Apple2 Applesoft Basic Reference

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Apple II Programmer's Reference: Applesoft Commands

 

 

APPLESOFT Reference
Statements and Lines
A line typed without a line number is executed immediately; those lines typed with a line number are saved for execution with the RUN command.
:	Separates multiple statements on the same line.
REM	Designates a remark for comments.
Operations on Whole Programs
NEW	Erases the current program and clears all variables.
CLEAR	Resets all variables.
LIST	Displays the entire current program.
LIST 11-12	Displays the lines from 11 to 12.
RUN	Executes the current program.
RUN n	Executes the current program from line n.
LOAD	Loads a program from the cassette I/O port.
SAVE	Saves a program to the cassette I/O port.
Variables
Real	AB	+/- 9.9999999 E+37
Integer	AB%	+/- 32767
String	AB$	0 to 255 characters
Arrays
Real	AB(x,y,z)
Integer	AB%(x,y,z)
String	AB$(x,y,z)
Where A is a letter, B is a letter or digit. The size of an array is limited only by the available memory.
DIM a (x,y,z)	Defines the array a with maximum subscripts of x, y and z.
Arithmetic Operators
=	Assigns a value to a variable
-	Subtraction
+	Addition
/	Division
*	Multiplication
^	Exponentiation
Logical Operators
AND	Both true
OR	Either one or both true
NOT	Is false
Relational Operators
=	Equal to
<	Less than
>	Greater than
<= =<	Less than or equal to
>= =>	Greater than or equal to
<> ><	Not equal to
Arithmetic Functions
ABS(x)	Absolute value of x
SGN(x)	-1 if x<0, 0 if x=0, 1 if x>0
INT(x)	Integer portion of x
SQR(x)	Square root of x
SIN(x)	Sine of x
COS(x)	Cosine of x
TAN(x)	Tangent of x
ATN(x)	Arctangent of x
EXP(x)	e raised to the xth power
LOG(x)	Natural logarithm of x
RND(x)	if x>0, random number between 0 and 1 if x=0, repeats last random number if x<0, begins new repeatable sequence
DEF FN (x) = expr	Defines a function
String Operations
+	Concatenates Strings
LEN(s)	Length of string s
LEFT$(s,x)	Leftmost x characters of string s
MID$(s,x,y)	y characters from s, beginning at position x
RIGHT$(s,x)	Rightmost x characters of string s
STR$(x)	String representing x
VAL(s)	Numeric value of string s
CHR$(x)	Character with ASCII code x
ASC(s)	ASCII code for first character in string s
Control
GOTO n	Branches to line n
ON expr GOTO n1,n2,n3...	Branches to line n1,n2,n3...depending on the value of expr
IF cond THEN s1:s2:s3	Executes statements s1,s2,s3...if expr is true
IF expr GOTO line	Shorthand for "IF expr THEN GOTO line", but the interpreter remembers the syntax (it doesn't tokenize it as an if-then-goto, but rather as if-goto)
FOR v=x TO y STEP z	Begins a loop for all values of v from x to y by z; if step is omitted, 1 is understood.
NEXT v	Repeats loop for next value of v
GOSUB n	Branches to subroutine at line n
RETURN	Returns to point of call from a subroutine
ON expr GOSUB n1,n2,n3...	Branches to subroutine at line n1,n2,n3...depending on the value of expr
POP	Removes one address from the return stack
ONERR GOTO n	Sets the line number branched to when an error occurs.
RESUME	Re-executes statement causing an error.
STOP	Halts program and print line number
CONT	Resumes program execution
END	Halts program execution
Utility Statements
PEEK(addr)	Value of memory location addr
POKE addr,x	Sets memory location addr to x
CALL addr	Executes machine language routine at addr
USR(x)	Passes argument to machine language routine
HIMEM:addr	Sets highest available memory to addr
LOMEM:addr	Sets lowest available memory to addr.
FRE(0)	Amount of available storage
TRACE	Displays the number of each executed line
NOTRACE	Turns line numbering off
Graphics
GR	Sets lores graphics mode and clears screen
COLOR=x	Sets lores drawing color to x
PLOT x,y	Draws a dot at location x,y
HLIN x1,x2 at y	Draws a horizontal line from x1,y to x2,y
VLIN y1,y2 at x	Draws a vertical line from x,y1 to x,y2
SCRN(x,y)	Color on the screen at x,y
HGR	Displays hires page1, mixed mode.
HGR2	Displays hires page2, full screen graphics
HCOLOR=x	Sets hires drawing color to x
HPLOT x,y	Plots a dot at coordinate x,y
HPLOT x1,y1 TO x2,y2	Draws a hires line from x1,y1 to x2,y2
DRAW n AT x,y	Draws shape n at coordinate x,y
XDRAW n AT x,y	Draws shape n at x,y using exclusive-or
SCALE=x	Sets scale to x for shape drawing
ROT=x	Sets rotation to x for shape drawing
Input/Output
IN# n	Re-directs input from slot number n
INPUT s;x,y,...	Prompts with string s, then reads x,y,...
GET c	Reads a single character from keyboard
READ x,y,...	Reads values from DATA list into x,y,...
DATA x,y,...	List of data value
RESTORE	Restarts DATA list from beginning
PDL(n)	Value of paddle n, either 0 or 1
PR# n	Re-directs output to slot number n
PRINT x,y,...	Prints values x,y,...
?	Shorthand for PRINT
TEXT	Sets text mode
HOME	Clears the text screen
HTAB x	Sets cursor horizontal to x
VTAB x	Sets cursor vertical to x
INVERSE	Sets text printing to black on white
NORMAL	Sets text printing to white on black
FLASH	Makes text flash on screen