control

@

control

primitivename

none

@ allows you to run the built-in primitive of the given primitivename, when there is a user-defined procedure with that name typically overriding it. See runprimitive

@forward 20

after

control

time-in-milliseconds (number) | requests (list)

none

After the specified amount of time the list of requests is performed by the current turtle in a new thread.

after 1000 [print [One second has passed.]]

age

control

none

Returns the age of the current turtle in milliseconds. Reset it with resetage

show age
show snappy:age

Creates new workers for each specified turtle in the word or list, and causes them to execute the instructions in the following list. Existing workers are not interrupted and as such they may conflict!

ask “myrtle [fd 20]

ask [myrtle snappy] [fd 20]

break

control

none

‘Breaks’ or exits from the current loop, for example repeat or foreach, and continues execution.

repeat 10 [print repcount if repcount = 5 [break]] print "Broken!
1
2
3
4
5
Broken!

calm

control

turtle (word)

turtles (list)

none

Stops all workers running in the specified turtle(s). See halt

calm "snappy
calm [snappy myrtle]

co

control

none

Continues execution if that execution was halted by the pause primitive. See pause.

co

control

control

turtle (word) | primitives (list)

none

Executes the specified primitives using the specified turtle in the thread that calls the control primitive. Same as executing turtle:run [do these things], but easier to automate, for example: foreach “turtle everyone [control :turtle [fd 10]]

control "snappy [orbitleft 20]

dawdle

control

none

Waits until all of the turtle’s workers except for its ‘main’ one and / or hatchlings finish executing.

newworker [repeat 100 [wait 1]] dawdle print |Done waiting.|

die

control

none

die halts the thread that calls it. Useful for terminating execution arbitrarily, although it should be done more gracefully, where possible.

die

eraseturtle

control

name (word)

none

Erases the specified turtle

erase "fred

escape

control

none

Allows the user to use the escape key to halt all execution. See noescape

escape

everyone

control

none

list

Returns a list of all turtles except Snappy, which is a camera-only turtle. Useful to use with foreach to iterate through a series of instructions with each turtle.

show everyone
["myrtle]

finish

control

none

Halts all threads in all turtles. Stops the world. Can be invoked by pressing the escape key, unless noescape has been invoked.

finish

halt

control

worker (number) or workers (list)

none

Halts the specified worker or workers. The worker(s) must be owned by the turtle calling halt.

halt 7
halt [7 9]

interrupt

control

turtle (word) | instructions (list)

none

Stops all workers executing in the specified turtle, and creates another to preform the specified instructions. The interrupted execution does not resume after the instructions have been executed. Similar to arrest “turtle ask “turtle [instructions]

interrupt "snappy [orbitleft 90]

listworkers

control

none

Displays a list of operating workers.

listworkers

marco

control

turtle (word)

none

Marco causes the calling turtle to wait until the specified turtle calls polo. This allows for some simple synchronisation between turtles. See marcop, marcos, polo

marco "snappy

marcos

control

none

list

Returns a list of all the turtles that have called marco on the calling turtle. See marco

show marcos

myworker

control

none

id (number)

Returns the worker ID of the worker that calls it. See myworkers

show myworker

myworkers

control

none

list

Returns a list of the IDs of the workers belonging to the calling turtle or its hatchlings. Hatchlings do not own workers, only ‘root’ turtles. myworkers doesn’t return any results if called by a hatchling. See newworker, workers

show myworkers

newworker

control

list

none

creates a new ‘worker’ and executes the contents of the list of primitives or procedures provided to it.

newworker [forever [rt random 180 fd random 100]]

newworkerid

control

list

number

newworkerid creates a new worker the same as newworker, but acts as a function and returns the thread ID of the new worker.

show newworkerid [forever [rt random 180 fd random 100]]

noescape

control

none

Disables the ability of the escape key to halt all execution. See escape

noescape

nosync

control

none

Cancels a current sync. See sync

nosync

pacify

control

none

Calms (stops) all turtles except for the turtle who calls pacify. See calm

pacify

polo

control

turtle (word)

none

Calls polo on the specified turtle. See marco, marcop, marcos

polo "myrtle

request

control

turtle [list of instructions]

none

Performs the provided series of instructions once the specified turtle has no other workers executing. See interrupt for a more abrupt way of doing this

request "myrtle [sphere 50]

resetage

control

none

Resets the current turtle’s age. See age

resetage

resume

control

worker (number) or workers (list)

none

Resumes execution of the specified worker(s). See suspend, newworker

resume 7

run

control

list

none

Executes the provided list of primitives. This allows you to use various word and list functions to dynamically generate turtleCode into a list which can then be executed.

make "square [repeat 4 [forward 20 right 90]]
run :square

runprimitive

control

list

none

Executes the provided list of primitives and procedures with primitives given precedence over procedures (the opposite of normal execution). For example, if you have a procedure named forward, it would ordinarily override attempts to execute the forward primitive. However, if you pass forward to runprimitive, runprimitive will execute the forward primitive in preference to your procedure. You can also accomplish the same effect as runprimitive by prefacing a primitive with @. See examples

runprimitive [forward 20]
@forward 20

sleep

control

milliseconds

none

Causes execution to pause for the specified number of milliseconds. Useful when working with time to calculate delays. Alternative to wait.

sleep 1000

solo

control

none

Stops all threads running in the calling turtle except the thread executing solo, if that thread belongs to that turtle.

solo

stop

control

none

Stops execution inside the current procedure and returns to the level above, if it exists, or stops execution of the thread entirely.

stop

suspend

control

worker (number) or workers (list)

none

Suspends execution of the specified worker(s). See resume, newworker

suspend 7

sync

control

none

Causes turtle to wait until all other turtles in its ‘family’ (siblings, parents, hatchlings) also call sync, or if any of them call a nosync. Commonly used to synchronise multithreaded hordes of game objects, such as enemies. See syncp, nosync, marco

ht repeat 20 [hatch [forever [randomvectors fd 10 sync]]] forever [until syncp [wait 60] sync]

wait

control

60ths-of-a-second (number)

none

Pauses execution for the amount of time specified in 60ths of a second. wait 60 pauses for one second.

wait 60

workerp

control

id-number

boolean

Returns true if worker with id-number is running.

print workerp 123

workers

control

none

list

Returns a list of running workers.

show workers

Control

control