Terrapin Resources

Commands Overview by Group

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

Accessors

Access data.

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.
FIRST Reports the first element of its input.
FLATTEN Reports a flat version of its list input.
FROMMEMBER Removes the first part of its input until a pattern is found.
ITEM Returns a specific element of its input.
JOIN Converts a list to a word.
LAST Reports the last element of its input.
LOWERCASE Converts its argument to lower case.
MIXEDCASE Converts its argument to mixed case.
PICK Randomly picks an element.
SPLIT Splits a word into a list using a separator.
UPPERCASE Converts its argument to upper case.

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.

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 Sets the structure of an array.

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.

Logo Colors

The color commands assign colors to the background of the Graphics canvas, or the turtle pen.

ALPHA Reports the first active turtle’s alpha value.
BACKGROUND Reports the background color.
COLOR Reports the RGB color value for a color name or color index.
COLORINDEX Coerces a color value to a basic Logo color number.
BGPATTERN Reports the background pattern.
COLOR Reports the color for a name or value if possible.
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 alpha value for colors.
SETBG Sets the background color.
SETBGPATTERN Sets the background pattern.
SETPATTERN Sets the turtle pattern.
SETPC Sets the pen color.

Contents lists

Contents list commands manipulate several items at once using structured contents lists.

CONTENTS Outputs a complete structured contents list.
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.
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.
EDPS Edits all user-defined, unburied procedures.
EDPLS Edits all Logo properties.
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.
NAMELIST Outputs a structured contents list with names.
NAMES Outputs a structured contents list with all names.
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.
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.

Data Commands

Access and manipulate data

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.

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.
TRACE Turns on tracing of the given elements.
TRACED Outputs a structured contents list of all traced elements.
UNSTEP Turns off stepping of the given elements.
UNTRACE Turns off tracing of the given elements.

Turtle Drawing

Move turtles around, and make them draw.

ARC Draws an arc.
BACK Moves a turtle backwards.
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.
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.
GETX Reports the X coordinate of a turtle.
GETXY Reports the coordinates of a turtle.
GETY Reports the Y coordinate of a turtle.
HEADING Reports the heading of a turtle.
HIDETURTLE Hides a turtle.
HOME Moves the turtle back to [0 0].
LEFT Turns a turtle left.
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.
PPOS Reports the turtle’s polar position.
PSETHEADING Sets the polar heading of a turtle.
RIGHT Turns a turtle right.
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.
SETSPEED Sets the speed at which turtle commands are executed.
SETSTEPSIZE Sets the step size of all active turtles and bitmaps.
SETTURTLESIZE Sets the scaling factor of a widget.
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.
SHOWN? Reports whether a turtle is visible.
SHOWTURTLE Makes a turtle visible.
SLOWTURTLE Slows down the turtle to half speed.
SPEED Reports the speed in which turtle commands are executed.
STAMPOVAL Draws an oval.
STAMPRECT Draws a rectangle.
STEPSIZE Outputs the step size of the first active turtle or bitmap.
TOWARDS Reports the angle of a position compared to the turtle position.
TURTLESIZE Reports the scaling factor of a turtle.
TURTLETEXT Prints its input on the Graphics canvas.
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.

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.

Program Flow

Control the program flow.

APPLY Applies a parameter list to a procedure.
CASE Outputs a value based on an input value.
CATCH Catches runtime errors and THROWn data.
COPYDEF Copies a procedure definition.
DEFINE Defines a procedure.
.DEFMACRO Defines a macro.
DO.UNTIL Runs a list until a condition is true.
DO.WHILE Runs a list until a condition is false.
ELSE Starts the ELSE branch 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.
LOCAL Declares local variables inside a procedure.
.MACRO Defines a macro.
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 branch of an IF command.
THROW Throws a Logo word or a runtime error.
TO Defines a procedure.
TOPLEVEL Returns to toplevel.
UNTIL Runs a list until a condition is true.
WAIT Waits for a number of milliseconds.
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 beconsidered 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.

The Graphics canvas

The Graphics canvas is the drawing surface for the turtles.

BOUNDS Reports the drawing bounds of the Graphics canvas.
BOUNCE Lets the turtles bounce off the graphics bounds inside the Graphics canvas.
BUTTON? Reports the state of the left mouse button.
CLEAN Erases the graphics canvas.
CLEARSCREEN Erases the graphics panel and homes the turtle.
DRAW Clears the current graphics canvas and resets all attached turtles.
FENCE Fences all turtles inside the drawing bounds.
FREEZEPIC Freezes the current graphics display.
GRID Sets the characteristics of the graphics grid.
GRIDOFF Hides the grid of the Graphics panel.
GRIDON Displays the grid of the Graphics panel.
LOADPIC Loads a picture.
MOUSE Reports the position of the mouse cursor.
MOUSESHAPE Reports the shape of the mouse cursor.
REDO Redoes the last drawing command after an UNDO command.
SAVEPIC Saves the contents of the Graphics panel.
SETBOUNDS Set the drawing bounds of the current Graphics canvas.
SETMOUSESHAPE Sets the shape of the mouse cursor.
UNDO Undoes the last drawing command.
UNFREEZEPIC Unfreezes the current graphics display.
WINDOW Removes the boundary for turtle movements.
WRAP Lets the turtles wrap inside the canvas.

Grids

A Logo grid is a special control that lets you arrange widgets in a grid.

FILLGRID Sets the text values of a grid.
GGET Outputs the name of a widget stored in a grid cell.
GGETTEXT Outputs the text of a grid cell.
GPPROP Alters a property of a grid, a row, a column, or a cell.
GRIDDIMS Reports the size of a grid.
GSET Stores a widget into a grid cell.
GSETTEXT Stores a text into a grid cell.
LISTGRID Reports the values of a grid as a list.
SETGRIDDIMS Sets the size of a grid.

Hit Tests

Commands to determine if two widgets collide.

HIT? Tests the first active widget against widgets listed on the hit list.
HITTABLE Reports the contents of the hit list.
PLACE Attempts to place the active widgets at the suggested location.
SETHITTABLE Sets the contents of the hit list.

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.
[^](/logo6/commands/infix#infix-11) 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.
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.
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.

Input and Output

Read and write data.

ALERT Displays an alert box.
CLOSE Closes a stream.
CREATE Creates a file.
CREATE.DIR Creates a folder.
CURDIR Reports the current working directory.
DELETE Deletes a file or a folder.
DIRECTORY Lists the contents of current working directory.
EOF? Outputs TRUE if the current stream is at EOF.
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 disk file.
SELECT.FILE Displays a dialog to select a file.
SELECT.FOLDER Displays a dialog to select a folder.
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.

Listener Panel Commands

Commands specific to the Listener.

HTML Creates and outputs a HTML sequence.
KEY Reports the code of the last key that the user typed.
SETTEXTCOLOR Sets the text color in the Listener panel.
SETTEXTFONT Sets the font for PRINT, TYPE and other output commands.
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.

Math

Math operators and functions.

ABS Reports the absolute value of a number.
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.
COS Reports the cosine.
COT Reports the cotangent.
CSC Reports the cosecant.
EXPN 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.
LOGAND Combines its inputs with a boolean 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.
LSH Shifts its input with sign extension.
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.
PI Reports the number Pi.
RADARCTAN Reports the arc tangent of an angle expressed in radians.
RADCOS Reports the cosine of an angle expressed in radians.
RADSIN Reports the sine of an angle expressed in radians.
RANDOM Outputs a random number.
RERANDOM Seed the random number generator.
ROUND Rounds a number.
SEC Reports the secant.
SIN Reports the sine.
SQRT Reports the square root.
TAN Reports the tangent.
POWER Raises a number to the power of another number.
DIFFERENCE Outputs the difference of two or more numbers.
SUM Reports the sum of its inputs.
PRODUCT Calculates the product of its inputs.
QUOTIENT Reports the quotient of its inputs.
REMAINDER Outputs the remainder of two numbers.
.EQ Tests its inputs for equality.
.NE Tests its inputs for inequality.
.LT Tests if its first input is less than its second input.
GREATER? Tests if its first input is greater than its second input.
.GE Tests if its first input is greater than or equal to its second input.
.LE Tests if its first input is less than or equal to its second input.
AND Logical AND.
OR Performs a logical OR on its input.

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.

Manipulate the Terrapin Logo menu.

APPENDMENU Appends a new menu.
APPENDMENUITEM Appends a new menu item.
COMMAND Invoke a menu command by its ID.
DELETEMENU Deletes a menu.
DELETEMENUITEM Deletes a menu item.
FINDMENUID Finds the ID of a menu item.

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.

Multimedia Commands

Play notes, MIDI and other audio fiules.

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.

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.

Objects

Create and manipulate widgets and other objects.

.WHO Reports a list of objects listening to commands.
ASK Makes objects execute a list of commands.
CHECKTYPE Checks an value for a type.
DECLARE Creates an object.
EACH Applies a runlist to every object in the TELL list.
EVERY Outputs a list of objects.
IS.A Checks an object for being of a specific type.
NEW Creates a new Logo object.
TELL Defines a list of objects 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 objects 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.

Property lists

Add, retrieve, call, 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 Stores a list of properties.
REMPROP Removes a property.

Putting things together

put together Logo words or lists, or access elements of Logo words or lists.

FPUT Prepends an element to its input.
ISEQ Outputs a list of sequential integers.
LIST Concatenates its inputs to a list.
LPUT Appends an element to its input.
PARSE Parses a string and outputs a list.
RSEQ Outputs a list of equally spaced rational numbers.
SENTENCE Concatenates its inputs to a list, flattening lists.
SUBST Substitutes text in a word or a list.
WORD Concatenates its inputs to a word.
XLIST Concatenates its inputs to a parenthesized list.

Queries

Test data or data contents.

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.

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.

Robot Commands

Talk to floor robots via Bluetooth.

BLUEBOT? Tests if the Blue-Bot is connected and ready to receive 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.
LED Controls a robot’s LEDs.
MOTORS Controls a robot’s motors.
SELECT.BLUETOOTH Selects a Bluetooth device.
TUFFBOT? Tests if the Tuff-Bot is connected and ready to receive commands.
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 Defines Tuff-Bot’s obstacle-avoidance subroutine.
TUFFBOT.RUN Executes Tuff-Bot commands.
TUFFBOT.WRITE Downloads a procedure to Tuff-Bot.

Turtle Shapes

Load, change, and lock turtle images.

EDSHAPE Launches the shape editor.
LOADSHAPE Loads a turtle shape from a data space and sets the shape of all active turtles.
LOADSNAP Loads a bitmap.
LOCKSHAPE Prevents a bitmap from turning.
SAVESHAPE Saves the shape of the first active turtle.
SAVESNAP Saves a turtle shape.
SETSHAPE Sets the shape of all active turtles.
SHAPE Outputs the name of the first active turtle’s shape.
SNAP Moves parts of the Graphics panel into a bitmap.
SNAPSIZE Outputs the size of a bitmap.
STAMP Draws a bitmap or turtle.
UNLOCKSHAPE Lets a bitmap rotate according to the turtle’s heading.

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.

Creating Turtles

Create and assign turtles.

ALLTURTLES A list of all turtles.
CTURTLES Arranges turtles in a circle.
LTURTLES Arranges turtles in a row.
SETTURTLES Creates a range of turtles.
SETTURTLENAME Sets the name of a turtle.
TURTLENAME Gets the name of the first active turtle.
TURTLENAMES Outputs a list of all turtle names.
TURTLES Reports the number of turtles.

Built-in variables

Global built-in variables reflect the state of Logo.

:CASE Controls the conversion of quoted symbols to upper case.
:CURRENT.GRAPHICS Contains the current graphics window name.
:DEFAULT.LAYOUT Reports the default Logo panel layout
: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.
:INITIAL.LAYOUT Reports or sets the initial Logo panel layout
:LANGUAGE Reports Logo’s UI language.
:LAYOUT Gets or sets the panel layout.
:LOGOENGINE Contains the ID of the currently running Logo engine.
:LOGO.ENV Contains a property list of global program and system settings.
: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 Listene.
: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.
:USERNAME Reports the user name for local storage.

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.

The Workspace

All commands related to the workspace.

ALIAS Defines alias names.
BYE Ends Logo.
CHAR Converts a number into a Unicode character.
CLEARTEXT Clears the Listener panel.
DATE Reports the date.
FULLSCREEN Switches to the Full Screen perspective
HELP Displays help for a command.
LMAKE Create and set a local name.
LOAD Loads a file into Logo.
MAKE Assigns a value to a name.
MILLISECONDS Outputs the number of milliseconds spent.
NAME Assigns a value to a name.
PHELP Displays help for a property.
QUOTE Quotes its input.
RESTART Erases everything and restarts Logo.
SAVE Saves the workspace to disk.
SPLITSCREEN Makes both the Listener panel and the Graphics canvas visible.
TEXTSCREEN Minimizes the Graphics canvas and maximizes the Listener panel.
THING Reports the value of a name.
TIME Outputs the time.
UNICODE Converts a character into its Unicode value.
VERINFO Outputs Logo version information as a list.
VERSION Outputs the Logo version.
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.