Simons' BASIC

Features

The 114 keywords

Sprite (MOB) handling keywords

• MOB SET – enables a sprite and defines its attributes
• MMOB – positions a sprite on the screen
• RLOCMOB – causes a sprite to smoothly move from one location to another
• CMOB – sets up the two global colors for multicolor sprites
• MOB OFF – disables a sprite
• DETECT – initializes sprite collision detection
• CHECK – checks for a sprite collision

  High resolution graphics handling keywords

• HIRES – initializes a high-resolution graphics mode
• MULTI – initializes a multicolor graphics mode
• NRM – returns to the text display
• LOW COL – changes the plotting colors
• HI COL – returns to the original plotting colors
• PLOT – draws a pixel
• LINE – draws a line
• CIRCLE – draws a circle
• ARC – draws an arc
• ANGL – draws the radius of a circle
• PAINT – performs a flood fill
• REC – draws a hollow rectangle
• BLOCK – draws a solid rectangle
• DRAW – draws a user-defined set of lines
• ROT – sets scaling factors for DRAW
• CHAR – plots a text character on a high-resolution screen
• TEXT – plots a text string on a high-resolution screen
• TEST – determines whether a pixel is plotted or empty

  Other graphics handling keywords

• COLOUR – sets the background and border colors.
• CSET – selects a character set
• MEM – copies character ROM to RAM
• BCKGNDS – configures extended background color mode
• FLASH – sets up a screen color to flash
• OFF – cancels a previous FLASH directive
• BFLASH – causes the screen border to flash
• FCHR – fills an area of the text screen with a given character code
• FCOL – changes character colors for a selected area of the screen
• FILL – a combination of FCHR and FCOL
• MOVE – copies a section of the screen
• INV – displays a screen area in reverse
• LEFT – scrolls the screen left
• RIGHT – scrolls the screen right
• UP – scrolls the screen up
• DOWN – scrolls the screen down
• GRAPHICS – reserved variable that always equals $D000
• SCRSV – saves a text screen to tape or disk
• SCRLD – loads a text screen from tape or disk

  Sound handling keywords

• MUSIC – plays a series of notes based on the contents of a string variable
• PLAY – determines whether the program continues to run during MUSIC
• VOL – specifies the master sound volume
• WAVE – specifies a voice type
• ENVELOPE – sets ADSR parameters for a SID voice
• SOUND – reserved variable that always equals $D400

  Keyboard input handling keywords

• FETCH – takes user input with restrictions defined by the command
• INKEY – checks for a function key press
• ON KEY – checks for a given keypress, then performs a branch if present
• DISABLE – disables the previous ON KEY directive
• RESUME – reenables the previous ON KEY directive

  Input peripheral handling keywords

• JOY – reads a joystick
• POT – reads a paddle
• PENX – reads the light pen's horizontal position
• PENY – reads the light pen's vertical position

  Sprite/custom character definition keywords

• @ – describes one line in a sprite or custom character graphic
• DESIGN – uses neighbouring @ lines to define a sprite or custom character

  Error trapping keywords

• ON ERROR – sets up a routine to trap error conditions
• OUT – ends an error handling routine
• NO ERROR – cancels ON ERROR and restores normal BASIC error handling

  Disk handling keywords

• DIR – displays the disk directory without destroying the BASIC program in memory
• DISK – sends a string to the disk drive's command channel

  Printer handling keywords

• HRDCPY – sends the text screen to the printer
• COPY – sends the high-resolution screen to the printer

  String manipulation keywords

• INSERT – inserts one string into the middle of another
• INST – similar to INSERT, but overwrites rather than inserting.
• PLACE – searches for one string in the middle of another
• DUP – duplicates a character string a given number of times.

  Text formatting keywords

• PRINT AT – prints a string at a given screen location
• CENTRE – centers a character string on the screen.
• USE – formats numeric data in strings based on a template, just like PRINT USING on other advanced versions of BASIC on other computers, e.g. the Commodore 128, for example.
• LIN – returns the vertical position of the cursor

  Maths keywords

• MOD – performs a division operation and returns the remainder
• DIV – performs a division operation and returns the integer quotient
• FRAC – isolates the fractional portion of a number
• EXOR – performs an exclusive-OR logical operation

  Programmer's aid keywords

• AUTO – automatically generates line numbers as a BASIC program is entered
• RENUMBER – renumbers a BASIC program
• OLD – undeletes a program accidentally removed by the NEW command
• KEY – assigns a string as a macro to a function key
• DISPLAY – displays all function key macros
• MERGE – merges a BASIC program from tape or disk into the program currently in memory
• PAGE – displays a BASIC program listing in page format
• OPTION – highlights Simons' BASIC keywords when using the LIST command
• DELAY – varies the rate at which the LIST command scrolls the screen
• FIND – searches the program for a string
• TRACE – displays the line numbers as a program is running
• RETRACE – displays results of a trace
• DUMP – displays all variable values except for arrays
• COLD – resets the C64

  Security-related keywords

• DISAPA – marks a BASIC program line for hiding
• SECURE – hides all lines marked with DISAPA so that they cannot be viewed with LIST

  Structured programming keywords

• ELSE – allows an alternative branch for IF/THEN conditionals
• REPEAT – start of a REPEAT/UNTIL loop structure
• UNTIL – defines the loop condition for a REPEAT/UNTIL loop structure, and marks its end
• RCOMP – reinstates the most recently used IF/THEN/ELSE conditional
• LOOP – defines the start of a loop that will run until an EXIT IF conditional is true
• EXIT IF – the conditional is true, so it exits the current LOOP/END LOOP structure
• END LOOP – defines the end of a loop that will run until an EXIT IF conditional is true
• PROC – defines the start of a named subroutine
• END PROC – defines the end of a named subroutine
• CALL – jump to a named subroutine defined with PROC/END PROC, and stay there
• EXEC – call a named subroutine defined with PROC/END PROC, then return
• LOCAL – redefines variables for use in structures
• GLOBAL – reverses the effects of a previous LOCAL command

  Miscellaneous keywords

• CGOTO – equivalent to GOTO, but accepts calculated expressions
• RESET – moves the DATA pointer to a given line number
• PAUSE – pauses program execution for a specified number of seconds

  Other

• $ and % are also considered keywords, for a total of 114.

  Trivia

Reception