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Turtle Motion
right X , rt X
Rotate the turtle right x degrees
Example:
right 90
Explained in lesson:
setx NUM_x
Move turtle to the specified X location
Example:
setx 100
Explained in lesson:
sety NUM_y
Move turtle to the specified Y location
Example:
sety 200
Explained in lesson:
setxy NUM_X NUM_Y , set pos [ NUM_X NUM_Y ]
Move turtle to the specified location
Example:
setxy 100 100
Explained in lesson:
setheading , seth
Rotate the turtle to the specified heading
Example:
sh 145
Explained in lesson:
arc ANGLE RADIUS
Will create an arc distance RADIUS covering ANGLE angle
Example:
ARC 360 5
Explained in lesson:
ellipse WIDTH HEIGHT
Will create an ellipse with Width and height
Example:
ellipse 80 90
Turtle Motion Queries
pos
Outputs the current turtle position as [ x y ], x or y respectively
Example:
pos
Explained in lesson:
xcor
Outputs the current turtle position as [ x y ], x or y respectively
Example:
xcor
Explained in lesson:
ycor
Outputs the current turtle position as [ x y ], x or y respectively
Example:
ycor
Explained in lesson:
towards
Outputs the heading towards the specified [ x y ] coordinates
Example:
towards
Explained in lesson:
Turtle and Window Control
showturtle , st
Show the turtle
Example:
ht wait st
Explained in lesson:
hideturtle , ht
Hide the turtle
Example:
hideturtle
Explained in lesson:
clearscreen , cs
Will clear the screen and return the turtle home
Example:
cs
Explained in lesson:
fill
Does a paint bucket flood fill at the turtle's position
Example:
cs repeat 4 [ fd 50 rt 90 ] pu setxy 50 50 pd fill
Explained in lesson:
filled fillcolor [ statements ... ]
Execute statements without drawing but keeping track of turtle movements. When complete, fill the region traced by the turtle with fillcolor and outline the region with the current pen style
Example:
filled "blue [repeat 4 [fd 100 rt 90]]
Explained in lesson:
label expr
Draw a word (same logic as print) on the graphics display at the turtle location
Example:
label "logo ht
Explained in lesson:
setlabelheight expr
Set the height for text drawn by label, in pixels
Example:
setlabelheight 100 label "Logo ht
Explained in lesson:
wrap
If the turtle moves off the edge of the screen it will continue on the other side
Example:
cs wrap fd 800
Explained in lesson:
window
The turtle can move past the edges of the screen, unbounded.
Example:
cs window fd 600 rt 90 fd 100 rt 90 fd 70
Explained in lesson:
fence
If the turtle attempts to move past the edge of the screen it will stop.
Example:
cs fence fd 600 rt 90 fd 100 rt 90 fd 70
Explained in lesson:
Turtle and Window Queries
shownp , shown?
Outputs 1 if the turtle is shown, 0 if the turtle is hidden
Example:
show shown?
Explained in lesson:
labelsize
Outputs the height of text drawn by label, in pixels
Example:
show labelsize
Explained in lesson:
Pen and Background Control
penup , pu
Turtle stops leaving a trail
Example:
penup
Explained in lesson:
pendown , pd
The turtle will leave a trail
Example:
pendown
Explained in lesson:
setcolor X , setpencolor X
| 0: black | 1: blue | 2: lime |
| 3: cyan | 4: red | 5: magenta |
| 6: yellow | 7: white | 8: brown |
| 9: tan | 10: green | 11: aquamarine |
| 12: salmon | 13: purple | 14: orange |
| 15: gray |
Example:
setcolor 1
Explained in lesson:
setcolor [r,g,b] , setpencolor [r,g,b]
Will set the turtle color accroding to the amount of red , green and blue
Example:
setcolor [50 100 50]
setwidth X , setpensize X
Will set the pen width to X
Example:
setwidth 4 fd 50
Explained in lesson:
changeshape X or STR , csh X or STR
Will change the turtle to another shape accordin to the following 0 = "turtle", 1 = "cat", 2 = "fish", 3 = "dog", 4 = "horse", 5 = "tiger", 6 = "crab", 7 = "snail"
Example:
csh 1 or csh "dog
Explained in lesson:
Pen Queries
pendownp , pendown?
Outputs 1 if the pen is down, 0 otherwise
Example:
show pendown?
Explained in lesson:
pencolor , pc
Outputs the current pen color. This will be a CSS color string, not necessarily the value passed in.
Example:
show pencolor
Explained in lesson:
pensize
Outputs a two element list with the pen width and height (usually the same).
Example:
show pensize
Explained in lesson:
Procedure Definition
to PROCNAME inputs ... statements ... end
Define a new named procedure with optional inputs
Example:
to TURTLE repeat 4 [ fd 50 rt 90] end
Explained in lesson:
define PROCNAME inputs ... statements ... end
Define a new named procedure with optional inputs
Example:
define "star [[n][repeat 5 [fd :n rt 144]]]
def PROCNAME
Outputs the definition of a named procedure as a string
Example:
show def "star
Variable Definition
make varname expr
Update a variable or define a new global variable. The variable name must be quoted
Example:
make "foo 5
Explained in lesson:
name expr varname
Like make but with the inputs reversed
Example:
name 5 "myvar
Explained in lesson:
localmake varname expr
Define a variable in the local scope (shortcut for local then make
Example:
localmake "myvar 5
Explained in lesson:
: VARNAME , thing VARNAME
Outputs the value of variable. :foo is a shortcut for thing "foo
Example:
show thing "myvar
Explained in lesson:
Control Structures
repeat X [ statements ... ]
Repeat statements X times
Example:
repeat 4 [ fd 50 rt 90]
Explained in lesson:
for controllist [ statements ...]
Typical for loop. The controllist specifies three or four members: the local varname, start value, limit value, and optional step size
Example:
for [i 1 10 1] [print :i]
Explained in lesson:
repcount
Outputs the current iteration number of the current repeat or forever
Example:
repeat 4 [ repcount ]
if expr [statement]
Execute statment if expressoin is true
Example:
if 2>1 [print "hello]
ifelse expr [statementTrue] [statementFalse]
Execute StatementTrue if tru else execute statementFalse
Example:
ifelse 0>1 [print "true] [print "false]
test expr
Test the specified expression save the result in the local scope for the subsequent use by iftrue iffalse
Example:
test 3>4 iftrue [print "true] ifflase [print "false]
iftrue [statements]
Example:
test 3>4 iftrue [print "true] ifflase [print "false]
ifflase [statements]]
Example:
test 3>4 iftrue [print "true] ifflase [print "false]
wait X
Will cause the turtle to wait X ( 60ths of seconds ) time before executing the command
Example:
repeat 4 [ wait 10 fd 50]
Explained in lesson:
bye
Ternimante the program
Example:
bye
dotimes [varname times] [ statements ...]
Run the statements the specified number of times. The variable varname is set to the current iteration number.
Example:
dotimes [ i 5 ] [ show :i * :i ]
do.while [ statements ...] expr
Runs the specified statements at least once, and repeats while the expression is non-zero (true).
Example:
do.while [ make "a random 10 show :a ] :a < 8
while [expr] [ statements ...]
Runs the specified statements only while the expression remains non-zero (true).
Example:
while (random 2) = 0 [ show "zero ] show "one
do.until [ statements ...] [expr]
Runs the specified statements at least once, and repeats while the expression is zero (false).
Example:
do.until [ make "a random 10 show :a ] :a < 8
until [expr] [ statements ...]
Runs the specified statements only while the expression remains zero (false).
Example:
until (random 2) = 0 [ show "one ] show "zero
Lists
list thing1 thing2 ...
Create a new list from the inputs
Example:
make "mylist (list "turtle "academy)
Explained in lesson:
first listname
Outputs the first item from the list
Example:
print first :mylist
Explained in lesson:
butfirst listname
Outputs all the items of listname except for the first item
Example:
print butfirst :mylist
Explained in lesson:
last listname
Outputs the last item from the list
Example:
print last :mylist
Explained in lesson:
butlast listname
Outputs all the items of listname except for the last item
Example:
print butlast :mylist
Explained in lesson:
item index listname
Outputs the indexlist item of the list or array
Example:
print item 1 :mylist
Explained in lesson:
pick index listname
Outputs one item from a list, at random
Example:
print pick :mylist
Explained in lesson:
Math
minus X Y
return the distance between x and y x-y
Example:
print minus 8 2
random X
Will choose a random number between 0 - (X-1)'
Example:
cs print sum random 10 3
Explained in lesson:
modulo expr expr
Outputs the remainder (modulus). For remainder and % the result has the same sign as the first input; for modulo the result has the same sign as a the second input.
Example:
cs print modulo 10 3
power expr expr
3 power 4 = 81
Example:
show power 3 4
Receivers
readword
Prompt the user for a line of input. The result (including spaces) is the single word output.
Example:
make "name (readword [What is your name?]) show :name
Explained in lesson:
readlist
Prompt the user for a line of input. The result is a list of words.
Example:
make "colors (readlist [Type some colors:]) show :colors
Predicates
word thing , word? thing
Returns true (1) or false (0) if thing is a word
Example:
show word "hello
listp thing , list? thing
Returns true (1) or false (0) if thing is a list
Example:
print listp [1 2 3]
arrayp thing , array? thing
Returns true (1) or false (0) if thing is an array
Example:
print arrayp array 2
numberp thing , number? thing
Returns true (1) or false (0) if thing is a number
Example:
print numberp 25
emptyp thing , empty? thing
Test if thing is an empty list or empty string.
Example:
print emptyp []
equalp expr expr , equal? expr expr
Test if xper expr are equal.
Example:
equalp "no "yes
notequalp expr expr , notequal? expr expr
Test if xper expr are not equal.
Example:
notequalp "no "yes
beforep thing1 , before? thing1
Test string collation order.
Example:
print before? "bye "hi
substringp thing1 thing2 , substring? thing1 thing2
Test if thing1 is a substring of thing2.
Example:
print substringp "hello "helloworld