BASIC09 (quick Reference

This chapter contains a quick reference of all BASIC09 commands, statements, and functions. It includes commands for pro-

gramming, editing, and debugging, as well as the Commands
 mode commands.

The following chart lists all BASIC09 keywords that you can use in a procedure.


Statements and Functions
Command Description
 ABS Returns the absolute value of a number.
 ACS Calculates the arccosine of a number.
 ADDR Returns an integer value which is the abso
 lute memory address of a variable, array, or
 structure in a process's address space.
 AND Generates the logical AND of two Boolean
 values.
 ASC Returns the ASCII code of the first charac
 ter in a string.
 ASN Calculates the arcsine of a number.
 ATN Calculates the arctangent of a number.
 BASE Sets the lowest array or data structure sub
 script in a procedure to either 0 or 1.
 BYE Ends execution of a procedure and termi
 nates BASIC09.
 CHAIN Executes a module, passing arguments if
 appropriate.
 CHD Changes the current data directory. -
 CHR$ Returns the ASCII character represented by
 a specified integer.
 CHX Changes the current execution directory.
 CLOSE Deallocates the specified path to a file or
 device.
 COs Calculates the cosine of a number.
BASIC09 Reference
Command Description
 CREATE Opens a path and establishes a new file on
 disk. ''
 DATE$ Returns the computer's current date and
 time.
 DEG Causes BASIC09 to calculate angles in
 degrees.
 DATA Stores data in a procedure to be accessed
 by the READ statement.
 DELETE Deletes a file from disk.
 DIM Declares simple variables, arrays or complex
 data structure for size and type.
 DO See WHILE/DO/ENDWHILE.
 ELSE See IF/THEN/ELSE/ENDIF.
 END Terminates execution of a procedure.
 Returns to the calling procedure or to
 BASIC09's command mode. Displays the

 specified text.
 ENDEXIT See EXITIF/ENDEXIT.
 ENDIF See IF/THEN/ELSE/ENDIF.
 ENDLOOP See LOOP/ENDLOOP.
 ENDWHILE See WHILE/DO/ENDWHILE.
 EOF Tests for the end of a disk file.
 ERR Returns the error code of the most recent
 error.
 ERROR Generates the specified error.
 EXITIF/ Tests conditions in a loop. The procedure
 ENDEXIT exits the loop if the condition is true.
 EXP Calculates a (2.71828183) raised to the
 specified value. _
 FALSE A Boolean function that always returns

 FALSE.
 FIX Rounds a real number and converts it to an
 integer.
 FLOAT Converts a byte or integer value to a real
 number.
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 BASIC09 Quick Reference l 10
Command
 FOR/NEXT
Description

Creates a program loop of a specified number of repetitions.


Reads an element or a data structure from a binary file or a device.


Transfers program control to a specified subroutine. RETURN sends execution back to the calling routine.


Evaluates an expression and performs an operation if the conditions are met. Including ELSE causes an alternate operation if the conditions are false.


Stores the character of a keypress in a string variable.


Causes a procedure to accept input from the keyboard or other specified device.


Returns the largest whole number less than or equal to the specified value.


Unlinks a procedure. (Removes it from BASIC09's directory.)


Performs a bit-by-bit logical AND on two-byte, or integer, values.


Returns the specified number of characters, from the leftmost portion of a string.


Returns the length of the specified string.

 Assigns a value to a variable.

Performs a bit-by-bit logical NOT function on two-byte, or integer, values.


Calculates the natural logarithm.

 Calculates a base 10 logarithm.

Establishes a loop. Use EXITIF and ENDEXIT to test the loop and exit when a specified condition is true.


Performs a bit-by-bit logical OR on twobyte, or integer, values.


GET

 GOSUB/
 RETURN
IF/THEN/ELSE/
 ENDIF
INKEY
INPUT
INT
KILL
LAND
LEFT$
LEN
 LET
 LNOT
LOG
 LOG10
 LOOP/
 ENDLOOP
LOR
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 BASIC09 Reference
Command Description
 LXOR Performs a bit-by-bit logical EXCLUSIVE

MID$ Returns the specified number of characters,
 beginning at the specified position in a
 string.
 MOD Returns the modulus (remainder) of a divi
 sion operation.
 NEXT See FOR/NEXT.
 NOT Returns the logical complement of a Boolean
 value.
 ON ERROR/ Traps errors and transfers control to the
 GOTO specified line number.
 ON/GOSUB Evaluates an expression. Then, selects from
 a list the line number that is in the posi
 tion indicated by the result of the expres
 sion. Procedure execution transfers to the
 selected line.
 ON/GOTO Evaluates an expression. Then, selects from
 a list the line number that is in the posi
 tion indicated by the result of the expres
 sion. Procedure execute jumps to the
 selected line.
 OPEN Opens an I/O path to an existing file or
 device.
 OR Performs a logical OR on two Boolean
 values.
 PARAM Describes the parameters a called proce-

PAUSE Suspends execution of a procedure, and
 enters the Debug mode.
 PEEK Returns the byte value of a memory
 address.
 PI Represents the constant 3.14159265.
 POKE Stores a byte value at a specified memory
 address.
 POS Returns the current character position of
 the print buffer.

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Command Description
 PRINT Sends the specified characters or values to
 the display.
 PRINT USING Sends characters or values to the display,
 using the specified format.
 PRINT# Sends the specified characters or values to
 the specified path.
 PRINT# USING Sends characters or values to the specified
 path using the specified format.
 PUT Writes data to a random access file.
 RAD Causes BASIC09 to calculate angles in
 radians.
 READ Accesses data from procedure DATA lines or
 from files or devices.
 REM Indicates that the following characters in a
 procedure line are comments and are not to
 be executed. Also use (* *), or (*.
 REPEAT/UNTIL Establishes a loop that executes until the
 specified condition is met.
 RESTORE Restores the DATA pointer to the first data
 item or to a specified line.
 RETURN See GOSUB/RETURN.
 RIGHT$ Returns the number of characters specified,
 from the rightmost portion of a string.
 RND Returns a random number from a specified
 range.
 RUN Calls another procedure for execution.
 SEEK Changes the file pointer address.
 SGN Determines the sign of a number.
 SHELL Calls an OS-9 command or program for
 execution.
 SIN Calculates the sine of a specified value.
 SIZE Returns the number of bytes assigned to a
 variable, array, or complex data structure.
 SQ Calculates a value raised to the power of
 two.
 10-5
 BASIC09 Reference
Command Description
 SQR/SORT Calculates the square root of a positive
 number. ~"1
 STEP Sets the size of increment in a FOR/NEXT
 loop.
 STOP Terminates the execution of all procedures
 and returns to the BASIC09 Command
 mode.
 STR.$ Converts numeric data to string data.
 SUBSTRING Returns the starting position of a sequence
 of characters in a string.
 SYSCALL Executes an OS-9 System Call.
 TAB Begins a print operation at the specified
 column.
 TAN Calculates the tangent of a value.
 TRIM$ Strips trailing spaces from the specified
 string.

 TRON/TROFF Turn the trace mode on and off.

 TRUE Returns the Boolean value of TRUE.
 TYPE Defines a new data type.
 UNTIL See REPEAT/UNTIL.
 USING See PRINT USING.
 VAL Converts a string to an integer.
 WHILE/DO/ Executes a loop as long as a specified condi
 ENDWHILE tion is true.
 WRITE Writes data in ASCII format to a file or
 device.
 XOR Performs a logical EXCLUSIVE OR on two
 Boolean values.

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                  BASIC09 Quick Reference l 10


Commands by Type

 Statements
BASE 0 DIM GOSUB OPEN RETURN
 BASE 1 ELSE GOTO PARAM RUN
 BYE END IF/THEN PAUSE SEEK
 CHAIN ENDEXIT INPUT POKE SHELL
 CHD ENDIF KILL PRINT STOP
 CHX ENDLOOP LET PUT TROFF
 CLOSE ENDWHILE LOOP RAD TRON
 CREATE ERROR NEXT READ TYPE
 DATA EXITIF/THEN ON ER.RORJGOTO REM UNTIL
 DEG FOR/TO/STEP ON/GOSUB REPEAT WHILE/DO
 DELETE GET ON/GOTO RESTORE WRITE

 Transcendental Functions
 ACS Cos LOG10 SIN
 ASN EXP PI TAN
 ATN LOG
 Numeric Functions

    ABS LAND MOD SQ

    FIX LNOT RND SQR

    FLOAT LOR SGN SQRT

    INT LXOB


String Functions
    ASC LEFT$ RIGHT$ TRIM$

    CHR$ LEN STR$ VAL

    DATE$ MID$ SUB STR

    INKEY


Miscellaneous Functions
    ADDR FALSE SIZE SYSCALL

    EOF PEEK TAB

    ERR POS TRUE


r

                                    10-?

BASIC09 Reference
Data Types

The following list shows the BASIC09 data type you can specify when defining a variable.


Type Function
 BOOLEAN Returns TRUE or FALSE
 BYTE Specifies that a numeric variable is to store
 single-byte values.
 INTEGER Specifies that a numeric variable is to store
 integer (two-byte) values.
 REAL Specifies that a numeric variable is to store
 real (five-byte) values.
 STRING Specifies that a variable is to store ASCII
 characters.

 Types of Access for Files

You can use the following parameters with the CREATE and OPEN commands. Check the individual commands for information on which parameter to use with which command.


Parameter Function
 DIR Lets BASIC09 access a directory-type file
 for reading. Do not use with UPDATE or
 WRITE.
 EXEC Lets BASIC09 access the current execution
 directory rather than the current data
 directory.
 READ Sets the file access mode for reading.
 WRITE Sets the file access mode for writing.
 UPDATE Sets the file access mode for both reading
 and writing.

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                  BASIC09 Quick Reference l 10


Command Mode

 The following chart lists the commands available from the
 BASIC09 Commands mode:

 Command Function
 $ Calls the shell command interpreter to exe-
            cute an OS-9 command.

BYE or Returns you to the OS-9 system or to the
 CTRL BREAK program that called BASIC09.
 CHD Changes the current data directory.
 CHX Changes the current execution directory.
 DIR Displays the name, size, and variable stor
 age requirement of each procedure in the
 workspace.
 EDIT or E Enters the procedure editor/compiler mode
 KILL Removes one or more procedures from the
 workspace.
 LIST Displays a formatted listing of one or more
 procedures.
 LOAD Loads all procedures from a file into the
 workspace.
 MEM Displays current workspace size or reserves
 a specified amount of memory for the
 workspace.
 PACK Performs a second compilation and stores
 the resulting file in the execution directory.
 RENAME Changes a procedure's name.
 RUN Causes a procedure to execute.
 SAVE Writes one or more procedures to disk.

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 BASIC09 Reference
Edit Commands
The following chart lists the commands available from the Edit mode:

 Command Function
 ENTER Moves the edit pointer to the next line.
 + num Moves the edit pointer forward a specified
 number of lines.
 + * Moves the edit pointer past the last line.
 - num Moves the edit pointer back a specified
 number of lines.
 - * Moves the edit pointer to the first line.
 text A space followed by text inserts an unnum
 bered line before the current line.
 line Typing a line number with or without text
 following it inserts the line into the
 procedure.
 line ENTER Moves the edit pointer to the line line.
 cl strllstr2l Changes the text strl to the text str2.
 c*l strllstr2 Changes all occurrences of strl to str2.
 d Deletes the current line.
 d* Deletes all the lines in the procedure.
 1 Lists the current line.
 1* Lists all the lines in the current procedure.
 q Terminates the edit session.
 r Renumbers lines from the first line number,
 in increments of 10.
 r* Renumbers all numbered lines in incre
 ments of 10. The first line number is 100.
 r line Renumbers lines from line in increments- of
 10.
 r line n um Renumbers lines from line, in increments of
 num.
 sl str Searches for the first occurrences of str.
 s*l str Searches for all occurrences of str.

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                  BASIC09 Quick Reference l 10


Debug Commands

The following table lists all the Debug commands and what they accomplish:


Command Function
 $command Tells BASIC09 to execute the specified OS-9
 command or program.
 BREAK Sets a breakpoint at the specified
 procedure.
 CONT Causes procedure execution to continue.
 DEG/R,AD Selects either degrees or radians as the unit
 of angle measurement for trigonometric
 functions.
 DIR Displays the procedures in the workspace.
 Q Leaves the Debug mode for the System
 mode.
 LET Assigns a new value to a variable.
 LIST Displays a source listing of the suspended
 procedure.
 PRINTvar Displays the value of the specified variable.
 STATE Lists the nesting order of all active
 procedures.
 STEPnum Causes execution of the suspended proce
 dure in specified increments.
 TRON/TROFF Turns the trace function on and off.

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