MockBasic documentation

Documentation for MockBasic version 1

Line labels:

A line label can either be an alphanumeric string (first character must be alphabetic) followed by a colon, or a number. Labels used by the library modules begin with the underline ('_') character.

Variables:

A variable name is an alphanumeric string (first character must be alphabetic). Variables used by the library modules begin with the underline ('_') character. All vaues are long (32-bit) integers.

Values:

Values are long (32-bit) signed integers, and may either be specified in decimal, hexadecimal (with a '$' character as a prefix), or as up to four ASCII characters (in single quotes). Quoted strings evaluate to their address in the program.

Statements:

Statements may be separated on the same line by the ':' character. Statements may not be split between lines.

BEEP
This is the equivalent of "PRINT CHR$(7);", which is the equivalent of "TOOLBOX SysBeep(8)". This statement causes the 'INOUT' library module to be loaded.
BTNWAIT
Generates code using the 'Button' toolbox call to wait for the mouse button to be pressed and released. Does not prevent mouse-up & mouse-down events from being generated.
CLS
Clears the current grafport with the 'EraseRect' toolbox call. The same effect can be generated with "PRINT CHR$(12);". This statement causes the 'INOUT' library module to be loaded.
DATA dataval [ , dataval [ , ... ] ]
Causes data that can be read in with the READ statement to be embedded in the program's code. 'dataval' can either be a number, a string (in double quotes), or the keyword 'END'. See 'READ' for more information.
DEBUG [ ( expr ) ]
This is used to call up the MacsBug debugger with the 'Debugger' toolbox call. If no expression is given, the word 'A9FF' is added to the code. If an expression is given, it will be evaluated and pushed on the stack, and the word 'ABFF' is added to the code. 'expr' is usually a literal double quoted string.
DO statement [ statement ... ] DOEND
The 'DO' statement causes a block of statements to be treated as a single statement by such keywords as 'FOR', 'IF', 'WHILE', and 'UNTIL'.
DO NOTHING
This doesn't work properly yet, but when it does, it will be equal to a 'DO: DOEND' pair with nothing inside. This doesn't have much use except for something like:

UNTIL INKEY DO NOTHING
DOEND
See 'DO'.
DOWNTO
See 'FOR'.
ELSE
See 'IF'.
END
Causes the word 'A9F4' (the ToolBox call 'ExitToShell') to be added to the code. This will cause the program to exit to the Finder.
FOR variable = expr1 TO/DOWNTO expr2 [ STEP expr3 ] statement
The variable is set to the value of 'expr1', and the statement is executed until 'expr2' is reached. If no 'STEP' is given, either 1 (for 'TO') or -1 (for 'DOWNTO') is used. Note: 'expr2' is evaluated every time through the loop, causing the statement to be equivalent to a 'WHILE' statement in the following way:

FOR x=1 TO i+1 PRINT x

is equivalent to

x=1: WHILE (i+1)<10 DO PRINT x: x=x+1: DOEND

Note that it is possible for the statement to not be executed at all, as in the case of:

FOR x=1 TO 0 PRINT x
FREE expr
'expr' must be a pointer to a block of memory allocated with the 'NEW' function. This statement frees up the memory using the 'DisposePtr' ToolBox call.
GOSUB label
Causes the code at the specified label to be executed as a subroutine. Execution is transferred to the label, and a 'RETURN' statement returns back to the statement after the 'GOSUB'.

The code generated for this statement is: LEA label(PC),A0 BSR.W _GOSUB The code for '_GOSUB' is: LINK A6,#0 JMP (A0) The reason for this is 1) it is not possible to determine if a label begins a subroutine or not, so it is not possible to use the LINK instruction to create the stack frame at the subroutine, and 2) I want to have a stack frame for subroutines, because this allows the 'RETURN' command to return from procedures and functions (when they get implemented).
GOTO label
Transfers control to the specified label.
IF expr THEN statement1 [ ELSE statement2 ]
Evaluates 'expr', and if it is non-zero, statement1 is executed. If the value is zero, statement2 is executed.
ILLEGAL
Adds the word '4AFC' (the offical illegal instruction for the 68000) to the program's code. This can be useful for debugging programs, but 'DEBUG' will probably be more useful.
[ LET ] variable = expr
Evaluates 'expr' and stores it in the variable.
LOCATE row , column
Uses the 'MoveTo' ToolBox call to go to the specified character position in the current GrafPort. The 'GetFontInfo' call is used to determine the character size, and the maxWidth of the font is used to compute the column's width. This statement causes the 'INOUT' library module to be loaded.
LPOKE expr1 , expr2
Evaluates 'expr2' and stores it as a long (32-bit) integer into the address specified by 'expr1'. Because the 'MOVE.L' instruction is used, 'expr1' must be an even address.
NOP
Adds the word '4E71' to the program's code. This is the 68000 'NOP' instruction, and can be useful during debugging to reserve some space for patching the program when in the debugger.
POKE expr1 , expr2
Evaluates 'expr2' and stores it as a byte (8 bits) into the address specified by 'expr1'.
PRINT [ expr [ ; expr ] ] [ ; ]
Prints the expressions out to the current GrafPort, in decimal, with no leading or trailing blanks. After printing out all of the expressions, the pen position is moved to the next line, unless the trailing semicolon is used. 'expr' can also be one of the following:
- CHR$(expr)
  Prints an ASCII character to the current GrafPort
- STRING(expr)
  Prints a Pascal type string from the address 'expr'
This statement causes the 'INOUT' library module to be loaded.
PSTR expr
Prints a Pascal type string from the address 'expr'. The use of "PRINT STRING(expr)" is preferred. This statement causes the 'INOUT' library module to be loaded.
READ [ variable [ , variable [ , ... ] ]
Reads in values from 'DATA' statements in the program. The global variable '_DATATYPE' is set according to the type of data read in.
- type / from / value assigned to variable
- -1 / END / 0
- 0 / number / The number's value
- 1 / string / The address of the string
Note that a '_DATATYPE' of -1 can either be from the program running out of 'DATA' statements, or from an 'END' keyword in a 'DATA' statement. This statement causes the 'READ' library module to be loaded.
RESTORE [ label ]
Sets the 'DATA' statement pointer to the specified label, or the beginning of the program if none specified. Also see 'READ'. If 'label' is specified, this statement causes the 'READ' library module to be loaded.
RETURN
Returns from a 'GOSUB' call.
STEP
See 'FOR'.
THEN
See 'IF'.
TO
See 'FOR'.
TOOLBOX name [ ( expr [ , expr [ , ... ] ] ) ] [ , variable [ , variable ] ]
Calls the specified ToolBox call. The parameters are in 'expr', and any return values either put into a variable, ignored, or put into the global variable '_OSErr'. If you wish a return variable to be ignored, you must specify 'NIL' instead. Note that the parameters used in the 'TOOLBOX' statement may not be identical to the way that they are specified in Inside Macintosh, and are instead halfway between the Pascal and assembly language methods. The two examples are 'FlushEvents' and 'CmpString'. The 'TOOLBOX' call has only one parameter because only one register is used by the routine, and the 'TOOLBOX' statement does not have the capability to combine two values into the same register. Note that the paramBlock OS calls do not have the characters 'PB' in front of their names. Example: PBREAD is called by TOOLBOX READ(paramBlock).
UNTIL expr statement
Executes 'statement' until 'expr' is non-zero. Note that 'statement' will be executed at least once because the test is done after 'statement'.
WHILE expr statement
Executes 'statement' while 'expr' is non-zero. Note that 'statement' might not get executed because the test is done before 'statement'.
WPOKE expr1 , expr2
Evaluates 'expr2' and stores it as a word (16 bits) into the address specified by 'expr1'. Because the 'MOVE.W' instruction is used, 'expr1' must be an even address.

Functions:

- expr
Returns the negative (two's complement) of 'expr'.
@ variable
Returns the address of the variable.
@@ label
Returns the address of the label.
ABS ( expr )
Returns the absolute value of 'expr'.
ASL ( expr1, expr2 )
Shifts 'expr1' left by 'expr2' bits. Note that this is equivalent to multiplying by a power of two.
ASR ( expr1 , expr2 )
Arithmetic shifts 'expr1' right by 'expr2' bits. Note that this is equivalent to dividing by a power of two.
BUTTON
Calls the ToolBox function 'Button' and returns the value from 'Button'.
INKEY
This function calls the ToolBox function 'GetNextEvent' with an event mask for keyDown and autoKey events. If no key events are pending, zero is returned. The 'modifiers' field of the event record is copied into the global variable '_MODIFIERS'. This statement causes the 'INOUT' library module to be loaded.
LSR ( expr1 , expr2 )
Shifts 'expr1' right by 'expr2' bits.
LPEEK ( expr )
Returns the longword at the address specified by 'expr'. Because the 'MOVE.L' instruction is used, 'expr1' must be an even address.
NIL
Returns zero. Sorry, but comparisons against NIL are only comparing against zero. A later version will only compare the low three bytes in a direct comparison against NIL.
NEW ( expr )
Calls the ToolBox function '_NewPtr ,CLEAR' to allocate the specified number of bytes of memory. The address of the new memory is returned by this function, and the memory can later be freed with the 'FREE' statement.
NOT expr
Returns the one's complement of the expression.
PEEK ( expr )
Returns the byte at the address specified by 'expr'.
SGN ( expr )
Returns the arithmetic sign of 'expr' (-1, 0, or 1)
WPEEK ( expr )
Returns the word at the address specified by 'expr'. The word is then sign extended. Because the 'MOVE.W' instruction is used, 'expr1' must be an even address.

Operators:

& or AND Returns the bitwise AND of the two operands.
| or OR Returns the bitwise OR of the two operands.
XOR Returns the bitwise XOR of the two operands.
+ Adds the two operands together.
- Subtracts the second operand from the first operand.
* Multiplies the two operands together.
/ or DIV Divides the first operand by the second operand.
% or MOD Returns the remainder of dividing the operands.

Comparisons:

The comparisons return zero if false, and -1 if true.

= True if the operands are equal.
< True if the first operand is less than the second.
≤ <= =< True if the first is less than or equal to the second.
> True if the first operand is greater than the second.
≥ => >= True if the first is greater than or equal to the second.
≠ <> >< True if the operands are not equal.

Documentation for MockBasic version 1

Line labels:

Variables:

Values:

Statements:

BEEP

BTNWAIT

CLS

DATA dataval [ , dataval [ , ... ] ]

DEBUG [ ( expr ) ]

DO statement [ statement ... ] DOEND

DO NOTHING

DOEND

DOWNTO

ELSE

END

FOR variable = expr1 TO/DOWNTO expr2 [ STEP expr3 ] statement

FREE expr

GOSUB label

GOTO label

IF expr THEN statement1 [ ELSE statement2 ]

ILLEGAL

[ LET ] variable = expr

LOCATE row , column

LPOKE expr1 , expr2

NOP

POKE expr1 , expr2

PRINT [ expr [ ; expr ] ] [ ; ]

CHR$(expr)

STRING(expr)

PSTR expr

READ [ variable [ , variable [ , ... ] ]

RESTORE [ label ]

RETURN

STEP

THEN

TO

TOOLBOX name [ ( expr [ , expr [ , ... ] ] ) ] [ , variable [ , variable ] ]

UNTIL expr statement

WHILE expr statement

WPOKE expr1 , expr2

Functions:

- expr

@ variable

@@ label

ABS ( expr )

ASL ( expr1, expr2 )

ASR ( expr1 , expr2 )

BUTTON

INKEY

LSR ( expr1 , expr2 )

LPEEK ( expr )

NIL

NEW ( expr )

NOT expr

PEEK ( expr )

SGN ( expr )

WPEEK ( expr )

Operators:

Comparisons: