Commands Overview by Group

This page contains an extensive listing of all Logo commands, global names and operators, sorted by group.

Arrays

Create and manipulate arrays.

AGET	Reports the value of an array element.
ARRAY	Creates an array.
ARRAY?	Reports TRUE if the object is an array.
ARRAYDIMS	Reports the structure of an array.
ASET	Sets the value of an array element.
FILLARRAY	Sets the values of an array.
LISTARRAY	Reports the values of an array as a list.
SETARRAYDIMS	Sets the structure of an array.
TEXTARRAY	Outputs the structure of an array as a word.

Logo Colors

Create and work with colors

ALPHA	Reports the first active turtle’s alpha value.
BACKGROUND	Reports the background color.
BGPATTERN	Reports the background pattern.
COLOR	Reports the color for a name or value if possible.
COLORINDEX	Coerces a color value to a basic Logo color number.
COLORNAME	Reports the name of a color if possible.
COLORS	Reports a list of available color names.
PATTERN	Reports the turtle’s pattern.
PENCOLOR	Reports the pen color.
SETALPHA	Sets the default transparency value for colors.
SETBG	Sets the background color.
SETBGPATTERN	Sets the background pattern.
SETPATTERN	Sets the turtle pattern.
SETPENCOLOR	Sets the pen color.

Data Commands

Access and manipulate data

.COMPARE	Compares its inputs, optionally caseless.
ASCII	Converts a character into its Unicode value.
BUTFIRST	Reports all but the first element of its input.
BUTLAST	Reports all but the last element of its input.
BUTMEMBER	Removes elements from a word or a list.
CHAR	Converts a number into a Unicode character.
DATE	Reports the date.
FIRST	Reports the first element of its input.
FLATTEN	Reports a flat version of its list input.
FPUT	Prepends an element to its input.
FROMMEMBER	Removes the first part of its input until a specified word or list is found.
ISEQ	Outputs a list of sequential integers.
ITEM	Returns a specific element of its input.
JOIN	Converts a list to a word.
LAST	Reports the last element of its input.
LIST	Concatenates its inputs to a list.
LOCAL	Declares local variables inside a procedure.
LOCALMAKE	Create and set a local name.
LOWERCASE	Converts its argument to lower case.
LPUT	Appends an element to its input.
MAKE	Assigns a value to a name.
MILLISECONDS	Outputs the number of milliseconds spent.
MIXEDCASE	Converts its argument to mixed case.
NAME	Assigns a value to a name.
PARSE	Parses a string and outputs a list.
PICK	Randomly picks an element.
QUOTE	Quotes its input.
RSEQ	Outputs a list of equally spaced rational numbers.
SENTENCE	Concatenates its inputs to a list, flattening lists.
SPLIT	Splits a word into a list using a separator.
SUBST	Substitutes text in a word or a list.
THING	Reports the value of a name.
TIME	Outputs the time.
UPPERCASE	Converts its argument to upper case.
VERINFO	Outputs Logo version information as a list.
VERSION	Outputs the Logo version.
WORD	Concatenates its inputs to a word.
XLIST	Concatenates its inputs to a parenthesized list.

Debugging

Track program execution.

BACKTRACE	Prints the list of nested procedure calls.
BPCLEAR	Deletes all breakpoints.
CONTINUE	Ends a pause.
PAUSE	Pauses a procedure.
STEP	Turns on stepping for the given elements.
STEPPED	Outputs a structured contents list of all stepped elements.
STEPPED?	Outputs TRUE if the element described by its input is stepped.
TRACE	Turns on tracing of the given elements.
TRACED	Outputs a structured contents list of all traced elements.
TRACED?	Outputs TRUE if the element described by its input is traced.
UNSTEP	Turns off stepping of the given elements.
UNTRACE	Turns off tracing of the given elements.

Program Flow

Control the program flow.

.MAYBEOUTPUT	Exits a procedure and outputs a value if present.
APPLY	Applies a parameter list to a procedure.
CASE	Outputs a value based on an input value.
CATCH	Catches runtime errors and THROWn data.
DO.UNTIL	Runs a list until a condition is true.
DO.WHILE	Runs a list until a condition is false.
ELSE	Starts the ELSE part of an IF command.
END	Ends a procedure definition.
ERROR	Outputs the last runtime error.
EVAL	Runs a list and collects all outputs.
FOR	Runs a list for a defined number of times.
FOREACH	Runs a list for each element of its first input.
FOREVER	Runs a list forever.
GO	Jumps to a label inside a procedure.
HALT	Stops one or all background programs.
IF	Runs instructions based on a condition.
IFFALSE	Runs a list if TEST was false.
IFTRUE	Runs a list if TEST was true.
IGNORE	Ignores the output of a procedure.
LABEL	Marks a target for the GO command.
LAUNCH	Launches a runlist or procedure for execution in the background.
LAUNCHED	Outputs a list of all active background engines.
MACROEXPAND	Outputs the expansion of a macro.
OUTPUT	Exits a procedure and outputs a value.
REPCOUNT	Reports the value of the REPEAT counter.
REPEAT	Runs a runlist repeatedly.
REPTOTAL	Reports the total number of REPEATs.
RUN	Runs a word or list.
STOP	Exits a procedure, or stops a program.
TEST	Test a condition; used with IFTRUE and IFFALSE.
TEXT	Outputs a procedure definition.
THEN	Starts the THEN part of an IF command.
THROW	Throws a Logo word or a runtime error.
TOPLEVEL	Returns to toplevel.
UNTIL	Runs a list until a condition is true.
WAIT	Waits for a number of milliseconds.
WHEN	Monitors a change to a Logo property or to a Logo event.
WHENEVER	Monitors changes to a Logo property or to a Logo event.
WHILE	Runs a list until a condition is false.

Built-in variables

A list of global variables.

:CASE	Makes Logo convert its input to upper case or not.
:CURRENT.GRAPHICS	Contains the current graphics window name.
:EPSILON	Contains the minimum value that two numbers may differ to still be considered to be equal.
:ERROR	Contains the type of the last runtime error.
:ERRORTEXT	Reports the text of the last caught runtime error or THROWn word.
:FENCE	Defines the way turtles bounce off the edges of the Graphics screen.
:LANGUAGE	Reports Logo’s UI language.
:LAYOUT	Gets or sets the panel layout.
:LOGO.ENV	Contains a property list of global program and system settings.
:LOGOENGINE	Contains the ID of the currently running Logo engine.
:MIDI.OUTPUT	Contains the name of the music synthesizer that Logo uses to play music.
:MIDI.OUTPUTS	Returns a list of synthesizer names that Logo supports for playing music.
:PICTURE.FORMAT	Contains the default file extension for graphics files.
:PRECISION	Sets the precision in which numbers are printed.
:PREFS	System-wide properties.
:PROMPT	Gets or sets the prompt for the Listener.
:STANDARD.INPUT	The number of the input stream.
:STANDARD.OUTPUT	The number of the output stream.
:TAB	Sets the tab stop position.
:TRACE	Controls the output of debugging information.

The Graphics canvas

BOUNCE	Lets the turtles bounce off the graphics bounds inside the Graphics panel.
BOUNDS	Reports the drawing bounds of the Graphics panel.
CLEAN	Erases the Graphics panel.
CLEARSCREEN	Erases the Graphics panel and homes the turtle.
DRAW	Clears the Graphics panel and resets all turtles.
FENCE	Fences all turtles inside the drawing bounds.
FREEZEPIC	Freezes the display of the Graphics panel.
LOADPIC	Loads a picture.
SAVEPIC	Saves the contents of the Graphics panel.
SETBOUNDS	Set the drawing bounds of the Graphics panel.
SNAP	Moves parts of the Graphics panel into a bitmap.
SNAPSIZE	Outputs the size of a bitmap.
STAMP	Draws a bitmap or turtle.
UNFREEZEPIC	Unfreezes the display of the graphics.
WINDOW	Removes the boundary for turtle movements.
WRAP	Lets the turtles wrap inside the Graphics panel.
GRID	Sets the characteristics of the graphics grid.
GRIDOFF	Hides the grid of the Graphics panel.
GRIDON	Displays the grid of the Graphics panel.

Infix Operators

=	Tests its inputs for equality.
>=	Tests if its left input is greater than or equal to its right input.
>	Tests if its left input is greater than its right input.
<=	Tests if its left input is less than or equal to its right input.
<	Tests if its left input is less than its right input.
!=	Tests its inputs for inequality.
-	Outputs the difference of two or more numbers.
^	Raises a number to the power of another number.
*	Calculates the product of its inputs.
/	Reports the quotient of its inputs.
%	Outputs the remainder of two numbers.
+	Reports the sum of its inputs.

Input and Output

Read and write data.

ALERT	Displays an alert box.
CLOSE	Closes a stream.
CONFIRM	Displays an alert box with Yes/No options and returns TRUE or FALSE.
CREATE	Creates a file.
CURDIR	Reports the current working directory.
DELETE	Deletes a file or a folder.
DIR	Lists the contents of current working directory.
EOF?	Outputs TRUE if the current stream is at EOF (end-of-file).
FILE?	Reports TRUE if a file or directory exists.
FORM	Formats a number.
OPEN	Opens a file and returns the channel number.
PATHNAME	Reports the full path name for a file name.
PRINT	Prints text with a line feed.
PRINTLINE	Prints a list of numbers as Unicode characters.
PRINTQUOTE	Prints its input and a newline.
PROGRESSBAR	Displays a progress bar.
READ	Reads one Logo word.
READCHAR	Read a character from the standard input stream.
READFILE	Reads and parses the contents of a file.
READLINE	Reads a line and outputs it as a list of numbers.
READLIST	Reads a line and outputs it as a list.
READPROMPT	Opens a dialog box and reads a line.
READQUOTE	Reads a line.
READWORD	Reads the next word of a line.
RENAME	Renames a file.
SETCURDIR	Changes the current working directory.
SHOW	Prints text with a line feed.
SUBDIR	Lists the contents of current working directory.
TYPE	Prints text.
WRITEFILE	Stores a Logo word or list into a file.

Listener Panel Commands

CLEARTEXT	Clears the Listener panel.
HTML	Creates and outputs a HTML sequence.
KEY	Reports the code of the last key that the user typed.
SETTEXTCOLOR	Sets the text color for Listener output.
SETTEXTFONT	Sets the Listener font.
TEXTCOLOR	Reports the text foreground and background colors.
TEXTFONT	Reports the font used for output.
WEBLINK	Creates and outputs a HTML web link.

Math Commands

Arithmetic computations.

ABS	Reports the absolute value of a number.
AND	Logical AND.
ARCCOS	Reports the arccosine.
ARCCOT	Reports the arccotangent.
ARCCSC	Reports the arccosecant.
ARCSEC	Reports the arcsecant.
ARCSIN	Reports the arcsine.
ARCTAN	Reports the arctangent.
ARCTAN2	Reports the polar angle heading of the motion vector (position change) deltaX deltaY.
ASHIFT	Shifts its input with sign extension.
LOGAND	Combines its inputs with a bitwise AND operation.
LOGNOT	Reports the bitwise logical complement of its input.
LOGOR	Combines its inputs with a boolean OR operation.
LOGXOR	Combines its inputs with a boolean XOR operation.
COS	Reports the cosine.
COT	Reports the cotangent.
CSC	Reports the cosecant.
DIFFERENCE	Outputs the difference of two or more numbers.
EXP	Calculates the natural base e raised to a power.
INT	Reports the integer part of a number.
LOG	Outputs the natural logarithm of its input.
LOG10	Outputs the logarithm of its input.
LSHIFT	Shifts its input without sign extension.
MINUS	Outputs the negative value of its input.
MODULO	Outputs the remainder of two numbers.
NOT	Negates its input.
OR	Performs a logical OR on its input.
PI	Reports the number Pi.
POWER	Raises a number to the power of another number.
PRODUCT	Calculates the product of its inputs.
QUOTIENT	Reports the quotient of its inputs.
RANDOM	Outputs a random number.
REMAINDER	Outputs the remainder of two numbers.
RERANDOM	Seed the random number generator.
ROUND	Rounds a number.
SEC	Reports the secant.
SIN	Reports the sine.
SQRT	Reports the square root.
SUM	Reports the sum of its inputs.
TAN	Reports the tangent.

Multimedia Commands

MIDI.RECORD	Records and saves music commands that PLAY plays.
PLAY	Plays sound files or notes.
PLAY.NOTES	Plays simple songs on a robot’s speaker.
PLAY.SOUND	Play a predefined sound on a robot’s speaker.
SAY	Makes Logo speak its input.
SELECT.VOICE	Opens a dialog where you can select a voice for the SAY command.

Mouse Commands

BUTTON?	Reports the state of the left mouse button.
MOUSE	Reports the position of the mouse cursor.
MOUSESHAPE	Reports the shape of the mouse cursor.
SETMOUSESHAPE	Sets the shape of the mouse cursor.

Objects

Create and manipulate objects.

.WHO	Reports a list of widgets listening to commands.
ALLTURTLES	A list of all turtles.
ASK	Makes widgets execute a list of commands.
CHECKTYPE	Checks an value for a type.
DECLARE	Creates a widget.
EACH	Applies a runlist to every widget in the TELL list.
EVERY	Outputs a list of widgets.
IS.A	Checks an widget for being of a specific type.
NEW	Creates a new Logo widget.
TELL	Defines a list of turtles (or other widgets) listening to commands.
TELLALL	Tells a range of turtle numbers.
TELLEVEN	Tells all turtles with even numbers.
TELLODD	Tells all turtles with odd numbers.
TYPEOF	Reports the type of a name.
WHO	Reports a list of turtles (or other widgets) listening to commands.

Queries

COUNT	Counts the number of items in its input.
DEFINED?	Checks whether a procedure is defined.
EMPTY?	Checks whether a name is empty.
LIST?	Checks for its input being a list.
MACRO?	Checks its input for being a macro.
MEMBER?	Checks if an object is part of another object.
NAME?	Checks whether its input is assigned a value.
NUMBER?	Checks its input for being a number.
PLIST?	Checks its input for containing a property list.
PRIMITIVE?	Checks its input for being a built-in procedure or macro.
PROCEDURE?	Checks its input for being a user-defined procedure.
WORD?	Checks its input for being a word.
EQUAL?	Tests its inputs for equality.
GREATEREQUAL?	Tests if its first input is greater than or equal to its second input.
GREATER?	Tests if its first input is greater than its second input.
LESSEQUAL?	Tests if its first input is less than or equal to its second input.
LESS?	Tests if its first input is less than its second input.
NOTEQUAL?	Tests its inputs for inequality.

Property lists

Add, retrieve, or remove properties.

CPROP	Calls a property as a procedure.
GLIST	Reports the property lists that contain a property with a given name.
GPROP	Retrieves a property.
PLIST	Reports the property list of a name.
PPROP	Stores a property.
PPROPS	Sets a list of properties.
REMPROP	Removes a property.

Robot Commands

BLUEBOT.BATTERY	Reports Blue-Bot’s battery level.
BLUEBOT.CLEAR	Clears all commands stored in Blue-Bot’s memory.
BLUEBOT.CLOSE	Disconnects the Blue-Bot from Logo.
BLUEBOT.GO	Executes commands stored in Blue-Bot’s memory.
BLUEBOT.RUN	Executes Blue-Bot commands.
BLUEBOT.WRITE	Downloads a procedure to Blue-Bot.
BLUEBOT?	Tests if the Blue-Bot is connected and ready to receive commands.
INOBOT.CLOSE	Closes the connection to an InO-Bot
INOBOT?	Tests if an InO-Bot is connected and ready to receive commands.
LED	Controls a robot’s LEDs.
MOTORS	Controls a robot’s motors.
SELECT.BLUETOOTH	Selects a Bluetooth device.
TUFFBOT.BATTERY	Reports Tuff-Bot’s battery level.
TUFFBOT.BUTTONS	Programs Tuff-Bot’s buttons.
TUFFBOT.CLEAR	Clears all commands stored in Tuff-Bot’s memory.
TUFFBOT.CLOSE	Disconnects the Tuff-Bot from Logo.
TUFFBOT.GO	Executes commands stored in Tuff-Bot’s memory.
TUFFBOT.OBSTACLE	Downloads an obstacle avoidance routine to Tuff-Bot.
TUFFBOT.RUN	Executes Tuff-Bot commands.
TUFFBOT.WRITE	Downloads a procedure to Tuff-Bot.
TUFFBOT?	Tests if the Tuff-Bot is connected and ready to receive commands.

Bitmaps and Turtles

ARC	Draws an arc.
BACK	Moves a turtle backwards.
CTURTLES	Arranges turtles in a circle.
DISTANCE	Reports the distance between the turtle and a location.
DOT	Draws a dot.
DOT?	Tests whether a pixel is present at the given location.
DOTCOLOR	Reports the color of a pixel.
EDSHAPE	Launches the shape editor.
FILL	Fills an area.
FONT	Reports the current font of the first active turtle.
FONTS	Reports a list of all loaded and available fonts.
FORWARD	Moves a turtle forward.
HEADING	Reports the heading of the first active turtle.
HIDETURTLE	Hides all active turtles.
HOME	Moves the turtle back to [0 0].
LEFT	Turns a turtle left.
LOADSHAPE	Loads a turtle shape from a file and sets the shape of all active turtles.
LOADSNAP	Loads a bitmap.
LTURTLES	Arranges turtles in a row.
OPACITY	Reports the opacity of the first active turtle.
ORIGIN	Reports the origin of a turtle’s coordinate system.
PANGLE	Reports the turtle’s angle as a polar angle.
PDIST	Reports the distance from the turtle to its home.
PEN	Reports the pen mode.
PENDOWN	Puts the pen down.
PENDOWN?	Checks whether the pen is down.
PENERASE	The pen draws with the background color.
PENREVERSE	The pen inverts all colors.
PENUP	The pen moves up.
PHEADING	Reports the turtle’s polar heading.
POS	Reports the coordinates of a turtle.
PPOS	Reports the turtle’s polar position.
PSETHEADING	Sets the polar heading of a turtle.
RIGHT	Turns a turtle right.
SAVESHAPE	Saves the shape of the first active turtle.
SAVESNAP	Saves a turtle shape.
SETFONT	Sets the turtle drawing font.
SETHEADING	Sets the heading of a turtle.
SETOPACITY	Sets the opacity of all active turtles.
SETORIGIN	Sets the coordinate system origin of the active turtles.
SETP	Sets the turtle’s polar position.
SETPEN	Sets the pen characteristics.
SETSHADOW	Sets the drop shadow for all active turtles.
SETSHAPE	Sets the shape of all active turtles.
SETSPEED	Sets the speed at which turtle commands are executed.
SETSTEPSIZE	Sets the step size of all active turtles and bitmaps.
SETTURTLENAME	Sets the name of a turtle.
SETVELOCITY	Controls the speed of an independently moving widget.
SETWIDTH	Sets the pen width.
SETX	Sets the X coordinate of a turtle.
SETXY	Sets the coordinates of a turtle.
SETY	Sets the Y coordinate of a turtle.
SHADOW	Reports the drop shadow for the first active turtle.
SHAPE	Outputs the name of the first active turtle’s shape.
SHOWN?	Reports whether a turtle is visible.
SHOWTURTLE	Makes a turtle visible.
SLOWTURTLE	Slows down the turtle to half speed.
SPEED	Reports the speed at which turtle commands are executed.
STAMPOVAL	Draws an oval.
STAMPRECT	Draws a rectangle.
STAMPRECTC	Draws a rectangle centered around the turtle position.
STEPSIZE	Outputs the step size of the first active turtle or bitmap.
TOWARDS	Reports the angle of a position compared to the turtle position.
TURTLENAME	Gets the name of the first active turtle.
TURTLENAMES	Outputs a list of all turtle names.
TURTLES	Reports the number of turtles.
TURTLESIZE	Reports the scaling factor of a turtle.
TURTLETEXT	Prints its input on the Graphics panel.
TURTLETEXTSIZE	Outputs the dimensions of a text drawn with the first listening turtle.
VELOCITY	Reports the speed of an independently moving widget.
WIDTH	Reports the pen width.
GETX	Reports the X coordinate of a turtle.
GETY	Reports the Y coordinate of a turtle.
SETTURTLES	Creates a range of turtles.
LOCKSHAPE	Prevents a bitmap from turning.
SETTURTLESIZE	Sets the scaling factor of a bitmap.
UNLOCKSHAPE	Lets a bitmap rotate according to the turtle’s heading.

The Workspace

.DEFMACRO	Defines a macro.
.MACRO	Defines a macro.
ALIAS	Defines alias names.
BURIED	Outputs a structured contents list of all buried elements.
BURIED?	Outputs TRUE if the element described by its input is buried.
BURIEDNAMES	Outputs a list of all buried names.
BURIEDPROCS	Outputs a list of all buried procedures.
BURIEDPROPS	Outputs a list of all buried property lists.
BURY	Makes names and procedures invisible.
BURYALL	Makes all names and procedures invisible.
BURYNAME	Makes one or more names invisible.
BURYNAMES	Makes all names invisible.
BURYPROC	Makes one or more procedures invisible.
BURYPROCS	Makes all procedures invisible.
BURYPROP	Makes one or more property lists invisible.
BURYPROPS	Makes all property lists invisible.
CONTENTS	Outputs a complete structured contents list.
COPYDEF	Copies a procedure definition.
DEFINE	Defines a procedure.
EDALL	Edits the entire Logo workspace.
EDIT	Edits parts or all of the Logo workspace.
EDN	Edits one or more Logo names.
EDNS	Edits all Logo names.
EDPL	Edits one or more Logo property lists.
EDPLIST	Edits the properties of a property list, a widget, or a panel.
EDPLS	Edits all Logo properties.
EDPS	Edits all user-defined, unburied procedures.
ERALL	Erases the entire Logo workspace.
ERASE	Erases Logo elements.
ERN	Erase one or more Logo names.
ERNS	Erases all Logo names.
ERPL	Erases one or more Logo property lists.
ERPLS	Erases all Logo properties.
ERPS	Erases all procedures.
HELP	Displays help for a command.
LOAD	Loads a file into Logo.
NAMELIST	Outputs a structured contents list with names.
NAMES	Outputs a structured contents list with all names.
PHELP	Displays help for a property.
PLISTS	Outputs a structured contents list with all properties.
PLLIST	Outputs a structured contents list with properties.
POALL	Prints the entire Logo workspace.
PON	Prints a Logo name.
PONS	Prints all Logo names.
POPL	Prints one or more Logo property lists.
POPLS	Prints all Logo properties.
POPS	Prints all Logo procedures.
POT	Prints the title line of one or more user-defined procedures.
POTS	Prints the title line of all user-defined procedures.
PRIMITIVES	Outputs a structured contents list with all primitives.
PRINTOUT	Prints procedures, names, or properties.
PROCEDURES	Outputs a list with all user procedures.
PROCLIST	Outputs a structured contents list with procedures.
QUIT	Ends Logo.
RESTART	Erases everything and restarts Logo.
SAVE	Saves the workspace.
BS	Arranges the Blocks, Graphics, Listener, and Editor panels.
BSV	Arranges the Blocks, Graphics, Lister and the Editor panels.
FS	Switches to the Full Screen perspective
ES	Makes the Graphics, Listener, and Editor panels visible.
ESV	Makes the Graphics panel, the Lister panel and the Editor panel visible.
SS	Displays the Graphics panel above the Listener panel.
SSV	Displays the Graphics panel to the left of the Listener panel.
TS	Minimizes the Graphics panel and maximizes the Listener panel.
TO	Defines a procedure.
UNBURY	Makes names and procedures visible.
UNBURYALL	Makes all names and procedures visible.
UNBURYNAME	Makes one or more names visible.
UNBURYNAMES	Makes all names visible.
UNBURYPROC	Makes one or more procedures visible.
UNBURYPROCS	Makes all procedures visible.
UNBURYPROP	Makes one or more property lists visible.
UNBURYPROPS	Makes all property lists visible.