MSLOGO commands

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MSW Logo List Processing Primitive Command Summary

Commands

Shortcut

Action

cleartext

ct
clears the text screen

print i

pr i
prints the item (word, list or result) to the text screen

show i

-
shows the item with " or [] as appropriate

type i

-
holds the item in buffer until print is encountered then prints all

output i

op
returns the value of i to the calling procedure

Constructors

sentence i i

se i i
joins two items (words or lists) together with a space between (as a list)

word i i

-
joins two items (words or letters) together with no space (as a word)

De-Constructors

first i

-
returns the first item of input (a word or list)

butfirst i

bf i
returns everything but the first item of input (a word or list)

last i

-
returns the last item of input (a word or list)

butlast i

bl i
returns everything but the last item of input (a word or list)

item n i

-
returns the nth item of i

Conditional Tests

if (test) [commands]
when test returns "true" does commands and continues, otherwise continues

ifelse (test) [commands][commands]
when test returns "true" does first commands and continues, when test returns "false" does second commands and continues

test (test)
sets flag to "true" or "false"

iftrue [commands]
checks flag before completing commands

iffalse [commands]
checks flag before completing commands

Predicates (some more commonly used ones)

equalp i i

-
returns true if inputs are equal, otherwise returns false

memberp i i

-
returns true if the first i is a member of the second group i, otherwise returns false

emptyp i

-
returns true if the input (word or list) is empty, otherwise returns false

numberp i

-
returns true if the input is number, otherwise returns false

wordp i

-
returns true if the input is a word (not a list), otherwise returns false

listp i

-
returns true if the input is a list (not a word), otherwise returns false

Turtle Graphics

Commands

Shortcut

Action

forward n

fd n
moves the turtle forward n turtle steps

backward n

bk n
moves the turtle backwards n turtle steps

right n

rt n
turns the turtle right n degrees

left n

lt n
turns the turtle left n degrees

repeat

_
eg. repeat 4 [fd 50 rt 90] will draw a square

hideturtle

ht
makes the turtle invisible (it will move much faster when invisible)

showturtle

st
makes the turtle visible

clearscreen

cs
clears the graphics screen and returns the turtle to home position

clean

_
clears the screen but leaves the turtle where it is

home

_
sends the turtle to home position but leaves the drawing as is

cleartext

ct
removes the list of commands from the commander window

penup

pu
lifts the turtle's pen so it doesn't draw when moving

pendown

pd
puts the turtle's pen back down so it will draw when moving

penerase

pe
changes the pen to an eraser

penreverse

px
causes the pen to erase over existing lines, otherwise draw

penpaint

_
returns the drawing version of the pen after erasing or reversing

fence

_
keeps the turtle from wrapping or going off the edge of the window

window

_
keeps the turtle from wrapping and allows it to go out of the window

wrap

_
makes the turtle wrap around the screen when it gets to one edge

setpensize [n n]

_
uses two values for pen size, height and width

setscreencolor [n n n]

setsc [n n n]
sets screen background colour**

setpencolor [n n n]

setpc [n n n]
sets pen colour**

setfloodcolor [n n n]

setfc [n n n]
sets the colour** to fill with if the fill command is used floods the area where the turtle is with the flood colour

Fill

_

setpos [n n]

_
moves the turtle to the x, y coordinates given

setx n or sety n

_
moves the turtle to x or y coordinates given

pos or xcor or ycor

_
outputs the x and y or x or y position of the turtle

Setheading n

seth n
sets the turtle's heading in degrees (0 is up)

towards [n n]

_
outputs the heading the turtle would have if facing x, y given

to procedure

_
eg. to square defines the name of a procedure to teach logo commands

edit procedure

_
takes you to the editor to edit a procedure

:variable_name

_
eg. to square :size sets a variable :size that can be used in square

repcount none the number of times that a procedure has been repeated

PERSPECTIVE none Switch to 3D mode

LEFTROLL n none Rolls the turtle (on to his left side) by n degrees

RIGHTROLL n none Rolls the turtle (on to his right side) by n degrees

UPPITCH n none Pitches the turtle nose up by n degrees

DOWNPITCH n none Pitches the turtle nose up by n degrees

MSW Logo List Processing Primitive Command Summary
Commands	Shortcut	Action
cleartext	ct	clears the text screen
print i	pr i	prints the item (word, list or result) to the text screen
show i	-	shows the item with " or [] as appropriate
type i	-	holds the item in buffer until print is encountered then prints all
output i	op	returns the value of i to the calling procedure
Constructors
sentence i i	se i i	joins two items (words or lists) together with a space between (as a list)
word i i	-	joins two items (words or letters) together with no space (as a word)
De-Constructors
first i	-	returns the first item of input (a word or list)
butfirst i	bf i	returns everything but the first item of input (a word or list)
last i	-	returns the last item of input (a word or list)
butlast i	bl i	returns everything but the last item of input (a word or list)
item n i	-	returns the nth item of i
Conditional Tests
if (test) [commands]		when test returns "true" does commands and continues, otherwise continues
ifelse (test) [commands][commands]		when test returns "true" does first commands and continues, when test returns "false" does second commands and continues
test (test)		sets flag to "true" or "false"
iftrue [commands]		checks flag before completing commands
iffalse [commands]		checks flag before completing commands
Predicates (some more commonly used ones)
equalp i i	-	returns true if inputs are equal, otherwise returns false
memberp i i	-	returns true if the first i is a member of the second group i, otherwise returns false
emptyp i	-	returns true if the input (word or list) is empty, otherwise returns false
numberp i	-	returns true if the input is number, otherwise returns false
wordp i	-	returns true if the input is a word (not a list), otherwise returns false
listp i	-	returns true if the input is a list (not a word), otherwise returns false
Turtle Graphics
Commands	Shortcut	Action
forward n	fd n	moves the turtle forward n turtle steps
backward n	bk n	moves the turtle backwards n turtle steps
right n	rt n	turns the turtle right n degrees
left n	lt n	turns the turtle left n degrees
repeat	_	eg. repeat 4 [fd 50 rt 90] will draw a square
hideturtle	ht	makes the turtle invisible (it will move much faster when invisible)
showturtle	st	makes the turtle visible
clearscreen	cs	clears the graphics screen and returns the turtle to home position
clean	_	clears the screen but leaves the turtle where it is
home	_	sends the turtle to home position but leaves the drawing as is
cleartext	ct	removes the list of commands from the commander window
penup	pu	lifts the turtle's pen so it doesn't draw when moving
pendown	pd	puts the turtle's pen back down so it will draw when moving
penerase	pe	changes the pen to an eraser
penreverse	px	causes the pen to erase over existing lines, otherwise draw
penpaint	_	returns the drawing version of the pen after erasing or reversing
fence	_	keeps the turtle from wrapping or going off the edge of the window
window	_	keeps the turtle from wrapping and allows it to go out of the window
wrap	_	makes the turtle wrap around the screen when it gets to one edge
setpensize [n n]	_	uses two values for pen size, height and width
setscreencolor [n n n]	setsc [n n n]	sets screen background colour**
setpencolor [n n n]	setpc [n n n]	sets pen colour**
setfloodcolor [n n n]	setfc [n n n]	sets the colour** to fill with if the fill command is used floods the area where the turtle is with the flood colour
Fill	_
setpos [n n]	_	moves the turtle to the x, y coordinates given
setx n or sety n	_	moves the turtle to x or y coordinates given
pos or xcor or ycor	_	outputs the x and y or x or y position of the turtle
Setheading n	seth n	sets the turtle's heading in degrees (0 is up)
towards [n n]	_	outputs the heading the turtle would have if facing x, y given
to procedure	_	eg. to square defines the name of a procedure to teach logo commands
edit procedure	_	takes you to the editor to edit a procedure
:variable_name	_	eg. to square :size sets a variable :size that can be used in square
repcount	none	the number of times that a procedure has been repeated
PERSPECTIVE	none	Switch to 3D mode
LEFTROLL n	none	Rolls the turtle (on to his left side) by n degrees
RIGHTROLL n	none	Rolls the turtle (on to his right side) by n degrees
UPPITCH n	none	Pitches the turtle nose up by n degrees
DOWNPITCH n	none	Pitches the turtle nose up by n degrees