The Great Logo Atlas

The=20 Project...
Logo:=20 What is Logo?
The=20 Logo Tree
The Apple II Standard
- Summary=20 of Logo Features
- The=20 Authors
Live=20 implementations
Historic=20 implementations
Ana= lysis
Feature=20 Debate
Primitive=20 Glossary
Localisations
Manual=20 Repository
Links<= /A>

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Last update:
December 09. 2008 22:31:15

The Great Logo Atlas.

The=20 Project... > The Apple II Standard

The Apple II Standard

A SUMMARY OF APPLE LOGO=20 COMMANDS

Notes: The key to using Logo primitives is to = concentrate on=20 inputs and outputs as indicated in the top line of each definition. A = "#" sign=20 on the left means that the primitive can take any number of inputs if=20 parentheses are used.

These = lists need=20 to be formatted

Turtle Graphics

BACK One input (Distance). No outputs.
BK = Moves=20 turtle backward Distance steps.
Example: BACK 50

BACKGROUND No = inputs.=20 One output.
Outputs a number representing the color of the = background:
0=20 black; 1 white; 2 green; 3 violet; 4 orange; 5 blue; 6 black (for = b&w=20 TV).

CLEAN No inputs. No outputs.
Erases the graphics screen = without=20 affecting the turtle (unlike CLEARSCREEN).

CLEARSCREEN No inputs. = No=20 outputs.
CS Erases screen; centralizes turtle; initializes = heading
to 0=20 (north).

DOT One input (Position). No output.
Draws a dot of = the=20 current pen color at Position.
Example: DOT [100 0]
Places a dot = halfway=20 down the right edge of the screen.

FENCE No inputs. No = outputs.
Forces=20 turtle to remain within the bounds of the screen.
Example: FENCE FD=20 600
Gives error message "TURTLE OUT OF
BOUNDS" .

FORWARD = One input=20 (Distance). No outputs.
FD Moves turtle forward Distance = steps.
Example:=20 FORWARD 50

HEADING No inputs. One output.
Outputs turtle's = heading,=20 with north 0, east 90, south 180, and west 270.
Example: = HEADING
Outputs=20 45.

HIDETURTLE No inputs. No outputs.
HT Makes turtle=20 invisible.

HOME No inputs. No outputs.
Moves turtle to center = of=20 screen and sets heading
to O.

LEFT One input (Degrees). No=20 outputs.
LT Moves turtle to center of screen and sets heading=20 toO.
Example: LEFT 45
Turns the turtle 45 degrees left.

PEN = No=20 inputs. One output (List).
Outputs a two-word list. The first member = is=20 PENDOWN, PENERASE, PENUP, or PENREVERSE. The second member is the = color=20 number.
Example: PEN
Outputs [PENDOWN 2].

PENCOLOR . No = inputs. One=20 output (Number).
PC Outputs number representing current color: 0 = black; 1=20 white; 2 green; 3 violet; 4 orange; 5 blue.

PENDOWN No inputs. No = outputs.
PD Puts the turtle's pen down so it draws when=20 moved.

PENERASE No inputs. No outputs.
PE Puts the turtle's = eraser=20 down so that it erases when
moved.

PENREVERSE No inputs. No=20 outputs.
PX Interchanges pen color and background color, = draw
ing=20 where there aren't lines and erases where there
are.

PENUP No = inputs.=20 No outputs.
PU Lifts the pen up so no lines are drawn where = the
turtle=20 moves.

POS No inputs. One output (List).
Outputs the = coordinates of=20 the current position of
the turtle in the form [x,y].

RIGHT = Qne input=20 (Degrees). No outputs.
RT turns the turtle right (clockwise)=20 Degrees.
RIGHT 30
Turns the turtle 30 degrees = right.

SCRUNCH No=20 inputs. One output.
Outputs the aspect ratio, the ratio of vertical = turtle=20 step size to the horizontal one.

SETBG One input (Colornumber). = No=20 outputs.
Sets background color corresponding to=20 Color
number.

SETHEADING One input (Degrees). No = outputs.
SETH=20 Turns the turtle so it is heading in the = direction
Degrees.
Example:=20 SETHEADING - 45
Heads the turtle northwest.

SETPC One input=20 (Colornumber). No outputs.
Sets the color of the pen to Colornumber: = 0 black;=20 1 white; 2 green; 3 violet; 4 orange; 5 blue.

SETPEN One input = (Pair). No=20 outputs.
Sets pen state to Pair. The first word is PENDOWN, PENERASE, = PENUP,=20 or PENREVERSE. The second word is the color number.
Example: = SETPEN=20 [PENREVERSE 5]
Has the same effect as PENREVERSE SETPC = 5.

SETPOS One=20 input (Position). No outputs.
Moves the turtle to = Position.
Example:=20 SETPOS [1000]
Moves the turtle halfway down right edge of the=20 screen.

SETSCRUNCH One input (Ratio). No outputs.
Sets the = aspect=20 ratio to Ratio; changes YCOR accordingly.
Example: SETSCRUNCH = .75
Makes=20 vertical turtle step % the length of horizontal one.

SETX One = input (X).=20 No outputs.
Moves the turtle horizontally to x-coordinate X. Example: = SETX=20 100
Moves turtle horizontally to right edge of screen.

SETY = One input=20 (Y). No outputs.
Moves turtle vertically to y-coordinate Y. Example: = SETY -=20 100
Moves the turtle vertically to lower edge of = screen.

SHOWNP No=20 inputs. One output (Boolean).
Outputs TRUE ifturtle is shown; FALSE=20 otherwise.

SHOWTURTLE No inputs. No outputs.
ST Makes turtle=20 visible.

TOWARDS One input (Position). One output = (Heading).
Outputs=20 Heading to make turtle face Position.
Example: SETHEADING TOWARDS = [20 10]=20 Heads the turtle in the direction of position [20 10].

WINDOW No = inputs.=20 No outputs.
Makes the turtle field unbounded.
Example: = WINDOW
FD=20 600
PRINT POS
30.015 570.105

WRAP No inputs. No = outputs.
Makes=20 turtle field wrap around the edges of screen. Example: WRAP
FD = 700
PRINT=20 POS
30.01520.975

XCOR No inputs. One output.
Outputs the=20 x-coordinate of current position of turtle.

YCOR No inputs. One=20 output.
Outputs the y-coordinate of current position of = turtle.

Words and Lists -

ASCII One input (character). One=20 output.
Outputs the ASCII code for character.
See Appendix B for = the full=20 ASCII character set. Example: ASCII "D
Outputs 68

BUTFIRST One = input=20 (Object). One output.
BF Outputs all but the first element of=20 Object.
Example: BUTFIRST [NOW IS THE TIME]
Outputs IS THE=20 TIME.

BUTLAST One input (Object). One output.
BL Outputs all = but the=20 last element of Object.
Example: BUTLAST [NOW IS THE TIME] Outputs = NOW IS=20 THE.

CHAR One input (N). One output.
Outputs the character = whose ASCII=20 code is N. Example: CHAR 65
Outputs A.

COUNT One input (List). = One=20 output.
Outputs the number of elements in List.
Example: COUNT = [HOW MANY=20 ARE THERE] Outputs 4.

EMPTYP One input (Object). One = output.
Outputs=20 TRUE if Object is the empty word or the empty list; FALSE = otherwise.
Example:=20 EMPTYP 7
Outputs FALSE.

EQUALP Two inputs (Object!, Object2). = One=20 output.
Outputs TRUE if Object! and Object2 are equal; FALSE=20 otherwise.
Example: EQUALP 5 2 + 3
Outputs TRUE.

FIRST One = input=20 (Object). One output.
Outputs the first element of = Object.
Example: FIRST=20 [A B C]
Outputs A.

FPUT Two inputs (Object, List). One=20 output.
Outputs a new list formed by putting Object at the beginning = of the=20 List.
Example: FPUT "RAT [BAT HAT]
Outputs [RAT BAT = HAT].

ITEM Two=20 inputs (N, List). One output.
Outputs the Nth element of = List.
Example:=20 ITEM 2 [ROME CHICAGO MOSCOW] Outputs CHICAGO.

LAST One input = (Object).=20 One output.
Outputs the last element of Object.
Example: LAST [CAT = COW HEN=20 DOG]
Outputs DOG.

LIST Two inputs (Object!, = Object2).
Outputs a=20 list whose elements are Object! and Object2.
Example: LIST "HOUSE = [BARN=20 CABIN]
Outputs [HOUSE [BARN CABIN]]
# (LIST Object! Object2 = Object3 . .=20 .)

LISTP One input (Object). One output
Outputs TRUE if Object = is a=20 list, FALSE otherwise
Example: LISTP [HERE IS A LIST]
Outputs=20 TRUE.

LPUT Two inputs (Object, List). One output.
Outputs a = new list=20 formed by putting Object at the end of the List.
Example: LPUT "123 = [BAT=20 HAT]
Outputs [BAT HAT 123].

MEMBERP Two inputs (Item, List). = One=20 output.
Outputs TRUE if Item is a member of List, False otherwise. = Item may=20 be any data object.
Example: MEMBERP [1 2] [[A B] [1 2] [HI=20 THERE]]
Outputs TRUE.

NUMBERP One input (Object). One=20 output.
Outputs TRUE if Object is a number; FALSE = otherwise.
Example:=20 NUMBERP 5
Outputs TRUE.

SENTENCE Two inputs (Object!, = Object2). One=20 output (List).
SE Outputs a list made up of the words in Object!=20 and
Object2.
Example: SENTENCE [NOW IS][THE TIME] Outputs [NOW IS = THE=20 TIME].
# (SENTENCE Object!, Object2, Object3, . . .)

WORD Two = inputs=20 (Word I, Word2). One output (Word).
Outputs a word made up of Word I = and=20 Word2. Example: WORD "BAT'MAN
Outputs BATMAN.
# (WORD Word 1, = Word2,=20 Word3,...)

WORDP One input (Object). One output.
Outputs TRUE = if=20 Object is a word; FALSE otherwise.
Example: WORDP "XXX
Outputs = TRUE.

Variables

LOCAL One input (Name). No outputs.
Makes its = inputs local=20 to the procedure where LOCAL occurs.
# (Local Name1, Name2, Name3, . = .=20 .)

MAKE Two inputs (Object, Name). No output.
Gives the = variable Name=20 the value Object.
Example: MAKE "THIS 475
PR = :THIS
475

NAME Two=20 inputs (Object, Name). No outputs.
Gives variable Name the value=20 Object.
Example: NAME "MAN "JOHN
PR :MAN
JOHN.

NAMEP One = input=20 (Name). One output.
Outputs TRUE if name has a value; FALSE = otherwise.
PR=20 NAMEP "HOUSE
Outputs FALSE if HOUSE has not been assigned a=20 value.

THING One input (Name). One output.
Outputs the value = of the=20 variable Name.
Example: MAKE "SIZE 33
THING :SIZE
Outputs = 33

Arithmetic Operations

ARCTAN One input (N). One = output.
Outputs the=20 arctangent (inverse tangent) of N.
Example: ARCTAN 1
Outputs=20 45.

COS One input (N). One output.
Outputs the cosine of N=20 degrees.
Example: COS 60
Outputs .5.
INT One input (X). One=20 output.
Outputs the integer portion of X (truncates).
Example:=20 INT6.7
Outputs 6.

PRODUCT Two inputs (Nl, N2). One = output.
Outputs=20 the product of its inputs.
Example: PRODUCT 8 4
Outputs 32.
#=20 (PRODUCTNl, N2, N3, . . .).

QUOTIENT Two inputs (Xl, X2). One=20 output.
Outputs Xl divided by X2, truncated to an integer. =
Example:=20 QUOTIENT 18 4
Outputs 4.

RANDOM One input (N). One = output.
Outputs=20 a random non-negative integer less than N.
Example: RANDOM 6=20
OutputsO,1,2,3,4,or5.

REMAINDER Two inputs (Xl, X2). One=20 output.
Outputs the remainder obtained when Xl is divided by = Xl.
Example:=20 REMAINDER 17 5
Outputs 1.

RERANDOM Makes RANDOM produce the = same=20 sequences each
time.

ROUND One input (N). One = output.
Outputs N=20 rounded to the nearest integer.
Example: ROUND 5.501
Outputs=20 6.

SIN One input (N). One output.
Outputs the sine of N=20 degrees.
Example: Sin 30
Outputs .5.

SQRT One input (N). = One=20 output.
Outputs the square root of N, or error message if N is=20 negative.
Example: SQRT 36
Outputs 6.

SUM Two inputs (Xl, = Xl). One=20 output.
Outputs the sum of Xl and Xl.
Example: SUM 6 4
Outputs = 10.
#=20 (SUM Xl, Xl, X3, . . .)

+ Two inputs (Xl, Xl). One = output.
Outputs the=20 sum of its inputs.
Example: 4+5, 4 + 5,3+3+3
All output 9

- = Two=20 inputs (Xl, Xl). One output.
Outputs the result of Xl- = Xl.
Example: 5 - 3,=20 5 - 3, 5 - 3
All output 1

- One input (Xl). One = output.
Outputs the=20 negative of Xl.
Example: - 5
Outputs - 5

* Two inputs (Xl, = Xl). One=20 output.
Outputs the product of its inputs.
Example: 5*6, 5 * = 6
Both=20 output 30

/ Two inputs (Xl, Xl). One output.
Outputs Xl = divided by=20 Xl.
Example: 8/4, 8 / 4
Both output 1

> Two inputs (Xl, = Xl). One=20 output.
Outputs "TRUE if Xl is greater than Xl, "FALSE = otherwise.
Example:=20 5>4, 5 > 4
Both output "TRUE

< Two inputs (Xl, Xl). = One=20 output.
Outputs "TRUE if Xl is less than Xl, "FALSE = otherwise.
Example:=20 4<5, 4 < 5
Both output "TRUE

=3D Two inputs (Objectl, = Objectl).=20 One output.
Outputs "TRUE if Object 1 equals Objectl, "FALSE=20 otherwise.
Example: 4=3D4, 4 =3D 4, (FIRST "OTHELLO) =3D "0
All = output "TRUE

Conditionals and Flow of Control

CO One input (Object-optional). = No=20 outputs.
Resumes running a procedure after a PAUSE or CTRL-Z. If CO = has an=20 input, it becomes the output from PAUSE.

IF Inputs: (Pred,=20 Instructionlistl, Instructionlistl (optional=BB.
Outputs-whatever = instruction=20 list outputs (if any). If Pred is TRUE, runs Instructionlistl. If Pred = is FALSE,=20 runs Instructionlistl.
Example: IF (FIRST:NAMES) =3D "MITCH [PR [HI = MITCH]] [PR=20 [NOT HERE]]
Prints HI MITCH if condition is met.

IFFALSE One = input=20 (Instructionlist). Outputs: same as
IFF Instructionlist, if = any.
Runs=20 Instructionlist if result of most recent TEST was FALSE.

IFTRUE = One input=20 (Instructionlist). Outputs: same as
IFT Instructionlist, if = any.
Runs=20 Instructionlist if result of most recent TEST was = TRUE.
Example:
TEST :X=20 > 5
IFT [PR [THE NUMBER IS GREATER THAN 5]]
IFF [PR [GIVE ME A = BIGGER=20 NUMBER]]

OUTPUT One input (Object). One output (Object).
OP = Makes=20 Object the output of current procedure, and returns control to the = caller.=20
Example: OUTPUT :SIZE
Outputs the value of SIZE, which must now = be used=20 as input.

PAUSE No inputs. One output (Message).
Suspends = current=20 procedure and outputs Message.

REPEAT Two inputs (N, = Instructionlist).=20 Same outputs as Instructionlist, if any.
Runs Instructionlist N=20 times.
Example: REPEAT 3 [ FD 30 RT 120] Draws a triangle.

RUN = One=20 input (Instructionlist). Same outputs as Instructionlist, if = any.
Runs=20 Instructionlist as if typed directly.
Example:MAKE "COMMANDS [REPEAT = 6 [FD=20 50 RT 60]
RUN :COMMANDS
Draws a hexagon.

STOP No inputs. No = outputs.
Stops the current procedure and returns control to the=20 caller.

TEST One input (Pred). No outputs.
Stores value of = Fred (TRUE=20 or FALSE) for subsequent tests.
Example: See IFTRUE or = IFFALSE.

CTRL-G=20 No inputs. No output.
Stops current procedure, returns Logo to top = level, and=20 prints a ?

CTRL-W No inputs. No outputs.
Interrupts whatever = is=20 running. Typing any other character resumes what was = running.

CTRL-Z No=20 inputs. No outputs.
Interrupts whatever is running, causing a = PAUSE.

Logical Operations

AND Two inputs (Pred!, Pred2). One output = (TRUE=20 or
FALSE).
Outputs TRUE if Pred! and Pred2 are true; FALSE = otherwise.
#=20 (ANDPred!,Pred2,Pred3,.. .).
Example: AND :X>5 :X<1O
Outputs = TRUE if=20 X is between 5 and 10.

NOT One input (Pred). One output (TRUE or=20 FALSE).
Outputs TRUE if Fred is FALSE; TRUE otherwise. Example: NOT = EQUAL"=20 ABC" 123
Outputs TRUE.

OR Two inputs (Pred!, Pred2). One = output (TRUE=20 or
FALSE).
Outputs FALSE if both inputs are false. TRUE otherwise. = (OR=20 (Predl, Pred2, Pred3 . . . .)
# Example: OR :X <5 :X> = 10
Outputs=20 "TRUE if X is outside of 5-10.

The Outside World

BUTTONP One input (Paddlenumber). One output = (TRUE=20 or
FALSE).
Outputs TRUE if button on Paddlenumber is down; FALSE=20 otherwise.

KEYP No inputs. One output (TRUE or FALSE).
Outputs = TRUE if=20 there is at least one character waiting to be read; FALSE=20 otherwise.

PADDLE One input (Paddlenumber). One = output.
Outputs number=20 between 0 and 255 representing the rotation of the dial on the specified = paddle.

PRINT One input (Object). No outputs.
PR Prints its = input on=20 the screen, followed by a return.
# (PRINTObjectl Object2 . . = .).
Example:=20 (PR [THE NUMBER IS] :X)
Prints THE NUMBER IS 7 if the value of X is=20 7.

READCHAR No inputs. One output.
RC Outputs the first = character=20 typed. Waits for
character.
Example: MAKE" ANS RC

READLIST = No=20 inputs. One output.
RL Waits for the user to type a line, and outputs = in=20 list
form.
Example: MAKE" ANS RL

SHOW One input (Object). = No=20 output.
Prints Object on the screen, followed by a = return.

TYPE One=20 input (object). No output.
Prints its input on the screen without a=20 return.
# (TYPE 23 "HELLO [SKIDDOO]
Example: TYPE [THE PRODUCT OF = X*y=20 IS]
PRINT :X*:Y

WAIT One input (number). No outputs.
Causes = Logo to=20 pause for number/60 seconds.
WAIT 120

Text and Screen Commands

CLEARTEXT No inputs. No = outputs.
Clears text=20 screen and initializes cursor position.

CURSOR No inputs. One=20 output.
Outputs list of column and line numbers of=20 cursor
position.

FULLSCREEN Devotes the screen to graphics, = with=20 turtle field
showing.

SETCURSOR One input (Position). No=20 output.
Sets the cursor to Position (Lines 0--23, cols. 0--39). =
Example:=20 SETCURSOR [0 12]
Puts cursor halfway down the left edge of=20 the
screen.

SPLITSCREEN Devotes top 20 lines of screen to = turtle=20 field. TEXTSCREEN Devotes the entire screen to text.

CTRL-L = Devotes the=20 entire screen to graphics.
CTRL-S Devotes the top 20 lines of the = screen to=20 graphics.
CTRL- T Devotes the entire screen to text.

Workspace Management

BURY One input (Packagename). No = outputs.
Buries=20 all procedures and names in Package.

ERALL Optional input = (Package or=20 Packagelist). No output.
Erases all unburied procedures and variables = (in
Package or Packagelist) from the workspace.

ERASE One = input (Name=20 or Namelist). No outputs.
Erases the named procedure(s) from the = workspace.=20
Example: ERASE [CIRCLE PENT]
Erases the CIRCLE and PENT=20 procedures

ERN One input (Name or Namelist). No = outputs.
Erases the=20 named variable(s) from workspace. Example: ERN [VI v2]
Erases VI and = V2=20 variables.

ERNS Optional input (Package or Packagelist). No=20 outputs.
Erases all variables (in Package or Packagelist) from=20 workspace.

ERPS Optional input (Package or = Packagelist).
Erases all=20 procedures (in Package or Packagelist) from workspace.

PACKAGE = Two inputs=20 (Package, Name or Namelist). No outputs.
Puts each named procedure in = Package.
Example: PACKAGE "ANIMAL [CAT DOG]
Puts CAT and DOG in = the=20 package ANIMAL.

PKGALL One input (Package). No outputs.
Puts = into=20 Package all procedures and variables that are not already in = packages.

PO=20 One input (Name or Namelist). No outputs.
Prints the definitions of = the named=20 procedure(s).

POALL Optional input (Package or = Packagelist).
Prints=20 definition of every procedure and value of every variable (in Package or = Packagelist).

PONS Optional input (Package or Packagelist). No=20 outputs.
Prints the name and value of every variable (in Package or=20 Packagelist).

POPS Optional input (Package or Packagelist). No=20 outputs.
Prints the definition of every procedure in Package or=20 Packagelist.

POTS Optional input (Package or Packagelist). No=20 outputs.
Prints the title line of every procedure (in Package or=20 Packagelist).

UNBURY One input (Package). No outputs.
Unburies = all=20 procedures and names in Package.

Files

CATALOG No inputs. No outputs.
Outputs the names of the = N files=20 on the disk.

DISK No inputs. One output.
Outputs list of 3 = numbers:=20 the disk drive number, the slot number of the disk drive, and the volume = number=20 of the disk most recently used for

CATALOG or set with=20 SETDISK.

ERASEFILE One input (File). No outputs.
Erases File = named=20 "FILE.Logo from disk. Example: ?ERASEFILE "NOTES
- Erases file named=20 NOTES.LOGO.

LOAD One or two inputs (File, Package (optional=BB. = No=20 outputs.
Loads the contents of FILE.LOGO into the workspace. If = Package=20 is input, it specifies the package everything goes into.
Example: = LOAD=20 "TURTLESTUFF
Loads file called TURTLESTUFF.LOGO into = workspace.

SAVE=20 One or two inputs (File, Package (optional=BB. No outputs.
Creates a = file named=20 FILE. LOGO and saves all procedures and variables in Package if = this is=20 input, and of the entire workspace otherwise.
Example: SAVE=20 "TURTLESTUFF
Saves workspace contents in file called TURTLESTUFF.=20 LOGO

SETDISK One to three inputs (Drive, Slot, Volume (last=20 2
optional) . No outputs.
Sets the disk drive to Drive, slot to = Slot, and=20 volume to Volume.
Files

CATALOG No inputs. No = outputs.
Prints the=20 names of all files on the disk.

DISK No inputs. One output. = Outputs list=20 of 3 numbers: the disk drive number, the slot number of the disk drive, = and the=20 volume number of the disk most recently used for CATALOG or set = with=20 SETDISK.

ERASEFILE One input (File). No outputs.
Erases File = named=20 FILE. LOGO from disk. Example: ?ERASEFILE "NOTES
Erases file named=20 NOTES.LOGO.

LOAD One or two inputs (File, Package (optional=BB. = No=20 outputs.
Loads the contents of FILE.LOGO into the workspace. If = Package=20 is input, it specifies the package everything goes into.
Example: = LOAD=20 "SQUARE
Loads the file named SQUARE. LOGO from the disk to the=20 workspace.

SAVE One or two inputs (File, Package (optional=BB. No = outputs.
Creates a file named FILE. LOGO and saves all = procedures and=20 variables in Package if this is input, and of the entire workspace=20 otherwise.
Example: SAVE "SQUARE
Saves all the workspace contents = in a=20 file called SQUARE.LOGO.

SETDISK One to three inputs (Drive, = Slot, Volume=20 (last 2
optional). No outputs.
Sets the disk drive to Drive, slot = to Slot,=20 and volume to Volume.

Advanced Primitives or Rarely Used Primitives

GPROP Two inputs = (Name,=20 Prop). One output.
Outputs the value of Prop property of Name. = Example: GPROP=20 "CITY" A4
Outputs SAN FRANCISCO (see below PPROP for = reason).

PLIST=20 One input(Name). One output.
Outputs the property list associated = with=20 Name.

PPROP Three inputs (Name, Prop, Object). No = outputs.
Gives Name=20 the property Prop with value Object. Example: PPROP "CITY" A4 [SAN=20 FRANCISCO]
Gives the value of SAN FRANCISCO to the name A4 in = the=20 property list CITY.

PPS Optional input (Package or Packagelist).=20 Variable
outputs.
Prints the property list(s) of everything (in = Package or=20 Packagelist) in workspace.

REMPROP Two inputs (Name, Prop). No=20 outputs.
Removes property pair Prop from the property list of=20 Name.
Example: REMPROP "CITY" A4
Removes the name A4 and its value = from=20 the property list CITY.

CATCH Two inputs (Name, = Instructionlist).=20 Same outputs as
Instructionlist.
Runs Instructionlist. If a THROW = Name is=20 called while Instructionlist is run, control returns to the = CATCH.

ERROR=20 No inputs. One output.
Outputs six-element list containing = information about=20 the most recent error which has not had a message printed or output by=20 ERROR.

THROW One input (Name). No outputs.
Used to match name = with=20 CATCH name--error if none exists.

COPYDEF Two inputs (Newname, = Name). No=20 outputs.
Copies the definition of Name to that for Newname. =
Example:=20 COPYDEF "F "FORWARD
Gives the same definition as = FORWARD.

DEFINE Two=20 inputs (Name, List). No outputs.
Makes List the definition of the = procedure=20 Name. First list in List must be the inputs to Name. Example: DEFINE = "BOX=20 [[SIZE] [REPEAT 4 [FD :SIZE RT 90]]]

PRIMITIVEP One input (Name). = One=20 output.
Outputs TRUE if Name is name of primitive; FALSE=20 otherwise.
Example: PRIMITIVEP "FORWARD
Outputs TRUE

TEXT = One input=20 (Name). One output.
Outputs the definition of Name as a list of=20 lists.

GO One input (Name). No outputs.
Used to loop back to=20 instruction following LABEL.
Example: TO COUNTUP
MAKE "X = 1
LABEL=20 "LOOP
PRINT :X
MAKE "X :X + 1
GO "LOOP
END
It is better = to use=20 recursion than to use GO like this.

LABEL One input (Name). No=20 outputs.
Used to pass control to instruction using GO.

NODES = No=20 inputs. One output.
Outputs the number of free nodes.

RECYCLE = No=20 inputs. No outputs.
Frees as many nodes as possible through a=20 garbage
collection.

REPARSE Makes reparsing happen=20 immediately.

. BPT No input. No output.
Enters the Apple = monitor. Logo=20 may be resumed by typing 803G followed by RETURN.
.
CONTENTS = Outputs list=20 of currently defined objects, including
variables, procedures, Logo=20 primitives.

. DEPOSIT Two inputs (N,A). No outputs.
Writes A = into=20 machine address N.
.
EXAMINE One input (Object). One = output.
Outputs=20 the contents of machine address Object (decimal) if Object is a number.=20 Otherwise, outputs the address of the first node of Object.

. = PRINTER One=20 input (N). No outputs.
Message to Logo that any subsequent = information=20 displayed on the screen is to be printed.
Example: .PRINTER 1
If = printer=20 card is in slot # I, sends text to printer. yse .PRINTER 0 to return off = printer=20 and to return to screen.

Control Characters

CTRL-A Moves cursor to beginning of = line.
CTRL-B=20 Moves cursor back one character.
CTRL-C Exits editor, saving changes=20 made.
CTRL-D Deletes character under cursor.
CTRL-E Moves cursor = to end of=20 line.
CTRL-F Moves cursor forward one character.
CTRL-G Emergency = STOP,=20 aborts procedure or editing.
CTRL-H Same as left arrow.
CTRL-K = Kills all=20 text to right of cursor.
CTRL-L Scrolls screen so current line is at = center=20 (editor).
Same as FULLSCREEN (command level).
CTRL-M Same as=20 (RETURN).
CTRL-N Moves cursor down one line.
CTRL-O Opens a new = line at=20 position of cursor.

CTRL-P Moves cursor up one line.
CTRL-Q = Allows=20 insertion of delimiting characters.
CTRL-S Same as = SPLITSCREEN.
CTRL- T=20 Same as TEXTSCREEN.
CTRL-U Same as right arrow.
CTRL-V Scrolls = cursor down=20 text one page.
CTRL-W Temporary stop. Any other key resumes=20 program.
Helpful to stop screen scroll.
CTRL-Y Inserts previous = line=20 erased with CTRL-K.
Useful for moving a line in the editor.
CTRL-Z = Same as=20 PAUSE, except that used during a
program.

ESC > Moves = cursor to end=20 of editor buffer.
ESC < Moves cursor to beginning of editor = buffer.

Editing Primitives

EDIT One input (Name, Namelist). No = output.
ED=20 Starts up LOGO editor.
Use CTRL-C to leave editor, saving changes. = Example:=20 ED "BOX

EDNS Zero or one input (Package, Package list).=20 No
outputs.
With no input, puts all variables in editor.
With = Package=20 input, puts all variables in package in editor.
With Package list as = input,=20 puts all variables in list in editor.

TO One input = (Name-unquoted). No=20 output
Enters procedure editor.
Use END to complete procedure = definition.=20 Example: TO BOX

Error Messages

Apple Logo has 42 error messages for your = convenience.=20 Here is a complete list of the error messages. (Only in = Ref:(2))

Number=20 Message
1 (procedure) IS ALREADY DEFINED
2 NUMBER TOO BIG
3 = (symbol)=20 ISN'T A PROCEDURE
4 (symbol) ISN'T A WORD
5 (procedure) CAN'T BE = USED IN A=20 PROCEDURE
6. (symbol) IS A PRIMITIVE
7 CAN'T FIND LABEL = (symbol)
8=20 CAN'T (symbol) FROM THE EDITOR
9 (symbol) IS UNDEFINED
10 = (procedure)=20 DIDN'T OUTPUT TO (symbol)
11 I'M HAVING TROUBLE WITH THE DISK
12 = DISK=20 FULL
13 CAN'T DIVIDE BY ZERO
14 END OF DATA
15 FILE ALREADY=20 EXISTS
16 FILE LOCKED
17 FILE NOT FOUND
18 FILE IS WRONG = TYPE
19 TOO=20 FEW ITEMS IN (list)
20 NO MORE FILE BUFFERS
21 CAN'T FIND CATCH = FOR=20 (symbol)
22 (symbol) NOT FOUND
23 OUT OF SPACE
24 (procedure) = CAN'T BE=20 USED IN PROCEDURE
25 (symbol) IS NOT TRUE OR FALSE
26 PAUSING. . = .
27=20 YOU'RE AT TOPLEVEL
28 STOPPED!
29 NOT ENOUGH INPUTS TO = (procedure)
30=20 TOO MANY INPUTS TO (procedure)
31 TOO MUCH INSIDE PARENTHESIS
32 = TOO FEW=20 ITEMS IN (list)
33 CAN ONLY DO THAT IN A PROCEDURE
34 TURTLE OUT = OF=20 BOUNDS
35 I DON'T KNOW HOW TO (symbol)
36 (symbol) HAS NO = VALUE
37 )=20 WITHOUT (
38 I DON'T KNOW WHAT TO DO WITH (symbol)
39 DISK VOLUME=20 MISMATCH
40 DISK IS WRITE PROTECTED
41 (procedure) DOESN'T LIKE = (symbol)=20 AS INPUT
42 (procedure) DIDN'T OUTPUT

Alphabetical Listing of Logo Primitives

AND=20
ARCTAN
ASCII
BACK
BACKGROUND
BURY
BUTFIRST =
BUTLAST=20
BUTTONP
CATALOG
CATCH
CHAR
CLEAN
CLEARSCREEN=20
CLEARTEXT
CO
COPYDEF
COS
COUNT
CURSOR
DEFINE=20
DEFINEDP
DISK
DOT
EDIT
EDNS
EMPTYP =
EQUALP
ERALL=20
ERASE
ERASEFILE
ERN
ERNS
ERPS
ERROR
FENCE =
FIRST=20
FORWARD
FPUT
FULLSCREEN
GPROP
GO
HEADING =
HIDETURTLE=20
HOME
IF
IFFALSE =
IFTRUE
INT
ITEM
KEYP
LABEL
LAST=20
LEFT
LIST
LlSTP
LOAD
LOCAL
LPUT
MAKE
MEMBERP =
NAME=20
NAMEP
NODES
NOT
NUMBERP
OR
OUTPUT
PACKAGE =
PADDLE=20
PAUSE
PEN
PENCOLOR
PENDOWN
PENERASE
PENREVERSE =
PENUP=20
PKGALL
PLiST
PO
POALL
PONS
POPS
POS
POTS=20
PPROP
PPS
PRIMITIVEP
PRINT
PRODUCT
QUOTIENT =
RANDOM=20
READCHAR
READLIST
RECYCLE
REMAINDER
REMPROP=20
REPARSE
REPEAT
RERANDOM
RIGHT
ROUND
RUN
SAVE =
SCRUNCH=20
SENTENCE
SETBG
SETCURSOR
SETDISK
SETHEADING =
SETPC=20
SETPEN
SETPOS
SETSCRUNCH
SETX
SETY
SHOW =
SHOWNP=20
SHOWTURTLE
SIN
SPLITSCREEN =
SQRT
STOP
SUM
TEST
TEXT=20
TEXTSCREEN
THING
THROW
TO
TOWARDS =
TYPE
UNBURY
WAIT=20
WINDOW
WORD
WORDP
WRAP
XCOR=20
YCOR

Providence:
Scanned from:

(1) 88 Apple Logo = Programs:=20 Mitchell Waite, Donald Martin, Jennifer Ann Martin. SAMS. The Waite = Group 1984.=20 ISBN0-672-22343-0

And also in (2) Apple Logo Programming Primer: = Donald=20 Martin, Stephen Prata, Marijane Paulsen.SAMS. The Waite Group 1984.=20 ISBN0-672-22342-2

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