variable and/or definition of the procedure with the name given. Example: printout "elephant 10.13. READ FILENAME Load the named workspace and add its variables and procedures to the workspace. If no file extension is given, .BUG is used. Managing the Workspace Page 38 Examples: read "polyspi read "b:circ.lgo See the chapter "Hints on Using LadyBug" on page 54 for more information about uses of READ. 10.14. 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. 10.15. 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. All 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 :ang end 11. RUNNING AND DEBUGGING PROCEDURES This chapter describes how to run procedures and describes some commands which help debug them. 11.1. 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 predefined, 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. 11.2. 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 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 Running and Debugging Procedures Page 40 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. 11.3. 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. 11.4. CONTINUE (ABBREVIATED CO) The continue command resumes execution of a paused procedure set. 11.5. NOTRACE Turn off tracing. 11.6. PAUSE Pause the current nest of procedures. 11.7. TOPLEVEL Terminate all active procedures in all active procedure sets, and all active commands. Return to the top level command prompt. Running and Debugging Procedures Page 41 11.8. 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. 11.9. ; (COMMENT) Any line which starts with a semicolon is a comment line. The contents of the line are ignored. 12. NUMBERS AND COMPUTATIONS This section describes numbers and how to compute with them. 12.1. VALUES 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 the 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. 12.1.1. NUMERIC VALUES Several words in Ladybug have values. None of the following take any inputs: BACKGROUND (Abbreviated BG) The background color. HEADING The angle that the LadyBug is currently facing. The value ranges from -359 to 359. PALETTE The palette number. PENCOLOR (Abbreviated PC) The color of the pen. SCRUNCH The value of the aspect ratio asjustment. See the SETSCRUNCH command. XCOR The current x coordinate of the LadyBug. Numbers and Computations Page 43 YCOR The current y coordinate of the LadyBug. 12.1.2. MATHEMATICAL VALUES These Ladybug words take one value (an expression) and return a number. ABS number Returns the absolute value of the number. ARCTAN tangent Returns the angle which has the tangent given. COS angle Returns the cosine of the angle in degrees. EXP power Returns the mathematical quantity 'e' raised to the power given. 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. RANDOM range Returns a random number in the range 0 to 'range'. (See the RANDOMIZE statement for more information.) 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. Numbers and Computations Page 44 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 12.2. GRAPHICS 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 character if the buffer is empty. REQUEST (Abbreviated RQ) Takes no inputs. Waits for an input 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 everyting 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. Numbers and Computations Page 45 SHOWING? and HIDDEN? Neither takes an input. Both return either "true" or "false" depending upon whether the LadyBug is showing or hidden. 12.3. OTHER WORDS NUMBER? word Takes one input. Returns "true" if the word represents a number and "false" if it does not. 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". 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". 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. Examples: make "x sentence [a b] [c d] make "x sentence joe [frank bob] 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 Numbers and Computations Page 46 CHAR expression Takes one input, a number from 0 to 255. Returns the ASCII character which corresponds to that number. 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. 12.4. 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. Numbers and Computations Page 47 ^ (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. \ (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 print the same result. 12.5. EXPRESSIONS RESULTING IN TRUE OR FALSE Expressions which result in "true" or "false" are similar to expressions which result in numbers and may have such expressions in them. Each expression has 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 49. Numbers and Computations Page 48 In addition: 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 12.6. 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, it 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: Example: print 5 + v v 6 If allowed, it would increment the 6 twice. 13. WORKSPACES WITH TOOLS This chapter describes procedures which are in the workspace named TOOLS. An appendix describes other workspaces which contain example procedures. 13.1. 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: and :a < 2 :b > 4 13.2. FOREVER LIST Takes one input, a list. RUNs the list over and over, forever. Example: if and :a > 3 :a < 10 [fd :a] 13.3. MAX VALUE1 VALUE2 Takes, two inputs, both expressions which return some value. Returns the largest of the two. 13.4. MIN VALUE1 VALUE2 Takes, two inputs, both expressions which return some value. Returns the smallest of the two. Workspaces With Tools Page 50 13.5. 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] 13.6. WAIT TIME Takes one input, a time in seconds. LadyBug pauses for this length of time. 13.7. 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] 13.8. 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] 14. 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 57 describes additional features of the editor. 14.1. 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 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. 14.2. 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. Introduction to the LadyBug Editor Page 52 14.3. 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. Introduction to the LadyBug Editor Page 53 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.) 15. HINTS ON USING LADYBUG This chapter contains several helpful hints about how to use LadyBug effectively. 15.1. PRINTING THE SCREEN ON AN IBM OR EPSON PRINTER 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. If the printer is an Epson, it must have the GrafTrax feature builtin or added. 15.2. 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. 15.3. 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. For example, the PROFILE might contain: pencolor 1 background 7 15.4. THE READ COMMAND The READ command described on page 37 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.(9) ____________________ (9) The author of LadyBug has a free editor called FRED which Hints On Using LadyBug Page 55 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. When LadyBug starts up, it READs a file named PROFILE.BUG. This file may be modified to perform any action you wish as a part of the startup process. READ files can be created which contain long sequences of 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. 15.5. 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 30 percent faster than POLYA. to polya :d :a fd :d rt :a poly :d :a end to polyb :d :a fd :d rt :a fd :d rt :a poly :d :a end - Repeat instead of recurse. POLYC is 50 percent faster than POLYA. to polyc :d :a repeat 1000 [fd :d rt :a] poly :d :a end Minor improvements: - Turn on NOCLIP and NOWRAP when there is no danger of needing them. - Put multiple statements on a line. ____________________ will create such files; send a diskette in a self-addressed, post-paid diskette mailer for a free copy. FRED is very similar to the LadyBug editor. However any editor will do, including the EDLIN program which comes with DOS. Hints On Using LadyBug Page 56 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. 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 nears the limit 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. About the LadyBug Editor Page 58 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.) About the LadyBug Editor Page 59 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.) 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 The PLAY Command Page 61 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". The PLAY Command Page 62 ---------------- 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. The PLAY Command Page 63 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'] Now, a clock ticking: Example: to clock :tics play "'L50 MB MS T255' repeat :tics [play "'N1 P1 N2 P1'] 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' 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. A Guide To Example Procedures Page 65 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 hilbert 5 5 C.7. INSPI to inspi :side :angle :inc Adapted from various LOGO books. Draws an inward spiral with an increasing inturning 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 A Guide To Example Procedures Page 66 C.8. LUDWIG to ludwig Plays a tune by Beethoven. Adapted from a BASIC program; author 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. NESTER.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 even 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 A Guide To Example Procedures Page 67 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 tools adapted from LOGO FOR THE APPLE II. Try: shrinkcircle 100 rslinky 50 spinslinky 50 growcircle 10 A Guide To Example Procedures Page 68 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 A Guide To Example Procedures Page 69 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 APPENDIX D. FORMAT AND CONTENTS OF SAVED WORKSPACES Workspaces are saved on disk with the SAVE command and are reloaded with the LOAD command. 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 or to add the workspace contents to another workspace. For example, you issue the commands: clearws to poly :d :a ; the standard, simple, POLY procuedure 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 procuedure fd :d rt :a end make "abc "'Some value make "n 20 APPENDIX E. ERROR MESSAGES (PROCEDURE) DIDN'T OUTPUT ANYTHING. The procedure was invoked in an expression but did not terminate with an OUTPUT command. (COMMAND) DOESN'T LIKE (NUMBER) AS INPUT. (COMMAND) DOES NOT LIKE (WORD) 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. 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 alist 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. 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. Error Messages Page 72 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 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 LINE PALETTE NUMBER OF (NUMBER) PENCOLOR DOESN'T LINE COLOR NUMBER OF (NUMBER) PROCEDURE NESTING IS TOO DEEP. Too many procedures, repeats, pauses, or uncompleted expressions. PROCEDURE (WORD) WAS NOT FOUND. RAN OUT OF ROOM IN EXPRESSION. Too many procedures, repeats, pauses, or uncompleted expressions. Error Messages Page 73 RUN DOESN'T LIKE (WORD) AS INPUT. IT EXPECTS A LIST. TEST DOESN'T LIKE (WORD) AS INPUT. 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. 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 occassion, 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 symtol table. Some of the entries may be empty; if so, their .vval will be "NoToken". .VSYM n The name of the n'th varible 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. Hackers Only Page 75 .VTYPE n The type of the n'th variable in the symtol 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 definition may change in future releases of LadyBug. APPENDIX G. 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 30 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. INDEX =, 48 <=, 48 >, 48 >=, 48 ^, 47 \, 47 *, 47 +, 47 <, 48 <>, 48 -, 47 --- A --- ABS keyword, 44 AND procedure, 50 ARCTAN keyword, 44 Arithmetic operator *, 47 +, 47 -, 47 /, 47 \, 47 ^, 47 Aspect ratio, 21, 43 Author, i AUTOEXEC.BAT file, 5 Automatic startup, 5 --- B --- BACK command, 15 Background colors, 15, 43 BACKGROUND command, 15 BACKGROUND keyword, 43 Backup, 5 BEEP command, 24 Index Page 78 --- C --- CATALOG command, 36 Changes in this version, 3 CLEARINPUT command, 26 CLEARSCREEN command, 16 CLEARTEXT command, 26 CLEARWS command, 36 CLIP, 15 CLIP command, 16 CO Command, 41 Color background, 15 numbers, 15 painting, 18 palette, 19 pen colors, 19, 43 Command prompt, 40 Comment Command, 42 CONTINUE Command, 41 Copying, ii COS keyword, 44 Cursor positioning, 26 CURSOR command, 26 --- D --- DEFINE command, 36 Defining procedures, 28 Diskette setting up for execution, 7 Distribution, secondary, ii DOS, 2 DOS GRAPHICS command, 55 DRAW, 15 DRAW command, 6, 16 --- E --- ED command, 52 EDIT command, 28, 37, 52 Editing active procedures, 41 Editing files, 28, 52, 58 Editing screen, 11 Editor key Alt-d: delete area, 58 Alt-j: join lines, 58 Alt-l: mark lines, 58 Alt-s: split lines, 58 Alt-u: unmark lines, 59 Index Page 79 Alt-z: copy lines, 59 Backspace, 53, 59 Character keys, 53, 59 Ctrl-End: move to end of file, 59 Ctrl-Home: move to start of file, 59 Ctrl-Left: left 40 columns, 59 Ctrl-Pg Dn: to bottom edge, 59 Ctrl-Right: right 40 columns, 59 Cursor keys, 53, 59 Del, 53, 59 End, 53 End: to end of line, 59 Enter key, 53, 59 F5: clear line, 53, 60 F6: clear to EOL, 53, 60 F7: quit editing, 53, 60 F9: End editing, 53 F9: stop editing, 60 Home, 53, 60 Ins, 54, 60 Pg Dn, 54, 60 Pg Up, 54, 60 Shift-F4: undo, 60 Shift-F8: delete line, 54, 60 Tab, 54, 60 EDLIN editor, 55 END command, 28, 52 ERASE command, 37, 37 ERASEFILE command, 38 ERNAME command, 38, 38 ERROR command, 28 EXP keyword, 44 Expressions, 14, 47 --- F --- File PROFILE.BUG, 21, 55, 56 Floating point numbers, 43 FOREVER command, 29 FOREVER procedure, 50 FORWARD command, 16 FRED editor, 55 Function key F10: hide LadyBug, 6 F1: stop drawing, 5 F3: help, 5 F5: pause, 5 F5: Pausing execution, 40 F9: trace mode, 6 Index Page 80 --- G --- GOODBYE command, 29 Graphics commands, 15 Graphics mode, 10, 15, 16, 18, 26 Graphics screens, 10 --- H --- HEADING keyword, 43 HIDDEN? keyword, 45 HIDEBUG command, 17 HIDETURTLE command, 17 HOME command, 17 --- I --- IF command, 29, 29, 30, 30 IFFALSE command, 31 IFTRUE command, 31 Initialization, 55 Input and output, 26 INTEGER keyword, 44 Integer numbers, 43 --- J --- Joystick, 45 --- K --- KEYP keyword, 45 --- L --- LEFT command, 17 Limits, 40, 76 Lists, 13, 46 LOAD command, 38 LOCAL command, 31 LOG keyword, 44 Index Page 81 --- M --- MAKE command, 32 MAX procedure, 50 MIN procedure, 50 Monochrome display, 2, 12, 52, 58 --- N --- Nested group of procedures, 40 Nest of procedures, 40 NOCLIP, 15 NOCLIP command, 17 NODRAW, 15, 15 NODRAW command, 18 NOT keyword, 48 NOTRACE Command, 41 NOWINDOW, 15 NOWINDOW command, 18 NOWRAP, 15 NOWRAP command, 18 NUMBER? keyword, 46 Numbers, 13 floating point, 43 integers, 43 --- O --- OR procedure, 51 OUTPUT command, 33 --- P --- PADDLEBUTTON keyword, 45 PADDLE keyword, 45 PAINT command, 18 Painting, 18 PALETTE command, 19 PALETTE keyword, 43 PAUSE Command, 41 Pausing, 51 Pausing procedures, 40 PC/DOS, 2 PC keyword, 43 PENCOLOR command, 19 PENCOLOR keyword, 43 PENDOWN command, 19 PENDOWN? keyword, 45 PENUP command, 20 Index Page 82 PENUP? keyword, 45 Performance hint, 6, 23 Performance Hints, 56 PLAY command, 24, 61 examples, 64 POLY procedure, 6 POLYSPI procedure, 6 PRINT1 command, 27 PRINT command, 26 Printing data, 26 Printing the screen, 55 PRINTOUT command, 38 Procedures, 9, 40 as commands, 40 creating, 40 defining, 28, 36, 39, 52 maximum number of, 76 maximum size, 76 pausing, 40 returning from, 34 returning values from, 33 running, 40 tail recursion, 76 Procedure set, 28 PROFILE.BUG file, 21, 55, 56 --- R --- RANDOMIZE command, 33 RANDOM keyword, 44 RC? keyword, 45 RC keyword, 45 READCHARACTER keyword, 45 READCHAR keyword, 45 READ command, 38, 55 References, 1 Relational expressions, 48, 50 Relational operator <, 48 <=, 48 <>, 48 =, 48 >, 48 >=, 48 REPEAT command, 33 REQUEST keyword, 45 Requirements, 2 RIGHT command, 20 RQ keyword, 45 RUN command, 34 RUN keyword, 46 Running LadyBug, 5 Index Page 83 --- S --- SAVE command, 39 Screens, 10 printing, 55 width, 27 SCRUNCH keyword, 43 SE keyword, 46 SENTENCE keyword, 46 SETBG command, 20 SETHEADING command, 20 SETPAL command, 21 SETPC command, 21 SETSCRUNCH, 15 SETSCRUNCH command, 21 .SETSCRUNCH command, 21 Setup for execution, 7 SETWIDTH command, 27 SETX command, 21 SETXY command, 22 SETY command, 22 SHOWBUG command, 22 SHOWING? keyword, 45 SHOWTURTLE command, 22 SIGN keyword, 44 SIN keyword, 44 Sounds playing tunes, 24 single notes, 25 Source code, iii SQRT keyword, 44 STICKBUTTON keyword, 45 STICK keyword, 45 STOP command, 34 Strings, 14 --- T --- TAN keyword, 44 TEST command, 34 TEXTCOLUMNS command, 27 Text mode, 11, 15, 16, 18, 26, 27 Text screen, 11 THING keyword, 46 TO command, 39 TONE command, 25 Tools workspacea, 50 TOPLEVEL Command, 41 TOPLEVEL command, 34 TRACE Command, 41 TYPE command, 27 Index Page 84 --- U --- User Supported Software, i, ii --- V --- Variables, 9 assigning, 32 creating, 32 maximum number of, 76 scope, 31, 32 scope example, 32 --- W --- WAIT command, 34 WAIT procedure, 51 Warrantee, disclaimer of, i WHILE command, 35 WHILE procedure, 51 WINDOW, 15 WINDOW command, 23 WORD keyword, 46 Words, 13 Workspace, 9 managing, 36 WRAP, 15 WRAP command, 23 --- X --- XCOR keyword, 43 XOR procedure, 51 --- Y --- YCOR keyword, 44 Young People's LOGO Association, 1 YPLA, 1