Language guide

Working with programs
Control flow
Arrays and variables
Type conversion
String operations
Text and the screen
The printer
Keyboard input
Function-key macros
Calculations and maths
- Mathematical functions
- Random numbers
Devices and files
- File operations
- Devices
Graphics
Sound
Joystick and mouse
Disks and DOS
Serial communications
Event handling
Error handling
User-defined functions
Date and time
Including data in a program
Memory and machine ports
Features not yet implemented
Unsupported features

This documentation describes the SE Basic IV language, which aims to support programs written for Microsoft BASIC with minimal changes.

The Language Guide covers the language topic by topic, thematically grouping language elements used for a related purpose. Refer to the Language reference for a formal description of the language elements and their syntax.

Working with programs

Statement	Description
AUTO	Enter automatic line numbering mode
CHAIN	Load a new program and run it, preserving common variables
DELETE	Delete lines from the program
EDIT	Print a program line to the screen for editing
LIST	Print program lines to the screen
LOAD	Read a new program from file
MERGE	Overlay a program file onto the current program
NEW	Clear the current program from memory
RENUM	Replace the program's line numbers
RUN	Start the current program
SAVE	Store the current program to file
TRON	Enable line number tracing
TROFF	Disable line number tracing

Control flow

Statement	Description
CONT	Continue interrupted program
ELSE	Ignore the remainder of the line (standalone ELSE)
END	Stop execution of the program
FOR	Start a for-loop
GOSUB	Call a subroutine
GOTO	Jump to another location in the program
IF	Branch on a condition
NEXT	Iterate a for-loop
ON	Calculated jump or subroutine call
RETURN	Return from subroutine
STOP	Interrupt program execution
WEND	Iterate a while-loop
WHILE	Enter a while-loop

Arrays and variables

Statement	Description
DIM	Allocate an array
ERASE	Deallocate an array
SWAP	Swap two variables

Type conversion

Function	Description
ASC	Character to ordinal value
CHR$	Ordinal value to character
HEX$	Integer to hexadecimal string representation
OCT$	Integer to octal string representation
STR$	Numeric value to decimal string representation
VAL	String representation to numeric value

String operations

Function	Description
LEN	String length

Text and the screen

Statement	Description
CLS	Clear the screen
COLOR	Set colour and palette values
LOCATE	Set the position and shape of the text screen cursor
PALETTE	Assign a colour to an attribute
PALETTE USING	Assign an array of colours to attributes
PRINT	Print expressions to the screen

Function	Description
SCREEN	Character or attribute at given location

The printer

Statement	Description
PRINT #	Print expressions to the printer

Keyboard input

Statement	Description
INPUT	Retrieve user input on the console
LINE INPUT	Retrieve a line of user input on the console

Function	Description
INKEY$	Nonblocking read from keyboard
INPUT$	Blocking read from keyboard

Function-key macros

Statement	Description
KEY	Define a function-key macro

Calculations and maths

Mathematical functions

Function	Description
ABS	Absolute value
ATAN	Arctangent
ACOS	Arccosine
ASIN	Arcsine
COS	Cosine
EXP	Exponential
FIX	Truncation
INT	Floor
LOG	Natural logarithm
SIN	Sine
SGN	Sign
SQR	Square root
TAN	Tangent

Random numbers

Statement	Description
RANDOMIZE	Seed the random number generator

Function	Description
RND	Pseudorandom number

Devices and files

File operations

Devices

SE Basic IV handles devices differently than Microsoft BASIC. A device is connected to a specific channel and one or more I/O streams can be connected to that channel. For example, the display is connected to channel S and by default stream #2 is connected to that channel S.

Graphics

Sound

Joystick and mouse

Disks and DOS

In SE Basic IV, the DOS is integrated into BASIC and there is no SHELL command.

Statement	Description
`CHDIR`	Change current directory.
`COPY`	Make a copy of a file.
`FILES`	List the files in the current directory.
`KILL`	Delete a file on a disk device.
`MKDIR`	Create a new directory.
`NAME`	Rename a file on disk.
`RMDIR`	Remove a directory.