LOGO Primitives

Command	Short Form	Example	Description
Chapters 4 – 8 Procedures
;	;	;	; Tells LOGO that everything on that line is a comment. The Interpreter ignores anything on that line.
PRINT	PR	PR “Hello	Prints one word in the listener window.
		PR [Hello World!]	Prints a list enclosed in [ ] in the listener window. For now consider a list in this example as a sentence.
TO	TO	TO SQUARE	Creates a procedure using the name listed following the word TO.
:	:	:LEN_SIDE	: is used immediately before a local variable name in a procedure.
TURTLETEXT	TT	TT [Hello World!]	Stamps the input word or list at the active turtle’s position in the current pen color and font, when the pen is down.
SETFONT	SETFONT	SETFONT “times 14 1	SETFONT defines the turtle font. The first input is the font name. The second input is the font size, given in points, while the third is a combination of the following attributes: 0 regular 1   bold 2   italic 4   underlined
POTS	POTS	POTS	Displays a list of the procedure titles currently in the workspace.
POPS	POPS	POPS	Displays all user-defined procedures and their definitions currently in the workspace.
PO ALL	PO ALL	PO ALL	Displays everything in the workspace.
ERASE	ER	ER SQUARE	Erases one procedure from the workspace. In the example SQUARE is erased from the workspace.
		ER TRIANGLE SQUARE PENTAGON HEXAGON	Erases all of the procedures listed after the ER command. Each procedure is separated by a space from the other procedures.
ERASE ALL	ER ALL	ER ALL	Erases all procedures currently in the workspace.
PAUSE	PAUSE	PAUSE	Used to “debug” your program. This command will cause the program to stop execution and allow you to “Step” through your program using the Stop Light to trace your program commands.
EDIT	ED	ED SQUARE	Opens the named procedure in the Editor window
EDIT ALL	ED ALL	ED ALL	Opens all of the procedures, all the variables, and all of the contents of the workspace in the Editor Window
LOADPIC	LOADPIC filename.ext	LOADPIC “Harry.bmp	LOADPIC loads the picture file from the disk to the graphics screen. The file is loaded as a bit map which fills the graphics window.
IF THEN	IF THEN	IF :X > 100 THEN STOP	Tests whether the conditional statement (placed between the IF and the THEN) is true or false. If it is true the command after THEN is executed. If false, LOGO continues with the next command line in the procedure.
STOP	STOP	STOP	Causes the current procedure to stop executing and return control to the calling procedure.
TOPLEVEL	TOPLEVEL	TOPLEVEL	Stops the current procedure and all calling procedures, and returns control to the user.