LOGO Primitives

Command

Short Form

Example

Description

ALLTURTLES

ALLTURTLES outputs a list of the numbers of every turtle that currently defined in Logo. ALLTURTLES is equivalent to the command EVERY "TURTLE.

TURTLES

The TURTLES command reports the total number of available turtles.

WHO

WHO reports the list of currently active turtles as set by the TELL command. Turtle numbers are reported, even if the turtles have been assigned names.

.WHO

.WHO reports a list of currently active turtles as set by the TELL command. Turtle numbers are reported, even if the turtles have been assigned names. The list reported by TURTLENAMES can help you match turtle names and numbers. .WHO always outputs a list, unlike WHO, even if there is only one Logo object listening.

TURTLENAME

TNAME

TURTLENAME reports the name of the first active turtle. The turtle has a default name of the form TURTLE.n, where n is the turtle number.

TURTLENAMES

TNAMES

TURTLENAMES reports a list of the names of all available turtles. A turtle with no name is represented by the empty list.

SETTURTLENAME number word

SETTNAME number word

SETTURTLENAME 0 "BOAT

SETTURTLENAME takes a turtle number and a word as input and assigns that name to the given turtle. After naming turtles, you can refer to them by their numbers or names.

ASK number list 

ASK 1 [ST FD 50]

ASK causes the turtle(s) named in its first argument to execute the commands in its second argument. ASK makes it possible to send commands to a turtle that is not currently active without making it one of the active turtles.

TELL number 
TELL name 
TELL list 

TELL 0 FD 50

TELL “ARROW

TELL [0 1 2 3 4 5]

TELL activates the objects that respond to turtle commands. Objects may either be turtles, bitmaps or controls. A single number as an argument to TELL activates that single turtle. A list of numbers or names activates all the turtles, bitmaps or controls named in the list.

TELLALL number number

TELLALL 0 15 RT 90 FD 50

TELLALL activates a range of turtles to respond to turtle commands. TELLALL takes two numbers as arguments. The first number is the number of the first turtle in the range to be activated. The second number is the last turtle in the range to be activated. Use TELL to activate a single turtle or a list of turtles.

TELLEVEN

TELLEVEN SETH 90

TELLEVEN activates all the even numbered available turtles.

TELLODD

TELLODD SETH 270

TELLODD activates all the odd numbered available turtles.

EACH list

EACH [SETPC RANDOM 14]

EACH causes each of the currently active turtles to execute the commands contained in its argument sequentially. This allows each of several turtles to be given a variable input or to be addressed by WHO or its current number.

SETTURTLES number

SETTURTLES 4

SETTURTLES erases all of your turtles and then defines the total number of new turtles available. Their numbers range from 0 to the input of SETTURTLES minus 1. For example, SETTURTLES 16 will create the turtles [0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15]. By default, Logo starts with 16 turtles defined and turtle 0 activated.

SETTURTLES creates turtles with the following characteristics:

Position	Home (0,0)
Turtle size	1
Heading	0
Line width	1
Color	0 (black)
Turtle speed	0
Visibility	hidden
Pattern	solid
Pen state	pen down
Origin:	[0 0]
Font:	Default system font, 10 points
Extent:	[0 0]

NEW “TURTLE

NEW “TURTLE

Allows you to create an additional turtle if you didn’t create enough turtles using the SETTURTLES command.

DECLARE “TURTLE “SKIER

DECLARE “TURTLE “SKIER

Allows you to create an additional turtle if you didn’t create enough turtles using the SETTURTLES command while giving the turtle a name.