Home » Archimedes archive » Archimedes World » AW-1992-10.adf » AWOct92 » !AWOct92/Goodies/Logo/Technical/ASCII
!AWOct92/Goodies/Logo/Technical/ASCII
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » Archimedes archive » Archimedes World » AW-1992-10.adf » AWOct92 |
| Filename: | !AWOct92/Goodies/Logo/Technical/ASCII |
| Read OK: | ✔ |
| File size: | 24D4 bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
The logo interpreter By Duncan F. McPherson
Technical Details
Welcome to logo V1.0
My logo interpreter is now finished, and amongst many new
features, it now offers the ability to save your logo program`s
output as a sprite file or a draw file (so you can have logo
generated lineart in your DTP documents e.t.c.).The interpreter
supports loops, subroutines, command abbreviations and
expressions (though not variables).All the usual logo commands
are there as well, making graphics programming childsplay (even
for big kids!).
Driving a buggy
The robot driver program also comes with a fully working
driver program, in its application directory (under the filename
2Motors).This driver works with an Acorn User port expansion card
(on my A3000) to drive my simple home made buggy (Made from plans
in the Usborne book ROBOTICS).I have designed my !Robot
application so anyone can easily rewrite the basic library file
"Driver" with their own code to drive any buggy under the
sun.This system also allows for pleanty of future expansion.
See the REM lines in the basic file 2Motots for more details
Entering Programs
To create a logo program you need to use a text editor such as
edit or 1st word plus (in non wp mode).Once you have finished
typing in your program check it over thoroughly, and make sure
that every statement in the program is separated by either a a
new-line code (&0D) or a `:` character.Statements that haven`t
been separated properly will generate errors when you try to run
your program in the interpreter.
The logo command line
The command line window inside the logo application can be
used to execute subroutines (by typing their names) or any normal
logo command.Note that you cannot define TO subroutines at the
command line, this can only be done using a textfile program.The
program searches the currently loaded program for any name you
type that it does not recognise as one of it`s own commands, only
throwing back an error if no TO subroutine can be found going by
that name
Any normal logo command can be used at the command line
(forward,back,left e.t.c.), as well as loops and TO subroutine
names.Commands are separated as usual by the `:` character
The HELP function
The help function is supported as a window available by
clicking on `HELP` in the programs menu tree or by typing HELP
followed by the logo command you would like help on.
Program execution
Because the logo interpreter was written in BASIC, execution
is not as fast as it might be.Also the wimp environment slows
down programs, as extensive redrawing of the interpreters display
window is necessary every time the turtle is moved or a line is
drawn.To help speed up the programs execution, close the programs
display and command line windows leaving the program status
window open only, to indicate programs progression.
Loops
The interpreter uses a stack system to keep track of current
loops so you can nest loops at the command line or inside your
programs.
The structure of a loop is as follows :
[<number of times to execute the loop> <== start of loop
FORWARD 100
RIGHT 90 <== statements
e.t.c.
] <== end of loop
Try the following at the command line:
[24:Forward 50:Right 15:]
This short statement draws a circle by repeating the
statements forward 100 and right 15 twenty four times.
The looping system provided is a powerful feature of the
interpreter, and can be used to repeat any logo command or
commands several times.
`To` subroutines
The interpreter has provisions for subroutines via the TO and
EndTo commands.A subroutine takes the format as follows :
TO <name of routine> <== start defining the subroutine <name>
FORWARD 100
RIGHT 90 <== statements
ENDTO <== Tells logo that`s the end of the
subroutine
The subroutine can then be executed at either the command
line or inside the program by typing its name only.
Note subroutines cannot be defined at the command line.
The FINISH command
This command stops the execution of the program currently
running.It is needed to prevent the interpreter carrying on as it
normally would to the end of a program, when a program contains
one or more TO subroutine definitions, as if the interpreter
tries to execute these sequentially an error will be generated.
The Error messages
The interpreter generates the following error messages which
are displayed in its command line window :
Bad logo parameter
No such subroutine
Too many TO subroutines
Not in a TO subroutine
These messages reflect an error in either the users program or
the statement just typed in at the command line window.
Background Execution
Execution of logo programs takes place in the background (via
the wimp`s null reason code), but statements at the command line
take over the machine during their execution.This is not normally
noticeable unless you have entered commands which will take some
time to execute at the command line.To stop a command during its
execution at the command line hit the escape key a few times
Running Programs
Programs can be run by either typing `RUN` at the logo command
line or by clicking on RUN in the program status window.This
window can be displayed by clicking on the `program` option in
the interpreters main menu tree, though this should not normally
be necessary, as the interpreter brings up the status window as
soon as a program is loaded.
Overheads
Every time a logo command which moves the turtle is executed,
the interpreter broadcasts a message over the wimp message system
describing the command just executed.This message will normally
be intercepted by a robot driver program which will in turn move
a turtle around.The format of this message is as follows :
Wimp poll code 17 (user message)
message_block!16=&4C4F474F ("LOGO" in ASCII")
message_block!20=command number
message_block+24=numeric string containing a parameter
to go with the command.
The command numbers are as follows :
1. Forward (the parameter is the distance)
2. Back (the parameter is the distance)
3. Left (the parameter is the angle in degrees)
4. Right (the parameter is the angle in degrees)
5. Penup (no parameter)
6. PenDown (no parameter)
7. PenColour (the parameter is the colour 0-16)
Using this messages the application !Robot will be able to
drive floor turtles via a logo program or commands at the logo
command line.Presently the !Robot program only displays messages
received in its windows, but I have left it easily alterable
(just fill in the blank procedures) so that I can make it drive
various buggy`s and floor turtles at a later data.
Comments inserted into programs
You can insert any comment you like in your ASCII text
program file after a `/` command.This command behaves just like
BASIC`s REM command.
Remember that after your comment still put in a `:` character
or a return code, to separate it from the next statement.The same
goes for the statement before your comment.
The basic logo commands
Forward <distance> Moves your turtle forward the distance
specified by you in the parameter following it.
Back <distance> Moves the turtle back <distance> units
Left <angle> Turns the turtle anti-clockwise through <angle>
degrees
Right <angle> Turns the turtle clockwise through <angle> degrees
PenUp Tells the interpreter not to draw lines
PenDown Tells the interpreter to draw lines when the turtle moves
PenColour <colour> Tells the interpreter to draw the lines in
colour <colour>
Home Moves the turtle back to its home position and angle
SetHome Takes the current position and angle to be the turtles
home position and angle
Clear Clears the logo display window to the default white
ReStart Resets the entire logo display (not the program running)
Angle <degrees> Sets the turtle`s angle to <degrees>
Run Tells the interpreter to begin executing the currently
loaded logo textfile program
Most logo commands have minimum abbreviations, which can make
program entry easier.Many numeric parameters can have
mathematical expressions used in place of just numbers though
variables are not supported currently.Also note that the letter
case of the commands dosen`t matter, the interpreter will
recognise the command either way.
To find out a commands abbreviation use the help window
(available by clicking on help in the interpreters main menu
tree).Once the window is displayed click on the command you want
to know about.
Debugging your program
Debugging a logo program is mainly up to the user, however the
percentage display in the program status window, constantly
updated whilst a program is run, will indicate the percentage
through the programs textfile, the command where the error
occurred was after the bug is reached.
I have found a common sources of errors in programs are either
mistyped commands (generating `No such subroutine`) and missing
separators between statements (generating `Bad Logo parameter`).
00000000 20 20 20 20 20 20 20 20 20 20 20 54 68 65 20 6c | The l| 00000010 6f 67 6f 20 69 6e 74 65 72 70 72 65 74 65 72 20 |ogo interpreter | 00000020 42 79 20 44 75 6e 63 61 6e 20 46 2e 20 4d 63 50 |By Duncan F. McP| 00000030 68 65 72 73 6f 6e 0a 0a 20 20 20 20 20 20 20 20 |herson.. | 00000040 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00000050 54 65 63 68 6e 69 63 61 6c 20 44 65 74 61 69 6c |Technical Detail| 00000060 73 0a 0a 57 65 6c 63 6f 6d 65 20 74 6f 20 6c 6f |s..Welcome to lo| 00000070 67 6f 20 56 31 2e 30 0a 0a 20 20 20 4d 79 20 6c |go V1.0.. My l| 00000080 6f 67 6f 20 69 6e 74 65 72 70 72 65 74 65 72 20 |ogo interpreter | 00000090 69 73 20 6e 6f 77 20 66 69 6e 69 73 68 65 64 2c |is now finished,| 000000a0 20 61 6e 64 20 61 6d 6f 6e 67 73 74 20 6d 61 6e | and amongst man| 000000b0 79 20 6e 65 77 20 0a 66 65 61 74 75 72 65 73 2c |y new .features,| 000000c0 20 69 74 20 6e 6f 77 20 6f 66 66 65 72 73 20 74 | it now offers t| 000000d0 68 65 20 61 62 69 6c 69 74 79 20 74 6f 20 73 61 |he ability to sa| 000000e0 76 65 20 79 6f 75 72 20 6c 6f 67 6f 20 70 72 6f |ve your logo pro| 000000f0 67 72 61 6d 60 73 20 0a 6f 75 74 70 75 74 20 61 |gram`s .output a| 00000100 73 20 61 20 73 70 72 69 74 65 20 66 69 6c 65 20 |s a sprite file | 00000110 6f 72 20 61 20 64 72 61 77 20 66 69 6c 65 20 28 |or a draw file (| 00000120 73 6f 20 79 6f 75 20 63 61 6e 20 68 61 76 65 20 |so you can have | 00000130 6c 6f 67 6f 20 0a 67 65 6e 65 72 61 74 65 64 20 |logo .generated | 00000140 6c 69 6e 65 61 72 74 20 69 6e 20 79 6f 75 72 20 |lineart in your | 00000150 44 54 50 20 64 6f 63 75 6d 65 6e 74 73 20 65 2e |DTP documents e.| 00000160 74 2e 63 2e 29 2e 54 68 65 20 69 6e 74 65 72 70 |t.c.).The interp| 00000170 72 65 74 65 72 20 0a 73 75 70 70 6f 72 74 73 20 |reter .supports | 00000180 6c 6f 6f 70 73 2c 20 73 75 62 72 6f 75 74 69 6e |loops, subroutin| 00000190 65 73 2c 20 63 6f 6d 6d 61 6e 64 20 61 62 62 72 |es, command abbr| 000001a0 65 76 69 61 74 69 6f 6e 73 20 61 6e 64 20 0a 65 |eviations and .e| 000001b0 78 70 72 65 73 73 69 6f 6e 73 20 28 74 68 6f 75 |xpressions (thou| 000001c0 67 68 20 6e 6f 74 20 76 61 72 69 61 62 6c 65 73 |gh not variables| 000001d0 29 2e 41 6c 6c 20 74 68 65 20 75 73 75 61 6c 20 |).All the usual | 000001e0 6c 6f 67 6f 20 63 6f 6d 6d 61 6e 64 73 20 0a 61 |logo commands .a| 000001f0 72 65 20 74 68 65 72 65 20 61 73 20 77 65 6c 6c |re there as well| 00000200 2c 20 6d 61 6b 69 6e 67 20 67 72 61 70 68 69 63 |, making graphic| 00000210 73 20 70 72 6f 67 72 61 6d 6d 69 6e 67 20 63 68 |s programming ch| 00000220 69 6c 64 73 70 6c 61 79 20 28 65 76 65 6e 20 0a |ildsplay (even .| 00000230 66 6f 72 20 62 69 67 20 6b 69 64 73 21 29 2e 0a |for big kids!)..| 00000240 0a 44 72 69 76 69 6e 67 20 61 20 62 75 67 67 79 |.Driving a buggy| 00000250 0a 0a 20 20 20 54 68 65 20 72 6f 62 6f 74 20 64 |.. The robot d| 00000260 72 69 76 65 72 20 70 72 6f 67 72 61 6d 20 61 6c |river program al| 00000270 73 6f 20 63 6f 6d 65 73 20 77 69 74 68 20 61 20 |so comes with a | 00000280 66 75 6c 6c 79 20 77 6f 72 6b 69 6e 67 20 0a 64 |fully working .d| 00000290 72 69 76 65 72 20 70 72 6f 67 72 61 6d 2c 20 69 |river program, i| 000002a0 6e 20 69 74 73 20 61 70 70 6c 69 63 61 74 69 6f |n its applicatio| 000002b0 6e 20 64 69 72 65 63 74 6f 72 79 20 28 75 6e 64 |n directory (und| 000002c0 65 72 20 74 68 65 20 66 69 6c 65 6e 61 6d 65 20 |er the filename | 000002d0 0a 32 4d 6f 74 6f 72 73 29 2e 54 68 69 73 20 64 |.2Motors).This d| 000002e0 72 69 76 65 72 20 77 6f 72 6b 73 20 77 69 74 68 |river works with| 000002f0 20 61 6e 20 41 63 6f 72 6e 20 55 73 65 72 20 70 | an Acorn User p| 00000300 6f 72 74 20 65 78 70 61 6e 73 69 6f 6e 20 63 61 |ort expansion ca| 00000310 72 64 20 0a 28 6f 6e 20 6d 79 20 41 33 30 30 30 |rd .(on my A3000| 00000320 29 20 74 6f 20 64 72 69 76 65 20 6d 79 20 73 69 |) to drive my si| 00000330 6d 70 6c 65 20 68 6f 6d 65 20 6d 61 64 65 20 62 |mple home made b| 00000340 75 67 67 79 20 28 4d 61 64 65 20 66 72 6f 6d 20 |uggy (Made from | 00000350 70 6c 61 6e 73 20 0a 69 6e 20 74 68 65 20 55 73 |plans .in the Us| 00000360 62 6f 72 6e 65 20 62 6f 6f 6b 20 52 4f 42 4f 54 |borne book ROBOT| 00000370 49 43 53 29 2e 49 20 68 61 76 65 20 64 65 73 69 |ICS).I have desi| 00000380 67 6e 65 64 20 6d 79 20 21 52 6f 62 6f 74 20 0a |gned my !Robot .| 00000390 61 70 70 6c 69 63 61 74 69 6f 6e 20 73 6f 20 61 |application so a| 000003a0 6e 79 6f 6e 65 20 63 61 6e 20 65 61 73 69 6c 79 |nyone can easily| 000003b0 20 72 65 77 72 69 74 65 20 74 68 65 20 62 61 73 | rewrite the bas| 000003c0 69 63 20 6c 69 62 72 61 72 79 20 66 69 6c 65 20 |ic library file | 000003d0 0a 22 44 72 69 76 65 72 22 20 77 69 74 68 20 74 |."Driver" with t| 000003e0 68 65 69 72 20 6f 77 6e 20 63 6f 64 65 20 74 6f |heir own code to| 000003f0 20 64 72 69 76 65 20 61 6e 79 20 62 75 67 67 79 | drive any buggy| 00000400 20 75 6e 64 65 72 20 74 68 65 20 0a 73 75 6e 2e | under the .sun.| 00000410 54 68 69 73 20 73 79 73 74 65 6d 20 61 6c 73 6f |This system also| 00000420 20 61 6c 6c 6f 77 73 20 66 6f 72 20 70 6c 65 61 | allows for plea| 00000430 6e 74 79 20 6f 66 20 66 75 74 75 72 65 20 65 78 |nty of future ex| 00000440 70 61 6e 73 69 6f 6e 2e 0a 0a 20 20 20 53 65 65 |pansion... See| 00000450 20 74 68 65 20 52 45 4d 20 6c 69 6e 65 73 20 69 | the REM lines i| 00000460 6e 20 74 68 65 20 62 61 73 69 63 20 66 69 6c 65 |n the basic file| 00000470 20 32 4d 6f 74 6f 74 73 20 66 6f 72 20 6d 6f 72 | 2Motots for mor| 00000480 65 20 64 65 74 61 69 6c 73 0a 0a 45 6e 74 65 72 |e details..Enter| 00000490 69 6e 67 20 50 72 6f 67 72 61 6d 73 0a 0a 20 20 |ing Programs.. | 000004a0 20 54 6f 20 63 72 65 61 74 65 20 61 20 6c 6f 67 | To create a log| 000004b0 6f 20 70 72 6f 67 72 61 6d 20 79 6f 75 20 6e 65 |o program you ne| 000004c0 65 64 20 74 6f 20 75 73 65 20 61 20 74 65 78 74 |ed to use a text| 000004d0 20 65 64 69 74 6f 72 20 73 75 63 68 20 61 73 20 | editor such as | 000004e0 0a 65 64 69 74 20 6f 72 20 31 73 74 20 77 6f 72 |.edit or 1st wor| 000004f0 64 20 70 6c 75 73 20 28 69 6e 20 6e 6f 6e 20 77 |d plus (in non w| 00000500 70 20 6d 6f 64 65 29 2e 4f 6e 63 65 20 79 6f 75 |p mode).Once you| 00000510 20 68 61 76 65 20 66 69 6e 69 73 68 65 64 20 0a | have finished .| 00000520 74 79 70 69 6e 67 20 69 6e 20 79 6f 75 72 20 70 |typing in your p| 00000530 72 6f 67 72 61 6d 20 63 68 65 63 6b 20 69 74 20 |rogram check it | 00000540 6f 76 65 72 20 74 68 6f 72 6f 75 67 68 6c 79 2c |over thoroughly,| 00000550 20 61 6e 64 20 6d 61 6b 65 20 73 75 72 65 20 0a | and make sure .| 00000560 74 68 61 74 20 65 76 65 72 79 20 73 74 61 74 65 |that every state| 00000570 6d 65 6e 74 20 69 6e 20 74 68 65 20 70 72 6f 67 |ment in the prog| 00000580 72 61 6d 20 69 73 20 73 65 70 61 72 61 74 65 64 |ram is separated| 00000590 20 62 79 20 65 69 74 68 65 72 20 61 20 61 20 0a | by either a a .| 000005a0 6e 65 77 2d 6c 69 6e 65 20 63 6f 64 65 20 28 26 |new-line code (&| 000005b0 30 44 29 20 6f 72 20 61 20 60 3a 60 20 63 68 61 |0D) or a `:` cha| 000005c0 72 61 63 74 65 72 2e 53 74 61 74 65 6d 65 6e 74 |racter.Statement| 000005d0 73 20 74 68 61 74 20 68 61 76 65 6e 60 74 20 0a |s that haven`t .| 000005e0 62 65 65 6e 20 73 65 70 61 72 61 74 65 64 20 70 |been separated p| 000005f0 72 6f 70 65 72 6c 79 20 77 69 6c 6c 20 67 65 6e |roperly will gen| 00000600 65 72 61 74 65 20 65 72 72 6f 72 73 20 77 68 65 |erate errors whe| 00000610 6e 20 79 6f 75 20 74 72 79 20 74 6f 20 72 75 6e |n you try to run| 00000620 20 0a 79 6f 75 72 20 70 72 6f 67 72 61 6d 20 69 | .your program i| 00000630 6e 20 74 68 65 20 69 6e 74 65 72 70 72 65 74 65 |n the interprete| 00000640 72 2e 0a 0a 54 68 65 20 6c 6f 67 6f 20 63 6f 6d |r...The logo com| 00000650 6d 61 6e 64 20 6c 69 6e 65 0a 0a 20 20 20 54 68 |mand line.. Th| 00000660 65 20 63 6f 6d 6d 61 6e 64 20 6c 69 6e 65 20 77 |e command line w| 00000670 69 6e 64 6f 77 20 69 6e 73 69 64 65 20 74 68 65 |indow inside the| 00000680 20 6c 6f 67 6f 20 61 70 70 6c 69 63 61 74 69 6f | logo applicatio| 00000690 6e 20 63 61 6e 20 62 65 20 0a 75 73 65 64 20 74 |n can be .used t| 000006a0 6f 20 65 78 65 63 75 74 65 20 73 75 62 72 6f 75 |o execute subrou| 000006b0 74 69 6e 65 73 20 28 62 79 20 74 79 70 69 6e 67 |tines (by typing| 000006c0 20 74 68 65 69 72 20 6e 61 6d 65 73 29 20 6f 72 | their names) or| 000006d0 20 61 6e 79 20 6e 6f 72 6d 61 6c 20 0a 6c 6f 67 | any normal .log| 000006e0 6f 20 63 6f 6d 6d 61 6e 64 2e 4e 6f 74 65 20 74 |o command.Note t| 000006f0 68 61 74 20 79 6f 75 20 63 61 6e 6e 6f 74 20 64 |hat you cannot d| 00000700 65 66 69 6e 65 20 54 4f 20 73 75 62 72 6f 75 74 |efine TO subrout| 00000710 69 6e 65 73 20 61 74 20 74 68 65 20 0a 63 6f 6d |ines at the .com| 00000720 6d 61 6e 64 20 6c 69 6e 65 2c 20 74 68 69 73 20 |mand line, this | 00000730 63 61 6e 20 6f 6e 6c 79 20 62 65 20 64 6f 6e 65 |can only be done| 00000740 20 75 73 69 6e 67 20 61 20 74 65 78 74 66 69 6c | using a textfil| 00000750 65 20 70 72 6f 67 72 61 6d 2e 54 68 65 20 0a 70 |e program.The .p| 00000760 72 6f 67 72 61 6d 20 73 65 61 72 63 68 65 73 20 |rogram searches | 00000770 74 68 65 20 63 75 72 72 65 6e 74 6c 79 20 6c 6f |the currently lo| 00000780 61 64 65 64 20 70 72 6f 67 72 61 6d 20 66 6f 72 |aded program for| 00000790 20 61 6e 79 20 6e 61 6d 65 20 79 6f 75 20 0a 74 | any name you .t| 000007a0 79 70 65 20 74 68 61 74 20 69 74 20 64 6f 65 73 |ype that it does| 000007b0 20 6e 6f 74 20 72 65 63 6f 67 6e 69 73 65 20 61 | not recognise a| 000007c0 73 20 6f 6e 65 20 6f 66 20 69 74 60 73 20 6f 77 |s one of it`s ow| 000007d0 6e 20 63 6f 6d 6d 61 6e 64 73 2c 20 6f 6e 6c 79 |n commands, only| 000007e0 20 0a 74 68 72 6f 77 69 6e 67 20 62 61 63 6b 20 | .throwing back | 000007f0 61 6e 20 65 72 72 6f 72 20 69 66 20 6e 6f 20 54 |an error if no T| 00000800 4f 20 73 75 62 72 6f 75 74 69 6e 65 20 63 61 6e |O subroutine can| 00000810 20 62 65 20 66 6f 75 6e 64 20 67 6f 69 6e 67 20 | be found going | 00000820 62 79 20 0a 74 68 61 74 20 6e 61 6d 65 0a 20 20 |by .that name. | 00000830 20 41 6e 79 20 6e 6f 72 6d 61 6c 20 6c 6f 67 6f | Any normal logo| 00000840 20 63 6f 6d 6d 61 6e 64 20 63 61 6e 20 62 65 20 | command can be | 00000850 75 73 65 64 20 61 74 20 74 68 65 20 63 6f 6d 6d |used at the comm| 00000860 61 6e 64 20 6c 69 6e 65 20 0a 28 66 6f 72 77 61 |and line .(forwa| 00000870 72 64 2c 62 61 63 6b 2c 6c 65 66 74 20 65 2e 74 |rd,back,left e.t| 00000880 2e 63 2e 29 2c 20 61 73 20 77 65 6c 6c 20 61 73 |.c.), as well as| 00000890 20 6c 6f 6f 70 73 20 61 6e 64 20 54 4f 20 73 75 | loops and TO su| 000008a0 62 72 6f 75 74 69 6e 65 20 0a 6e 61 6d 65 73 2e |broutine .names.| 000008b0 43 6f 6d 6d 61 6e 64 73 20 61 72 65 20 73 65 70 |Commands are sep| 000008c0 61 72 61 74 65 64 20 61 73 20 75 73 75 61 6c 20 |arated as usual | 000008d0 62 79 20 74 68 65 20 60 3a 60 20 63 68 61 72 61 |by the `:` chara| 000008e0 63 74 65 72 0a 0a 54 68 65 20 48 45 4c 50 20 66 |cter..The HELP f| 000008f0 75 6e 63 74 69 6f 6e 0a 20 0a 20 20 20 54 68 65 |unction. . The| 00000900 20 68 65 6c 70 20 66 75 6e 63 74 69 6f 6e 20 69 | help function i| 00000910 73 20 73 75 70 70 6f 72 74 65 64 20 61 73 20 61 |s supported as a| 00000920 20 77 69 6e 64 6f 77 20 61 76 61 69 6c 61 62 6c | window availabl| 00000930 65 20 62 79 20 0a 63 6c 69 63 6b 69 6e 67 20 6f |e by .clicking o| 00000940 6e 20 60 48 45 4c 50 60 20 69 6e 20 74 68 65 20 |n `HELP` in the | 00000950 70 72 6f 67 72 61 6d 73 20 6d 65 6e 75 20 74 72 |programs menu tr| 00000960 65 65 20 6f 72 20 62 79 20 74 79 70 69 6e 67 20 |ee or by typing | 00000970 48 45 4c 50 20 0a 66 6f 6c 6c 6f 77 65 64 20 62 |HELP .followed b| 00000980 79 20 74 68 65 20 6c 6f 67 6f 20 63 6f 6d 6d 61 |y the logo comma| 00000990 6e 64 20 79 6f 75 20 77 6f 75 6c 64 20 6c 69 6b |nd you would lik| 000009a0 65 20 68 65 6c 70 20 6f 6e 2e 0a 0a 50 72 6f 67 |e help on...Prog| 000009b0 72 61 6d 20 65 78 65 63 75 74 69 6f 6e 0a 0a 20 |ram execution.. | 000009c0 20 20 42 65 63 61 75 73 65 20 74 68 65 20 6c 6f | Because the lo| 000009d0 67 6f 20 69 6e 74 65 72 70 72 65 74 65 72 20 77 |go interpreter w| 000009e0 61 73 20 77 72 69 74 74 65 6e 20 69 6e 20 42 41 |as written in BA| 000009f0 53 49 43 2c 20 65 78 65 63 75 74 69 6f 6e 20 0a |SIC, execution .| 00000a00 69 73 20 6e 6f 74 20 61 73 20 66 61 73 74 20 61 |is not as fast a| 00000a10 73 20 69 74 20 6d 69 67 68 74 20 62 65 2e 41 6c |s it might be.Al| 00000a20 73 6f 20 74 68 65 20 77 69 6d 70 20 65 6e 76 69 |so the wimp envi| 00000a30 72 6f 6e 6d 65 6e 74 20 73 6c 6f 77 73 20 0a 64 |ronment slows .d| 00000a40 6f 77 6e 20 70 72 6f 67 72 61 6d 73 2c 20 61 73 |own programs, as| 00000a50 20 65 78 74 65 6e 73 69 76 65 20 72 65 64 72 61 | extensive redra| 00000a60 77 69 6e 67 20 6f 66 20 74 68 65 20 69 6e 74 65 |wing of the inte| 00000a70 72 70 72 65 74 65 72 73 20 64 69 73 70 6c 61 79 |rpreters display| 00000a80 20 0a 77 69 6e 64 6f 77 20 69 73 20 6e 65 63 65 | .window is nece| 00000a90 73 73 61 72 79 20 65 76 65 72 79 20 74 69 6d 65 |ssary every time| 00000aa0 20 74 68 65 20 74 75 72 74 6c 65 20 69 73 20 6d | the turtle is m| 00000ab0 6f 76 65 64 20 6f 72 20 61 20 6c 69 6e 65 20 69 |oved or a line i| 00000ac0 73 20 0a 64 72 61 77 6e 2e 54 6f 20 68 65 6c 70 |s .drawn.To help| 00000ad0 20 73 70 65 65 64 20 75 70 20 74 68 65 20 70 72 | speed up the pr| 00000ae0 6f 67 72 61 6d 73 20 65 78 65 63 75 74 69 6f 6e |ograms execution| 00000af0 2c 20 63 6c 6f 73 65 20 74 68 65 20 70 72 6f 67 |, close the prog| 00000b00 72 61 6d 73 20 0a 64 69 73 70 6c 61 79 20 61 6e |rams .display an| 00000b10 64 20 63 6f 6d 6d 61 6e 64 20 6c 69 6e 65 20 77 |d command line w| 00000b20 69 6e 64 6f 77 73 20 6c 65 61 76 69 6e 67 20 74 |indows leaving t| 00000b30 68 65 20 70 72 6f 67 72 61 6d 20 73 74 61 74 75 |he program statu| 00000b40 73 20 0a 77 69 6e 64 6f 77 20 6f 70 65 6e 20 6f |s .window open o| 00000b50 6e 6c 79 2c 20 74 6f 20 69 6e 64 69 63 61 74 65 |nly, to indicate| 00000b60 20 70 72 6f 67 72 61 6d 73 20 70 72 6f 67 72 65 | programs progre| 00000b70 73 73 69 6f 6e 2e 0a 0a 4c 6f 6f 70 73 0a 0a 20 |ssion...Loops.. | 00000b80 20 20 20 54 68 65 20 69 6e 74 65 72 70 72 65 74 | The interpret| 00000b90 65 72 20 75 73 65 73 20 61 20 73 74 61 63 6b 20 |er uses a stack | 00000ba0 73 79 73 74 65 6d 20 74 6f 20 6b 65 65 70 20 74 |system to keep t| 00000bb0 72 61 63 6b 20 6f 66 20 63 75 72 72 65 6e 74 20 |rack of current | 00000bc0 0a 6c 6f 6f 70 73 20 73 6f 20 79 6f 75 20 63 61 |.loops so you ca| 00000bd0 6e 20 6e 65 73 74 20 6c 6f 6f 70 73 20 61 74 20 |n nest loops at | 00000be0 74 68 65 20 63 6f 6d 6d 61 6e 64 20 6c 69 6e 65 |the command line| 00000bf0 20 6f 72 20 69 6e 73 69 64 65 20 79 6f 75 72 20 | or inside your | 00000c00 0a 70 72 6f 67 72 61 6d 73 2e 0a 20 20 20 20 54 |.programs.. T| 00000c10 68 65 20 73 74 72 75 63 74 75 72 65 20 6f 66 20 |he structure of | 00000c20 61 20 6c 6f 6f 70 20 69 73 20 61 73 20 66 6f 6c |a loop is as fol| 00000c30 6c 6f 77 73 20 3a 0a 0a 20 20 20 20 20 20 20 20 |lows :.. | 00000c40 5b 3c 6e 75 6d 62 65 72 20 6f 66 20 74 69 6d 65 |[<number of time| 00000c50 73 20 74 6f 20 65 78 65 63 75 74 65 20 74 68 65 |s to execute the| 00000c60 20 6c 6f 6f 70 3e 20 20 3c 3d 3d 20 73 74 61 72 | loop> <== star| 00000c70 74 20 6f 66 20 6c 6f 6f 70 0a 20 20 20 20 20 20 |t of loop. | 00000c80 20 20 46 4f 52 57 41 52 44 20 31 30 30 0a 20 20 | FORWARD 100. | 00000c90 20 20 20 20 20 20 52 49 47 48 54 20 39 30 20 20 | RIGHT 90 | 00000ca0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00000cb0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 3c 3d | <=| 00000cc0 3d 20 73 74 61 74 65 6d 65 6e 74 73 0a 20 20 20 |= statements. | 00000cd0 20 20 20 20 20 65 2e 74 2e 63 2e 0a 20 20 20 20 | e.t.c.. | 00000ce0 20 20 20 20 5d 20 20 20 20 20 20 20 20 20 20 20 | ] | 00000cf0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00000d00 20 20 20 20 20 20 20 20 20 20 20 20 3c 3d 3d 20 | <== | 00000d10 65 6e 64 20 6f 66 20 6c 6f 6f 70 20 20 20 20 20 |end of loop | 00000d20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 0a 54 | .T| 00000d30 72 79 20 74 68 65 20 66 6f 6c 6c 6f 77 69 6e 67 |ry the following| 00000d40 20 61 74 20 74 68 65 20 63 6f 6d 6d 61 6e 64 20 | at the command | 00000d50 6c 69 6e 65 3a 0a 0a 20 20 20 20 20 20 20 20 20 |line:.. | 00000d60 20 20 20 20 20 20 20 20 20 20 20 5b 32 34 3a 46 | [24:F| 00000d70 6f 72 77 61 72 64 20 35 30 3a 52 69 67 68 74 20 |orward 50:Right | 00000d80 31 35 3a 5d 0a 20 20 20 20 20 0a 20 20 20 54 68 |15:]. . Th| 00000d90 69 73 20 73 68 6f 72 74 20 73 74 61 74 65 6d 65 |is short stateme| 00000da0 6e 74 20 64 72 61 77 73 20 61 20 63 69 72 63 6c |nt draws a circl| 00000db0 65 20 62 79 20 72 65 70 65 61 74 69 6e 67 20 74 |e by repeating t| 00000dc0 68 65 20 0a 73 74 61 74 65 6d 65 6e 74 73 20 66 |he .statements f| 00000dd0 6f 72 77 61 72 64 20 31 30 30 20 61 6e 64 20 72 |orward 100 and r| 00000de0 69 67 68 74 20 31 35 20 74 77 65 6e 74 79 20 66 |ight 15 twenty f| 00000df0 6f 75 72 20 74 69 6d 65 73 2e 0a 0a 20 20 20 54 |our times... T| 00000e00 68 65 20 6c 6f 6f 70 69 6e 67 20 73 79 73 74 65 |he looping syste| 00000e10 6d 20 70 72 6f 76 69 64 65 64 20 69 73 20 61 20 |m provided is a | 00000e20 70 6f 77 65 72 66 75 6c 20 66 65 61 74 75 72 65 |powerful feature| 00000e30 20 6f 66 20 74 68 65 20 0a 69 6e 74 65 72 70 72 | of the .interpr| 00000e40 65 74 65 72 2c 20 61 6e 64 20 63 61 6e 20 62 65 |eter, and can be| 00000e50 20 75 73 65 64 20 74 6f 20 72 65 70 65 61 74 20 | used to repeat | 00000e60 61 6e 79 20 6c 6f 67 6f 20 63 6f 6d 6d 61 6e 64 |any logo command| 00000e70 20 6f 72 20 0a 63 6f 6d 6d 61 6e 64 73 20 73 65 | or .commands se| 00000e80 76 65 72 61 6c 20 74 69 6d 65 73 2e 20 20 0a 0a |veral times. ..| 00000e90 60 54 6f 60 20 73 75 62 72 6f 75 74 69 6e 65 73 |`To` subroutines| 00000ea0 0a 0a 20 20 20 54 68 65 20 69 6e 74 65 72 70 72 |.. The interpr| 00000eb0 65 74 65 72 20 68 61 73 20 70 72 6f 76 69 73 69 |eter has provisi| 00000ec0 6f 6e 73 20 66 6f 72 20 73 75 62 72 6f 75 74 69 |ons for subrouti| 00000ed0 6e 65 73 20 76 69 61 20 74 68 65 20 54 4f 20 61 |nes via the TO a| 00000ee0 6e 64 20 0a 45 6e 64 54 6f 20 63 6f 6d 6d 61 6e |nd .EndTo comman| 00000ef0 64 73 2e 41 20 73 75 62 72 6f 75 74 69 6e 65 20 |ds.A subroutine | 00000f00 74 61 6b 65 73 20 74 68 65 20 66 6f 72 6d 61 74 |takes the format| 00000f10 20 61 73 20 66 6f 6c 6c 6f 77 73 20 3a 0a 0a 20 | as follows :.. | 00000f20 20 20 54 4f 20 3c 6e 61 6d 65 20 6f 66 20 72 6f | TO <name of ro| 00000f30 75 74 69 6e 65 3e 20 3c 3d 3d 20 73 74 61 72 74 |utine> <== start| 00000f40 20 64 65 66 69 6e 69 6e 67 20 74 68 65 20 73 75 | defining the su| 00000f50 62 72 6f 75 74 69 6e 65 20 3c 6e 61 6d 65 3e 0a |broutine <name>.| 00000f60 20 20 20 46 4f 52 57 41 52 44 20 31 30 30 0a 20 | FORWARD 100. | 00000f70 20 20 52 49 47 48 54 20 39 30 20 20 20 20 20 20 | RIGHT 90 | 00000f80 20 20 20 20 20 3c 3d 3d 20 73 74 61 74 65 6d 65 | <== stateme| 00000f90 6e 74 73 0a 20 20 20 45 4e 44 54 4f 20 20 20 20 |nts. ENDTO | 00000fa0 20 20 20 20 20 20 20 20 20 20 3c 3d 3d 20 54 65 | <== Te| 00000fb0 6c 6c 73 20 6c 6f 67 6f 20 74 68 61 74 60 73 20 |lls logo that`s | 00000fc0 74 68 65 20 65 6e 64 20 6f 66 20 74 68 65 20 0a |the end of the .| 00000fd0 73 75 62 72 6f 75 74 69 6e 65 0a 20 20 20 20 54 |subroutine. T| 00000fe0 68 65 20 73 75 62 72 6f 75 74 69 6e 65 20 63 61 |he subroutine ca| 00000ff0 6e 20 74 68 65 6e 20 62 65 20 65 78 65 63 75 74 |n then be execut| 00001000 65 64 20 61 74 20 65 69 74 68 65 72 20 74 68 65 |ed at either the| 00001010 20 63 6f 6d 6d 61 6e 64 20 0a 6c 69 6e 65 20 6f | command .line o| 00001020 72 20 69 6e 73 69 64 65 20 74 68 65 20 70 72 6f |r inside the pro| 00001030 67 72 61 6d 20 62 79 20 74 79 70 69 6e 67 20 69 |gram by typing i| 00001040 74 73 20 6e 61 6d 65 20 6f 6e 6c 79 2e 0a 20 20 |ts name only.. | 00001050 20 4e 6f 74 65 20 73 75 62 72 6f 75 74 69 6e 65 | Note subroutine| 00001060 73 20 63 61 6e 6e 6f 74 20 62 65 20 64 65 66 69 |s cannot be defi| 00001070 6e 65 64 20 61 74 20 74 68 65 20 63 6f 6d 6d 61 |ned at the comma| 00001080 6e 64 20 6c 69 6e 65 2e 0a 0a 54 68 65 20 46 49 |nd line...The FI| 00001090 4e 49 53 48 20 63 6f 6d 6d 61 6e 64 0a 0a 20 20 |NISH command.. | 000010a0 20 54 68 69 73 20 63 6f 6d 6d 61 6e 64 20 73 74 | This command st| 000010b0 6f 70 73 20 74 68 65 20 65 78 65 63 75 74 69 6f |ops the executio| 000010c0 6e 20 6f 66 20 74 68 65 20 70 72 6f 67 72 61 6d |n of the program| 000010d0 20 63 75 72 72 65 6e 74 6c 79 20 0a 72 75 6e 6e | currently .runn| 000010e0 69 6e 67 2e 49 74 20 69 73 20 6e 65 65 64 65 64 |ing.It is needed| 000010f0 20 74 6f 20 70 72 65 76 65 6e 74 20 74 68 65 20 | to prevent the | 00001100 69 6e 74 65 72 70 72 65 74 65 72 20 63 61 72 72 |interpreter carr| 00001110 79 69 6e 67 20 6f 6e 20 61 73 20 69 74 20 0a 6e |ying on as it .n| 00001120 6f 72 6d 61 6c 6c 79 20 77 6f 75 6c 64 20 74 6f |ormally would to| 00001130 20 74 68 65 20 65 6e 64 20 6f 66 20 61 20 70 72 | the end of a pr| 00001140 6f 67 72 61 6d 2c 20 77 68 65 6e 20 61 20 70 72 |ogram, when a pr| 00001150 6f 67 72 61 6d 20 63 6f 6e 74 61 69 6e 73 20 0a |ogram contains .| 00001160 6f 6e 65 20 6f 72 20 6d 6f 72 65 20 54 4f 20 73 |one or more TO s| 00001170 75 62 72 6f 75 74 69 6e 65 20 64 65 66 69 6e 69 |ubroutine defini| 00001180 74 69 6f 6e 73 2c 20 61 73 20 69 66 20 74 68 65 |tions, as if the| 00001190 20 69 6e 74 65 72 70 72 65 74 65 72 20 0a 74 72 | interpreter .tr| 000011a0 69 65 73 20 74 6f 20 65 78 65 63 75 74 65 20 74 |ies to execute t| 000011b0 68 65 73 65 20 73 65 71 75 65 6e 74 69 61 6c 6c |hese sequentiall| 000011c0 79 20 61 6e 20 65 72 72 6f 72 20 77 69 6c 6c 20 |y an error will | 000011d0 62 65 20 67 65 6e 65 72 61 74 65 64 2e 0a 0a 54 |be generated...T| 000011e0 68 65 20 45 72 72 6f 72 20 6d 65 73 73 61 67 65 |he Error message| 000011f0 73 0a 0a 20 20 20 54 68 65 20 69 6e 74 65 72 70 |s.. The interp| 00001200 72 65 74 65 72 20 67 65 6e 65 72 61 74 65 73 20 |reter generates | 00001210 74 68 65 20 66 6f 6c 6c 6f 77 69 6e 67 20 65 72 |the following er| 00001220 72 6f 72 20 6d 65 73 73 61 67 65 73 20 77 68 69 |ror messages whi| 00001230 63 68 20 0a 61 72 65 20 64 69 73 70 6c 61 79 65 |ch .are displaye| 00001240 64 20 69 6e 20 69 74 73 20 63 6f 6d 6d 61 6e 64 |d in its command| 00001250 20 6c 69 6e 65 20 77 69 6e 64 6f 77 20 3a 0a 0a | line window :..| 00001260 20 20 20 42 61 64 20 6c 6f 67 6f 20 70 61 72 61 | Bad logo para| 00001270 6d 65 74 65 72 0a 20 20 20 4e 6f 20 73 75 63 68 |meter. No such| 00001280 20 73 75 62 72 6f 75 74 69 6e 65 0a 20 20 20 54 | subroutine. T| 00001290 6f 6f 20 6d 61 6e 79 20 54 4f 20 73 75 62 72 6f |oo many TO subro| 000012a0 75 74 69 6e 65 73 0a 20 20 20 4e 6f 74 20 69 6e |utines. Not in| 000012b0 20 61 20 54 4f 20 73 75 62 72 6f 75 74 69 6e 65 | a TO subroutine| 000012c0 0a 0a 20 20 20 54 68 65 73 65 20 6d 65 73 73 61 |.. These messa| 000012d0 67 65 73 20 72 65 66 6c 65 63 74 20 61 6e 20 65 |ges reflect an e| 000012e0 72 72 6f 72 20 69 6e 20 65 69 74 68 65 72 20 74 |rror in either t| 000012f0 68 65 20 75 73 65 72 73 20 70 72 6f 67 72 61 6d |he users program| 00001300 20 6f 72 20 0a 74 68 65 20 73 74 61 74 65 6d 65 | or .the stateme| 00001310 6e 74 20 6a 75 73 74 20 74 79 70 65 64 20 69 6e |nt just typed in| 00001320 20 61 74 20 74 68 65 20 63 6f 6d 6d 61 6e 64 20 | at the command | 00001330 6c 69 6e 65 20 77 69 6e 64 6f 77 2e 0a 0a 42 61 |line window...Ba| 00001340 63 6b 67 72 6f 75 6e 64 20 45 78 65 63 75 74 69 |ckground Executi| 00001350 6f 6e 0a 0a 20 20 20 45 78 65 63 75 74 69 6f 6e |on.. Execution| 00001360 20 6f 66 20 6c 6f 67 6f 20 70 72 6f 67 72 61 6d | of logo program| 00001370 73 20 74 61 6b 65 73 20 70 6c 61 63 65 20 69 6e |s takes place in| 00001380 20 74 68 65 20 62 61 63 6b 67 72 6f 75 6e 64 20 | the background | 00001390 28 76 69 61 20 0a 74 68 65 20 77 69 6d 70 60 73 |(via .the wimp`s| 000013a0 20 6e 75 6c 6c 20 72 65 61 73 6f 6e 20 63 6f 64 | null reason cod| 000013b0 65 29 2c 20 62 75 74 20 73 74 61 74 65 6d 65 6e |e), but statemen| 000013c0 74 73 20 61 74 20 74 68 65 20 63 6f 6d 6d 61 6e |ts at the comman| 000013d0 64 20 6c 69 6e 65 20 0a 74 61 6b 65 20 6f 76 65 |d line .take ove| 000013e0 72 20 74 68 65 20 6d 61 63 68 69 6e 65 20 64 75 |r the machine du| 000013f0 72 69 6e 67 20 74 68 65 69 72 20 65 78 65 63 75 |ring their execu| 00001400 74 69 6f 6e 2e 54 68 69 73 20 69 73 20 6e 6f 74 |tion.This is not| 00001410 20 6e 6f 72 6d 61 6c 6c 79 20 0a 6e 6f 74 69 63 | normally .notic| 00001420 65 61 62 6c 65 20 75 6e 6c 65 73 73 20 79 6f 75 |eable unless you| 00001430 20 68 61 76 65 20 65 6e 74 65 72 65 64 20 63 6f | have entered co| 00001440 6d 6d 61 6e 64 73 20 77 68 69 63 68 20 77 69 6c |mmands which wil| 00001450 6c 20 74 61 6b 65 20 73 6f 6d 65 20 0a 74 69 6d |l take some .tim| 00001460 65 20 74 6f 20 65 78 65 63 75 74 65 20 61 74 20 |e to execute at | 00001470 74 68 65 20 63 6f 6d 6d 61 6e 64 20 6c 69 6e 65 |the command line| 00001480 2e 54 6f 20 73 74 6f 70 20 61 20 63 6f 6d 6d 61 |.To stop a comma| 00001490 6e 64 20 64 75 72 69 6e 67 20 69 74 73 20 0a 65 |nd during its .e| 000014a0 78 65 63 75 74 69 6f 6e 20 61 74 20 74 68 65 20 |xecution at the | 000014b0 63 6f 6d 6d 61 6e 64 20 6c 69 6e 65 20 68 69 74 |command line hit| 000014c0 20 74 68 65 20 65 73 63 61 70 65 20 6b 65 79 20 | the escape key | 000014d0 61 20 66 65 77 20 74 69 6d 65 73 0a 0a 52 75 6e |a few times..Run| 000014e0 6e 69 6e 67 20 50 72 6f 67 72 61 6d 73 0a 0a 20 |ning Programs.. | 000014f0 20 20 50 72 6f 67 72 61 6d 73 20 63 61 6e 20 62 | Programs can b| 00001500 65 20 72 75 6e 20 62 79 20 65 69 74 68 65 72 20 |e run by either | 00001510 74 79 70 69 6e 67 20 60 52 55 4e 60 20 61 74 20 |typing `RUN` at | 00001520 74 68 65 20 6c 6f 67 6f 20 63 6f 6d 6d 61 6e 64 |the logo command| 00001530 20 0a 6c 69 6e 65 20 6f 72 20 62 79 20 63 6c 69 | .line or by cli| 00001540 63 6b 69 6e 67 20 6f 6e 20 52 55 4e 20 69 6e 20 |cking on RUN in | 00001550 74 68 65 20 70 72 6f 67 72 61 6d 20 73 74 61 74 |the program stat| 00001560 75 73 20 77 69 6e 64 6f 77 2e 54 68 69 73 20 0a |us window.This .| 00001570 77 69 6e 64 6f 77 20 63 61 6e 20 62 65 20 64 69 |window can be di| 00001580 73 70 6c 61 79 65 64 20 62 79 20 63 6c 69 63 6b |splayed by click| 00001590 69 6e 67 20 6f 6e 20 74 68 65 20 60 70 72 6f 67 |ing on the `prog| 000015a0 72 61 6d 60 20 6f 70 74 69 6f 6e 20 69 6e 20 0a |ram` option in .| 000015b0 74 68 65 20 69 6e 74 65 72 70 72 65 74 65 72 73 |the interpreters| 000015c0 20 6d 61 69 6e 20 6d 65 6e 75 20 74 72 65 65 2c | main menu tree,| 000015d0 20 74 68 6f 75 67 68 20 74 68 69 73 20 73 68 6f | though this sho| 000015e0 75 6c 64 20 6e 6f 74 20 6e 6f 72 6d 61 6c 6c 79 |uld not normally| 000015f0 20 0a 62 65 20 6e 65 63 65 73 73 61 72 79 2c 20 | .be necessary, | 00001600 61 73 20 74 68 65 20 69 6e 74 65 72 70 72 65 74 |as the interpret| 00001610 65 72 20 62 72 69 6e 67 73 20 75 70 20 74 68 65 |er brings up the| 00001620 20 73 74 61 74 75 73 20 77 69 6e 64 6f 77 20 61 | status window a| 00001630 73 20 0a 73 6f 6f 6e 20 61 73 20 61 20 70 72 6f |s .soon as a pro| 00001640 67 72 61 6d 20 69 73 20 6c 6f 61 64 65 64 2e 0a |gram is loaded..| 00001650 0a 4f 76 65 72 68 65 61 64 73 0a 0a 20 20 20 45 |.Overheads.. E| 00001660 76 65 72 79 20 74 69 6d 65 20 61 20 6c 6f 67 6f |very time a logo| 00001670 20 63 6f 6d 6d 61 6e 64 20 77 68 69 63 68 20 6d | command which m| 00001680 6f 76 65 73 20 74 68 65 20 74 75 72 74 6c 65 20 |oves the turtle | 00001690 69 73 20 65 78 65 63 75 74 65 64 2c 20 0a 74 68 |is executed, .th| 000016a0 65 20 69 6e 74 65 72 70 72 65 74 65 72 20 62 72 |e interpreter br| 000016b0 6f 61 64 63 61 73 74 73 20 61 20 6d 65 73 73 61 |oadcasts a messa| 000016c0 67 65 20 6f 76 65 72 20 74 68 65 20 77 69 6d 70 |ge over the wimp| 000016d0 20 6d 65 73 73 61 67 65 20 73 79 73 74 65 6d 20 | message system | 000016e0 0a 64 65 73 63 72 69 62 69 6e 67 20 74 68 65 20 |.describing the | 000016f0 63 6f 6d 6d 61 6e 64 20 6a 75 73 74 20 65 78 65 |command just exe| 00001700 63 75 74 65 64 2e 54 68 69 73 20 6d 65 73 73 61 |cuted.This messa| 00001710 67 65 20 77 69 6c 6c 20 6e 6f 72 6d 61 6c 6c 79 |ge will normally| 00001720 20 0a 62 65 20 69 6e 74 65 72 63 65 70 74 65 64 | .be intercepted| 00001730 20 62 79 20 61 20 72 6f 62 6f 74 20 64 72 69 76 | by a robot driv| 00001740 65 72 20 70 72 6f 67 72 61 6d 20 77 68 69 63 68 |er program which| 00001750 20 77 69 6c 6c 20 69 6e 20 74 75 72 6e 20 6d 6f | will in turn mo| 00001760 76 65 20 0a 61 20 74 75 72 74 6c 65 20 61 72 6f |ve .a turtle aro| 00001770 75 6e 64 2e 54 68 65 20 66 6f 72 6d 61 74 20 6f |und.The format o| 00001780 66 20 74 68 69 73 20 6d 65 73 73 61 67 65 20 69 |f this message i| 00001790 73 20 61 73 20 66 6f 6c 6c 6f 77 73 20 3a 0a 0a |s as follows :..| 000017a0 20 20 20 20 20 20 20 20 57 69 6d 70 20 70 6f 6c | Wimp pol| 000017b0 6c 20 63 6f 64 65 20 31 37 20 28 75 73 65 72 20 |l code 17 (user | 000017c0 6d 65 73 73 61 67 65 29 0a 0a 20 20 20 6d 65 73 |message).. mes| 000017d0 73 61 67 65 5f 62 6c 6f 63 6b 21 31 36 3d 26 34 |sage_block!16=&4| 000017e0 43 34 46 34 37 34 46 20 20 20 20 20 20 20 20 28 |C4F474F (| 000017f0 22 4c 4f 47 4f 22 20 69 6e 20 41 53 43 49 49 22 |"LOGO" in ASCII"| 00001800 29 0a 20 20 20 6d 65 73 73 61 67 65 5f 62 6c 6f |). message_blo| 00001810 63 6b 21 32 30 3d 63 6f 6d 6d 61 6e 64 20 6e 75 |ck!20=command nu| 00001820 6d 62 65 72 0a 20 20 20 6d 65 73 73 61 67 65 5f |mber. message_| 00001830 62 6c 6f 63 6b 2b 32 34 3d 6e 75 6d 65 72 69 63 |block+24=numeric| 00001840 20 73 74 72 69 6e 67 20 63 6f 6e 74 61 69 6e 69 | string containi| 00001850 6e 67 20 61 20 70 61 72 61 6d 65 74 65 72 0a 20 |ng a parameter. | 00001860 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00001870 20 20 20 74 6f 20 67 6f 20 77 69 74 68 20 74 68 | to go with th| 00001880 65 20 63 6f 6d 6d 61 6e 64 2e 0a 0a 20 20 20 54 |e command... T| 00001890 68 65 20 63 6f 6d 6d 61 6e 64 20 6e 75 6d 62 65 |he command numbe| 000018a0 72 73 20 61 72 65 20 61 73 20 66 6f 6c 6c 6f 77 |rs are as follow| 000018b0 73 20 3a 0a 20 20 0a 20 20 20 20 20 20 20 20 20 |s :. . | 000018c0 31 2e 20 46 6f 72 77 61 72 64 20 20 20 28 74 68 |1. Forward (th| 000018d0 65 20 70 61 72 61 6d 65 74 65 72 20 69 73 20 74 |e parameter is t| 000018e0 68 65 20 64 69 73 74 61 6e 63 65 29 0a 20 20 20 |he distance). | 000018f0 20 20 20 20 20 20 32 2e 20 42 61 63 6b 20 20 20 | 2. Back | 00001900 20 20 20 28 74 68 65 20 70 61 72 61 6d 65 74 65 | (the paramete| 00001910 72 20 69 73 20 74 68 65 20 64 69 73 74 61 6e 63 |r is the distanc| 00001920 65 29 0a 20 20 20 20 20 20 20 20 20 33 2e 20 4c |e). 3. L| 00001930 65 66 74 20 20 20 20 20 20 28 74 68 65 20 70 61 |eft (the pa| 00001940 72 61 6d 65 74 65 72 20 69 73 20 74 68 65 20 61 |rameter is the a| 00001950 6e 67 6c 65 20 69 6e 20 64 65 67 72 65 65 73 29 |ngle in degrees)| 00001960 0a 20 20 20 20 20 20 20 20 20 34 2e 20 52 69 67 |. 4. Rig| 00001970 68 74 20 20 20 20 20 28 74 68 65 20 70 61 72 61 |ht (the para| 00001980 6d 65 74 65 72 20 69 73 20 74 68 65 20 61 6e 67 |meter is the ang| 00001990 6c 65 20 69 6e 20 64 65 67 72 65 65 73 29 0a 20 |le in degrees). | 000019a0 20 20 20 20 20 20 20 20 35 2e 20 50 65 6e 75 70 | 5. Penup| 000019b0 20 20 20 20 20 28 6e 6f 20 70 61 72 61 6d 65 74 | (no paramet| 000019c0 65 72 29 0a 20 20 20 20 20 20 20 20 20 36 2e 20 |er). 6. | 000019d0 50 65 6e 44 6f 77 6e 20 20 20 28 6e 6f 20 70 61 |PenDown (no pa| 000019e0 72 61 6d 65 74 65 72 29 0a 20 20 20 20 20 20 20 |rameter). | 000019f0 20 20 37 2e 20 50 65 6e 43 6f 6c 6f 75 72 20 28 | 7. PenColour (| 00001a00 74 68 65 20 70 61 72 61 6d 65 74 65 72 20 69 73 |the parameter is| 00001a10 20 74 68 65 20 63 6f 6c 6f 75 72 20 30 2d 31 36 | the colour 0-16| 00001a20 29 0a 0a 20 20 20 55 73 69 6e 67 20 74 68 69 73 |).. Using this| 00001a30 20 6d 65 73 73 61 67 65 73 20 74 68 65 20 61 70 | messages the ap| 00001a40 70 6c 69 63 61 74 69 6f 6e 20 21 52 6f 62 6f 74 |plication !Robot| 00001a50 20 77 69 6c 6c 20 62 65 20 61 62 6c 65 20 74 6f | will be able to| 00001a60 20 0a 64 72 69 76 65 20 66 6c 6f 6f 72 20 74 75 | .drive floor tu| 00001a70 72 74 6c 65 73 20 76 69 61 20 61 20 6c 6f 67 6f |rtles via a logo| 00001a80 20 70 72 6f 67 72 61 6d 20 6f 72 20 63 6f 6d 6d | program or comm| 00001a90 61 6e 64 73 20 61 74 20 74 68 65 20 6c 6f 67 6f |ands at the logo| 00001aa0 20 0a 63 6f 6d 6d 61 6e 64 20 6c 69 6e 65 2e 50 | .command line.P| 00001ab0 72 65 73 65 6e 74 6c 79 20 74 68 65 20 21 52 6f |resently the !Ro| 00001ac0 62 6f 74 20 70 72 6f 67 72 61 6d 20 6f 6e 6c 79 |bot program only| 00001ad0 20 64 69 73 70 6c 61 79 73 20 6d 65 73 73 61 67 | displays messag| 00001ae0 65 73 20 0a 72 65 63 65 69 76 65 64 20 69 6e 20 |es .received in | 00001af0 69 74 73 20 77 69 6e 64 6f 77 73 2c 20 62 75 74 |its windows, but| 00001b00 20 49 20 68 61 76 65 20 6c 65 66 74 20 69 74 20 | I have left it | 00001b10 65 61 73 69 6c 79 20 61 6c 74 65 72 61 62 6c 65 |easily alterable| 00001b20 20 0a 28 6a 75 73 74 20 66 69 6c 6c 20 69 6e 20 | .(just fill in | 00001b30 74 68 65 20 62 6c 61 6e 6b 20 70 72 6f 63 65 64 |the blank proced| 00001b40 75 72 65 73 29 20 73 6f 20 74 68 61 74 20 49 20 |ures) so that I | 00001b50 63 61 6e 20 6d 61 6b 65 20 69 74 20 64 72 69 76 |can make it driv| 00001b60 65 20 0a 76 61 72 69 6f 75 73 20 62 75 67 67 79 |e .various buggy| 00001b70 60 73 20 61 6e 64 20 66 6c 6f 6f 72 20 74 75 72 |`s and floor tur| 00001b80 74 6c 65 73 20 61 74 20 61 20 6c 61 74 65 72 20 |tles at a later | 00001b90 64 61 74 61 2e 0a 0a 43 6f 6d 6d 65 6e 74 73 20 |data...Comments | 00001ba0 69 6e 73 65 72 74 65 64 20 69 6e 74 6f 20 70 72 |inserted into pr| 00001bb0 6f 67 72 61 6d 73 0a 0a 20 20 20 20 20 20 59 6f |ograms.. Yo| 00001bc0 75 20 63 61 6e 20 69 6e 73 65 72 74 20 61 6e 79 |u can insert any| 00001bd0 20 63 6f 6d 6d 65 6e 74 20 79 6f 75 20 6c 69 6b | comment you lik| 00001be0 65 20 69 6e 20 79 6f 75 72 20 41 53 43 49 49 20 |e in your ASCII | 00001bf0 74 65 78 74 20 0a 70 72 6f 67 72 61 6d 20 66 69 |text .program fi| 00001c00 6c 65 20 61 66 74 65 72 20 61 20 60 2f 60 20 63 |le after a `/` c| 00001c10 6f 6d 6d 61 6e 64 2e 54 68 69 73 20 63 6f 6d 6d |ommand.This comm| 00001c20 61 6e 64 20 62 65 68 61 76 65 73 20 6a 75 73 74 |and behaves just| 00001c30 20 6c 69 6b 65 20 0a 42 41 53 49 43 60 73 20 52 | like .BASIC`s R| 00001c40 45 4d 20 63 6f 6d 6d 61 6e 64 2e 0a 20 20 20 52 |EM command.. R| 00001c50 65 6d 65 6d 62 65 72 20 74 68 61 74 20 61 66 74 |emember that aft| 00001c60 65 72 20 79 6f 75 72 20 63 6f 6d 6d 65 6e 74 20 |er your comment | 00001c70 73 74 69 6c 6c 20 70 75 74 20 69 6e 20 61 20 60 |still put in a `| 00001c80 3a 60 20 63 68 61 72 61 63 74 65 72 20 0a 6f 72 |:` character .or| 00001c90 20 61 20 72 65 74 75 72 6e 20 63 6f 64 65 2c 20 | a return code, | 00001ca0 74 6f 20 73 65 70 61 72 61 74 65 20 69 74 20 66 |to separate it f| 00001cb0 72 6f 6d 20 74 68 65 20 6e 65 78 74 20 73 74 61 |rom the next sta| 00001cc0 74 65 6d 65 6e 74 2e 54 68 65 20 73 61 6d 65 20 |tement.The same | 00001cd0 0a 67 6f 65 73 20 66 6f 72 20 74 68 65 20 73 74 |.goes for the st| 00001ce0 61 74 65 6d 65 6e 74 20 62 65 66 6f 72 65 20 79 |atement before y| 00001cf0 6f 75 72 20 63 6f 6d 6d 65 6e 74 2e 0a 0a 54 68 |our comment...Th| 00001d00 65 20 62 61 73 69 63 20 6c 6f 67 6f 20 63 6f 6d |e basic logo com| 00001d10 6d 61 6e 64 73 0a 0a 46 6f 72 77 61 72 64 20 3c |mands..Forward <| 00001d20 64 69 73 74 61 6e 63 65 3e 20 4d 6f 76 65 73 20 |distance> Moves | 00001d30 79 6f 75 72 20 74 75 72 74 6c 65 20 66 6f 72 77 |your turtle forw| 00001d40 61 72 64 20 74 68 65 20 64 69 73 74 61 6e 63 65 |ard the distance| 00001d50 20 0a 73 70 65 63 69 66 69 65 64 20 62 79 20 79 | .specified by y| 00001d60 6f 75 20 69 6e 20 74 68 65 20 70 61 72 61 6d 65 |ou in the parame| 00001d70 74 65 72 20 66 6f 6c 6c 6f 77 69 6e 67 20 69 74 |ter following it| 00001d80 2e 0a 0a 42 61 63 6b 20 3c 64 69 73 74 61 6e 63 |...Back <distanc| 00001d90 65 3e 20 4d 6f 76 65 73 20 74 68 65 20 74 75 72 |e> Moves the tur| 00001da0 74 6c 65 20 62 61 63 6b 20 3c 64 69 73 74 61 6e |tle back <distan| 00001db0 63 65 3e 20 75 6e 69 74 73 0a 0a 4c 65 66 74 20 |ce> units..Left | 00001dc0 3c 61 6e 67 6c 65 3e 20 54 75 72 6e 73 20 74 68 |<angle> Turns th| 00001dd0 65 20 74 75 72 74 6c 65 20 61 6e 74 69 2d 63 6c |e turtle anti-cl| 00001de0 6f 63 6b 77 69 73 65 20 74 68 72 6f 75 67 68 20 |ockwise through | 00001df0 3c 61 6e 67 6c 65 3e 20 0a 64 65 67 72 65 65 73 |<angle> .degrees| 00001e00 0a 0a 52 69 67 68 74 20 3c 61 6e 67 6c 65 3e 20 |..Right <angle> | 00001e10 54 75 72 6e 73 20 74 68 65 20 74 75 72 74 6c 65 |Turns the turtle| 00001e20 20 63 6c 6f 63 6b 77 69 73 65 20 74 68 72 6f 75 | clockwise throu| 00001e30 67 68 20 3c 61 6e 67 6c 65 3e 20 64 65 67 72 65 |gh <angle> degre| 00001e40 65 73 0a 0a 50 65 6e 55 70 20 20 20 54 65 6c 6c |es..PenUp Tell| 00001e50 73 20 74 68 65 20 69 6e 74 65 72 70 72 65 74 65 |s the interprete| 00001e60 72 20 6e 6f 74 20 74 6f 20 64 72 61 77 20 6c 69 |r not to draw li| 00001e70 6e 65 73 0a 0a 50 65 6e 44 6f 77 6e 20 54 65 6c |nes..PenDown Tel| 00001e80 6c 73 20 74 68 65 20 69 6e 74 65 72 70 72 65 74 |ls the interpret| 00001e90 65 72 20 74 6f 20 64 72 61 77 20 6c 69 6e 65 73 |er to draw lines| 00001ea0 20 77 68 65 6e 20 74 68 65 20 74 75 72 74 6c 65 | when the turtle| 00001eb0 20 6d 6f 76 65 73 0a 0a 50 65 6e 43 6f 6c 6f 75 | moves..PenColou| 00001ec0 72 20 3c 63 6f 6c 6f 75 72 3e 20 54 65 6c 6c 73 |r <colour> Tells| 00001ed0 20 74 68 65 20 69 6e 74 65 72 70 72 65 74 65 72 | the interpreter| 00001ee0 20 74 6f 20 64 72 61 77 20 74 68 65 20 6c 69 6e | to draw the lin| 00001ef0 65 73 20 69 6e 20 0a 63 6f 6c 6f 75 72 20 3c 63 |es in .colour <c| 00001f00 6f 6c 6f 75 72 3e 20 20 20 0a 48 6f 6d 65 20 20 |olour> .Home | 00001f10 20 20 4d 6f 76 65 73 20 74 68 65 20 74 75 72 74 | Moves the turt| 00001f20 6c 65 20 62 61 63 6b 20 74 6f 20 69 74 73 20 68 |le back to its h| 00001f30 6f 6d 65 20 70 6f 73 69 74 69 6f 6e 20 61 6e 64 |ome position and| 00001f40 20 61 6e 67 6c 65 0a 0a 53 65 74 48 6f 6d 65 20 | angle..SetHome | 00001f50 54 61 6b 65 73 20 74 68 65 20 63 75 72 72 65 6e |Takes the curren| 00001f60 74 20 70 6f 73 69 74 69 6f 6e 20 61 6e 64 20 61 |t position and a| 00001f70 6e 67 6c 65 20 74 6f 20 62 65 20 74 68 65 20 74 |ngle to be the t| 00001f80 75 72 74 6c 65 73 20 0a 68 6f 6d 65 20 70 6f 73 |urtles .home pos| 00001f90 69 74 69 6f 6e 20 61 6e 64 20 61 6e 67 6c 65 0a |ition and angle.| 00001fa0 0a 43 6c 65 61 72 20 20 20 43 6c 65 61 72 73 20 |.Clear Clears | 00001fb0 74 68 65 20 6c 6f 67 6f 20 64 69 73 70 6c 61 79 |the logo display| 00001fc0 20 77 69 6e 64 6f 77 20 74 6f 20 74 68 65 20 64 | window to the d| 00001fd0 65 66 61 75 6c 74 20 77 68 69 74 65 0a 0a 52 65 |efault white..Re| 00001fe0 53 74 61 72 74 20 52 65 73 65 74 73 20 74 68 65 |Start Resets the| 00001ff0 20 65 6e 74 69 72 65 20 6c 6f 67 6f 20 64 69 73 | entire logo dis| 00002000 70 6c 61 79 20 28 6e 6f 74 20 74 68 65 20 70 72 |play (not the pr| 00002010 6f 67 72 61 6d 20 72 75 6e 6e 69 6e 67 29 0a 0a |ogram running)..| 00002020 41 6e 67 6c 65 20 3c 64 65 67 72 65 65 73 3e 20 |Angle <degrees> | 00002030 53 65 74 73 20 74 68 65 20 74 75 72 74 6c 65 60 |Sets the turtle`| 00002040 73 20 61 6e 67 6c 65 20 74 6f 20 3c 64 65 67 72 |s angle to <degr| 00002050 65 65 73 3e 0a 52 75 6e 20 20 20 54 65 6c 6c 73 |ees>.Run Tells| 00002060 20 74 68 65 20 69 6e 74 65 72 70 72 65 74 65 72 | the interpreter| 00002070 20 74 6f 20 62 65 67 69 6e 20 65 78 65 63 75 74 | to begin execut| 00002080 69 6e 67 20 74 68 65 20 63 75 72 72 65 6e 74 6c |ing the currentl| 00002090 79 20 0a 6c 6f 61 64 65 64 20 6c 6f 67 6f 20 74 |y .loaded logo t| 000020a0 65 78 74 66 69 6c 65 20 70 72 6f 67 72 61 6d 0a |extfile program.| 000020b0 0a 20 20 20 4d 6f 73 74 20 6c 6f 67 6f 20 63 6f |. Most logo co| 000020c0 6d 6d 61 6e 64 73 20 68 61 76 65 20 6d 69 6e 69 |mmands have mini| 000020d0 6d 75 6d 20 61 62 62 72 65 76 69 61 74 69 6f 6e |mum abbreviation| 000020e0 73 2c 20 77 68 69 63 68 20 63 61 6e 20 6d 61 6b |s, which can mak| 000020f0 65 20 0a 70 72 6f 67 72 61 6d 20 65 6e 74 72 79 |e .program entry| 00002100 20 65 61 73 69 65 72 2e 4d 61 6e 79 20 6e 75 6d | easier.Many num| 00002110 65 72 69 63 20 70 61 72 61 6d 65 74 65 72 73 20 |eric parameters | 00002120 63 61 6e 20 68 61 76 65 20 0a 6d 61 74 68 65 6d |can have .mathem| 00002130 61 74 69 63 61 6c 20 65 78 70 72 65 73 73 69 6f |atical expressio| 00002140 6e 73 20 75 73 65 64 20 69 6e 20 70 6c 61 63 65 |ns used in place| 00002150 20 6f 66 20 6a 75 73 74 20 6e 75 6d 62 65 72 73 | of just numbers| 00002160 20 74 68 6f 75 67 68 20 0a 76 61 72 69 61 62 6c | though .variabl| 00002170 65 73 20 61 72 65 20 6e 6f 74 20 73 75 70 70 6f |es are not suppo| 00002180 72 74 65 64 20 63 75 72 72 65 6e 74 6c 79 2e 41 |rted currently.A| 00002190 6c 73 6f 20 6e 6f 74 65 20 74 68 61 74 20 74 68 |lso note that th| 000021a0 65 20 6c 65 74 74 65 72 20 0a 63 61 73 65 20 6f |e letter .case o| 000021b0 66 20 74 68 65 20 63 6f 6d 6d 61 6e 64 73 20 64 |f the commands d| 000021c0 6f 73 65 6e 60 74 20 6d 61 74 74 65 72 2c 20 74 |osen`t matter, t| 000021d0 68 65 20 69 6e 74 65 72 70 72 65 74 65 72 20 77 |he interpreter w| 000021e0 69 6c 6c 20 0a 72 65 63 6f 67 6e 69 73 65 20 74 |ill .recognise t| 000021f0 68 65 20 63 6f 6d 6d 61 6e 64 20 65 69 74 68 65 |he command eithe| 00002200 72 20 77 61 79 2e 0a 0a 54 6f 20 66 69 6e 64 20 |r way...To find | 00002210 6f 75 74 20 61 20 63 6f 6d 6d 61 6e 64 73 20 61 |out a commands a| 00002220 62 62 72 65 76 69 61 74 69 6f 6e 20 75 73 65 20 |bbreviation use | 00002230 74 68 65 20 68 65 6c 70 20 77 69 6e 64 6f 77 20 |the help window | 00002240 0a 28 61 76 61 69 6c 61 62 6c 65 20 62 79 20 63 |.(available by c| 00002250 6c 69 63 6b 69 6e 67 20 6f 6e 20 68 65 6c 70 20 |licking on help | 00002260 69 6e 20 74 68 65 20 69 6e 74 65 72 70 72 65 74 |in the interpret| 00002270 65 72 73 20 6d 61 69 6e 20 6d 65 6e 75 20 0a 74 |ers main menu .t| 00002280 72 65 65 29 2e 4f 6e 63 65 20 74 68 65 20 77 69 |ree).Once the wi| 00002290 6e 64 6f 77 20 69 73 20 64 69 73 70 6c 61 79 65 |ndow is displaye| 000022a0 64 20 63 6c 69 63 6b 20 6f 6e 20 74 68 65 20 63 |d click on the c| 000022b0 6f 6d 6d 61 6e 64 20 79 6f 75 20 77 61 6e 74 20 |ommand you want | 000022c0 0a 74 6f 20 6b 6e 6f 77 20 61 62 6f 75 74 2e 0a |.to know about..| 000022d0 0a 44 65 62 75 67 67 69 6e 67 20 79 6f 75 72 20 |.Debugging your | 000022e0 70 72 6f 67 72 61 6d 0a 0a 20 20 20 44 65 62 75 |program.. Debu| 000022f0 67 67 69 6e 67 20 61 20 6c 6f 67 6f 20 70 72 6f |gging a logo pro| 00002300 67 72 61 6d 20 69 73 20 6d 61 69 6e 6c 79 20 75 |gram is mainly u| 00002310 70 20 74 6f 20 74 68 65 20 75 73 65 72 2c 20 68 |p to the user, h| 00002320 6f 77 65 76 65 72 20 74 68 65 20 0a 70 65 72 63 |owever the .perc| 00002330 65 6e 74 61 67 65 20 64 69 73 70 6c 61 79 20 69 |entage display i| 00002340 6e 20 74 68 65 20 70 72 6f 67 72 61 6d 20 73 74 |n the program st| 00002350 61 74 75 73 20 77 69 6e 64 6f 77 2c 20 63 6f 6e |atus window, con| 00002360 73 74 61 6e 74 6c 79 20 0a 75 70 64 61 74 65 64 |stantly .updated| 00002370 20 77 68 69 6c 73 74 20 61 20 70 72 6f 67 72 61 | whilst a progra| 00002380 6d 20 69 73 20 72 75 6e 2c 20 77 69 6c 6c 20 69 |m is run, will i| 00002390 6e 64 69 63 61 74 65 20 74 68 65 20 70 65 72 63 |ndicate the perc| 000023a0 65 6e 74 61 67 65 20 0a 74 68 72 6f 75 67 68 20 |entage .through | 000023b0 74 68 65 20 70 72 6f 67 72 61 6d 73 20 74 65 78 |the programs tex| 000023c0 74 66 69 6c 65 2c 20 74 68 65 20 63 6f 6d 6d 61 |tfile, the comma| 000023d0 6e 64 20 77 68 65 72 65 20 74 68 65 20 65 72 72 |nd where the err| 000023e0 6f 72 20 0a 6f 63 63 75 72 72 65 64 20 77 61 73 |or .occurred was| 000023f0 20 61 66 74 65 72 20 74 68 65 20 62 75 67 20 69 | after the bug i| 00002400 73 20 72 65 61 63 68 65 64 2e 0a 0a 20 20 20 49 |s reached... I| 00002410 20 68 61 76 65 20 66 6f 75 6e 64 20 61 20 63 6f | have found a co| 00002420 6d 6d 6f 6e 20 73 6f 75 72 63 65 73 20 6f 66 20 |mmon sources of | 00002430 65 72 72 6f 72 73 20 69 6e 20 70 72 6f 67 72 61 |errors in progra| 00002440 6d 73 20 61 72 65 20 65 69 74 68 65 72 20 0a 6d |ms are either .m| 00002450 69 73 74 79 70 65 64 20 63 6f 6d 6d 61 6e 64 73 |istyped commands| 00002460 20 28 67 65 6e 65 72 61 74 69 6e 67 20 60 4e 6f | (generating `No| 00002470 20 73 75 63 68 20 73 75 62 72 6f 75 74 69 6e 65 | such subroutine| 00002480 60 29 20 61 6e 64 20 6d 69 73 73 69 6e 67 20 0a |`) and missing .| 00002490 73 65 70 61 72 61 74 6f 72 73 20 62 65 74 77 65 |separators betwe| 000024a0 65 6e 20 73 74 61 74 65 6d 65 6e 74 73 20 28 67 |en statements (g| 000024b0 65 6e 65 72 61 74 69 6e 67 20 60 42 61 64 20 4c |enerating `Bad L| 000024c0 6f 67 6f 20 70 61 72 61 6d 65 74 65 72 60 29 2e |ogo parameter`).| 000024d0 0a 20 0a 0a |. ..| 000024d4
.