Sinclair BASIC is a dialect of the programming language BASIC used in the 8-bit home computers from Sinclair Research and Timex Sinclair. The Sinclair BASIC interpreter was made by Nine Tiles Networks Ltd.^[1]

History

Sinclair BASIC was originally developed in 1979 for the ZX80 by Nine Tiles. The programmers were John Grant, the owner of Nine Tiles, and Steve Vickers.

It was initially an incomplete implementation of the 1978 American National Standards Institute (ANSI) minimal BASIC standard with integer arithmetic only, termed 4K BASIC (for its ROM size) for the ZX80. It evolved through the floating-point 8K BASIC for the ZX81 and T/S 1000 (which was also available as an upgrade for the ZX80^[2]), and became an almost complete version in the 16 KB ROM ZX Spectrum (known as 48K BASIC).

It is present in all ZX Spectrum compatibles and clones, with more advanced systems also offering expanded versions like 128K BASIC, +3 BASIC, T/S 2000 BASIC, BASIC64 or Timex Extended Basic.

As of 2015, interpreters exist for modern operating systems,^[3] and older systems,^[4] that allow Sinclair Basic to be used easily.

Syntax

Keywords

On the 16K/48K ZX Spectrum (48K BASIC), there are 88 keywords in Sinclair BASIC, denoting commands (of which there are 50), functions and logical operators (31), and other keywords (16, including 9 which are also commands or functions):

Keyword	Parameters[note 1]	Entered using[note 2]	Type	Summary
ABS	number	EXTENDED MODE then G	Function	Returns the absolute value of number[5]
ACS	number	EXTENDED MODE then SYMBOL SHIFT+W	Function	Returns the arccosine of number[6]
AND		SYMBOL SHIFT+Y	Logical operator	Returns true if both conditions on either side of the AND keyword are true, else returns false[note 3][7]
ASN	number	EXTENDED MODE then SYMBOL SHIFT+Q	Function	Returns the arcsine of number[8]
AT	line, column;	SYMBOL SHIFT+I	Other	Used in a PRINT statement to print at the line and column specified;[9] for example, PRINT AT 5,10;"*" puts a star in column 10 of line 5.
ATN	number	EXTENDED MODE then SYMBOL SHIFT+E	Function	Returns the arctangent of number[6]
ATTR	(line, column)	EXTENDED MODE then SYMBOL SHIFT+L	Function	Returns a byte containing information on the colours of the text cell on the screen, corresponding to the specified line and column;note that, unlike most Sinclair BASIC keywords, the parentheses are required; the first three bits indicate the ink (foreground)colour, the fourth, fifth and sixth bits the paper (background) colour, the seventh bit whether the colours are bright or not, and the eight, whether they are flashing[10]
BEEP	duration, pitch	EXTENDED MODE then SYMBOL SHIFT+Z	Command	Produces sound from the computer's speaker; duration is in seconds, pitch is in semitones above (positive value) or below (negative value) middle C[11]
BIN	number	EXTENDED MODE then B	Other	Indicates number is in binary notation[12]
BORDER	number	B	Command	Sets the border of the screen to the colour specified by the number[note 4][13]
BRIGHT	number	EXTENDED MODE then SYMBOL SHIFT+B	Command/other	Makes all following colours brighter if number is 1, or its normal shade if 0[note 5][14]
CAT	number	EXTENDED MODE then SYMBOL SHIFT+9	Command	Displays contents of ZX Microdrive specified by number[note 6][15]
CHR$	number	EXTENDED MODE then U	Function	Returns the character corresponding to the decimal number in the computer's character set[16]
CIRCLE	x, y, r	EXTENDED MODE then SYMBOL SHIFT+H	Command	Draws a circle with its centre at coordinates (x,y) and radius r[17]
CLEAR	address	X	Command	Clears the screen,[18] all variables and the GO SUB stack,[19] and optionally sets the maximum RAM address to be used by BASIC[20]
CLOSE #	number	EXTENDED MODE then SYMBOL SHIFT+5	Command	Closes the specified stream number for access[note 6]
CLS		V	Command	Clears all text and graphics from the screen[18]
CODE	string	EXTENDED MODE then I	Function/other	Returns the number corresponding to the first character in string in the computer's character set;[16] also used to save arbitrary chunks memory to tape, disk, etc. and load them back in — see LOAD, SAVE and VERIFY for details
CONTINUE		C	Command	Restarts a program after it has stopped due to an error or the user pressing the CAPS SHIFT+SPACE or BREAK keys[21]
COPY		Z	Command	Sends the currently displayed screen to the printer[22]
COS	number	EXTENDED MODE then W	Function	Returns the cosine of number[23]
DATA	comma-separated values	EXTENDED MODE then D	Command/other	Provides numbers and/or strings to use with the READ command[24] and allows saving the contents of an array to tape when used with the SAVE command[25] (as SAVE filename DATA array name()
DEF FN	name(variable) = operation	EXTENDED MODE then 1	Command	Defines a custom function that can be used with the FN command;function definitions must be of the form f(x)=operations, for example f(x)=x*2 and the function name may not consist of more than one letter, plus a $-symbol if the function returns a string[26]
DIM	variable(dimensions)	D	Command	Declares an array with the specified dimensions, which may be multi-dimensional (for example, DIM a(10,10); if used with strings, the last dimension indicates the length of each of the strings (thus, DIM a$(2,5) is an array of two strings each of five characters long, and DIM b$(5) is one string of five characters)[27]
DRAW	x, y [, r]	W	Command	Draws a line in the current INK colour to coordinates (x,y) from the coordinates used by the previous PLOT or DRAW command; if the optional r is supplied, it indicates the radius of the circle segment to be drawn, in radians[28]
ERASE	drive;"filename"	EXTENDED MODE then SYMBOL SHIFT+7	Command	Deletes the specified file from a ZX Microdrive[note 6][29]
EXP	number	EXTENDED MODE then X	Function	Returns e to the power number[30]
FLASH	number	EXTENDED MODE then SYMBOL SHIFT+V	Command/other	Makes all following text alternate its foreground (INK) and background (PAPER) colours[note 5]
FN	function(value)	EXTENDED MODE then SYMBOL SHIFT+2	Function	Calls the function defined earlier in the program using DEF FN[26]
FORMAT	drive;"name"	EXTENDED MODE then SYMBOL SHIFT+0	Command	Formats the cartridge in the indicated Microdrive and assigns it the identifier name[note 6][31]
FOR	variable = start TO end	F	Command	Starts a FOR-NEXT loop;[32] the variable name may only be one character long[33]
GO SUB	number	H	Command	Makes the program jump to the BASIC line specified by number; when the program encounters the command RETURN, it will jump back to the statement after the GO SUB[34]
GO TO	number	G	Command	Makes the program jump to the BASIC line specified by number
IF	condition THEN	U	Command	Evaluates the condition, and if true, executes the statement that follows the keyword THEN that must come after the condition,[35] for example IF a=1 THEN LET b=2[note 7]
IN	address	EXTENDED MODE then SYMBOL SHIFT+I	Function	Returns a byte read from the hardware input/output port corresponding to the address[36]
INK	number	EXTENDED MODE then SYMBOL SHIFT+X	Command/other	Sets the foreground colour for text and graphics[note 4][note 5][37]
INKEY$		EXTENDED MODE then SYMBOL SHIFT+Z	Function	Returns a string representing the key being pressed on the keyboard at the moment the function is called, or an empty string if none is,[38] but does not wait for a keypress
INPUT	[prompt,] variable	I	Command	Halts program execution until the user types in something on the keyboard and presses the Enter key, then stores the entered value in the specified variable; if the optional prompt is supplied, this will be shown on the screen[39]
INT	number	EXTENDED MODE then R	Function	Returns the integer value of number, rounding down to the nearest whole number[5] (thus, INT -1.1 returns −2, not −1)
INVERSE	number	EXTENDED MODE then SYMBOL SHIFT+M	Command/other	Reverses the colours on all following text if number is 1, so that it uses the current ink colour for the background and the current paper colour for the text, or sets them back to normal if number is 0[note 5][40]
LEN	string	EXTENDED MODE then K	Function	Returns the number of characters (bytes) in string[41]
LET	variable=value	L	Command	Assigns value to the named variable[42]
LINE		EXTENDED MODE then SYMBOL SHIFT+3	Other	When used in an INPUT statement before a string variable, will not put quotation marks ("") around its prompt,[9] for example INPUT "Name: "; LINE n$ When used in a SAVE statement so that when the BASIC program being saved is loaded again, it starts automatically at the line number indicated[43]
LIST	[number]	K	Command	Outputs the current BASIC program to the screen; if the optional number is provided, it omits all lines with a lower number[44]
LLIST	[number]	EXTENDED MODE then SYMBOL SHIFT+V	Command	As LIST except the listing is output to the printer[22]
LN	number	EXTENDED MODE then SYMBOL SHIFT+Z	Function	Returns the natural logarithm of number[45]
LOAD	"[filename]" [CODE [address[, length]]| DATA variable()]	J	Command	Loads a program or data into RAM from tape, ZX Microdrive, disk, etc., deleting any existing BASIC program and variables;[39] if an empty string ("") is provided, this loads the first program found, else it will search the tape for the program named in the string; if the optional CODE is provided, will load the program into memory at the address it had when it was saved, or at the specified address (length is intended as a safety, to try and load the right program in case there are multiple on the tape with the right name but of different lengths);[46] if the optional DATA variable() is provided, will load the data from the tape into the array named variable()[25]
LPRINT	text	EXTENDED MODE then SYMBOL SHIFT+C	Command	As PRINT except output is sent to the printer[22]
MERGE	"[filename]"	EXTENDED MODE then SYMBOL SHIFT+T	Command	As LOAD, except it does not delete the current program and variables; if a line number exists in both, that of the newly loaded program overwrites the existing one. Using MERGE prevents a program saved using LINE from auto-running once loaded[47]
MOVE	stream1 TO stream2	EXTENDED MODE then SYMBOL SHIFT+6	Command	Moves data from one stream (keyboard, screen, file, printer, network, etc.) to another[note 6][48]
NEW		A	Command	Erases the current BASIC program and all variables[39]
NEXT	variable	N	Command	Closes a FOR-NEXT loop; the variable must match that of the corresponding FOR command[49] — "empty" NEXTs to refer to the immediately preceding FOR in the program are not allowed
NOT	condition	SYMBOL SHIFT+S	Logical operator	Returns true if the condition is false, else returns false[note 3][7]
OPEN #	stream	EXTENDED MODE then SYMBOL SHIFT+4	Command	Opens a stream for reading from and/or writing to[note 6][50]
OR		SYMBOL SHIFT+Y	Logical operator	Returns true if either of the conditions on either side of the OR keyword are true, else returns false[note 3][7]
OUT	address, value	EXTENDED MODE then SYMBOL SHIFT+O	Command	Sends the value (a byte) to the hardware [Memory-mapped I/O|input/output port] corresponding to the address[36]
OVER	number	EXTENDED MODE then SYMBOL SHIFT+N	Command/other	Will make following text overprint with an XOR operation what is already on the screen if number is 1, instead of erasing it, or erase it if number is 0[note 5][40]
PAPER	number	EXTENDED MODE then SYMBOL SHIFT+C	Command/other	Sets the background colour for text and graphics[note 4][note 5][37]
PAUSE	delay	M	Command	Halts program execution for the specified delay, in ${\displaystyle {\frac {1}{50))}$ of a second in Europe or ${\displaystyle {\frac {1}{60))}$ in North America[51] (thus, PAUSE 50 halts for one second in Europe)
PEEK	address	EXTENDED MODE then O	Function	Returns a byte representing the contents of the memory location pointed to by address[52]
PI		EXTENDED MODE then M	Function	Returns the value of pi[45]
PLOT	x, y	Q	Command	Draws a pixel in the current INK colour on the screen at the coordinates (x,y)[53]
POINT	(x,y)	EXTENDED MODE then SYMBOL SHIFT+8	Function	Returns 1 if the pixel pointed at graphical coordinates (x,y) is currently in the ink (foreground) colour, else returns 0[17]
POKE	address, value	O	Command	Sets the contents of address in RAM to value[54]
PRINT	[AT x,y;] text	P	Command	Prints text (which must be a string or a number) to the screen;[42] if used with AT, will print at the specified text coordinates, else in the first column of the line after that used by the last PRINT statement[9]
RANDOMIZE	[number]	T	Command	Initializes the random number generator; if used without a number (or with 0), it does this based on the computer's internal clock, else it uses the number supplied, which must be in the range [1,65535][55]
READ	variable	EXTENDED MODE then A	Command	Takes a value from a DATA statement and stores it in the named variable: the first time READ is used, it gets the first value after the first DATA, the second time it gets the next one, and so on[24]
REM	text	E	Command	Begins a comment in the source code, meaning that everything after the REM statement is ignored, until the end of the line[39] — note this includes everything after a colon, which normally begins a new segment: 10 REM Nothing to see here : PRINT "Unprintable" will not produce any output, for example
RESTORE	[number]	EXTENDED MODE then S	Command	Resets where READ commands look for values in DATA statements: if used without a number, the next READ will use the first DATA in the program, with a number it will use the first DATA on or after the line whose number is indicated[56]
RETURN		Y	Command	Returns execution to the first statement following the last GO SUB command that was executed[34]
RND		EXTENDED MODE then T	Function	Returns a pseudo-random number with eight significant figures in the range [0,1)[57]
RUN	[number]	R	Command	Starts the current BASIC program, from its first line if no number is specified, else from the line with that number (or the first one after, if it does not exist)[58]
SAVE	"filename" [DATA variable() | LINE number]	S	Command	Saves the current BASIC program to tape or other storage device, with the filename specified; if the optional LINE followed by a line number is used, then the program will start automatically at the indicated line number when it is LOADed back in; with the optional DATA, the command saves the contents of the array named by the variable instead of the current BASIC program[25]
SCREEN$	[(line, column)]	EXTENDED MODE then SYMBOL SHIFT+	Function/other	As a function, identifies the character at the specified line and column on the screen.[9] Used after the filename in a LOAD or SAVE command, indicates that the contents of the display memory should be loaded or saved; this essentially makes it a shortcut for CODE 16384,6912[note 8] but does not work with VERIFY because the contents of the display memory will be different by the time that command reads back the saved data;[59]
SGN	number	EXTENDED MODE then F	Function	Returns 1 if number is positive, 0 if it is 0, and −1 if it is negative[5]
SIN	number	EXTENDED MODE then Q	Function	Returns the sine of number[23]
STEP	number	SYMBOL SHIFT+D	Other	Indicates the interval used by a FOR statement,[33] for example FOR n=2 TO 6 STEP 2 will skip n=3 and n=5 in the loop
STOP		SYMBOL SHIFT+A	Command	Ends execution of the current program, exiting to the BASIC editor; can also be given when the computer is waiting for input using the INPUT command;[58] once the program is stopped, it can be resumed with CONTINUE
SQR	number	EXTENDED MODE then H	Function	Returns the square root of number[26]
STR$	number	EXTENDED MODE then Y	Function	Returns the character from the computer's character set corresponding to number[60]
TAB	column	EXTENDED MODE then P	Other	In a PRINT statement, makes sure that the text to be output begins in the column specified, wrapping to the next line as necessary, but never more than one line[18]
TAN	number	EXTENDED MODE then E	Function	Returns the tangent of number[61]
THEN	statement	SYMBOL SHIFT+G	Other	Follows the condition in an IF statement to indicate what should happen when the condition evaluates to true[note 7][35]
TO		SYMBOL SHIFT+F	Other	Indicates a range from the number to the left of TO to the number of the right of it, inclusive;[62] when used with FOR both numbers must be supplied, while if used to slice strings, either may be left off to indicate the start or end of the string
USR	string or address	EXTENDED MODE then L	Function	When called with a single-character string, this returns the memory address at which the glyph for the user-defined graphic character corresponding to that character is defined.[12] If called with an address, it starts machine code execution at that address (thus making it one of the few Sinclair BASIC functions to have a Side effect) and returns the contents of the Z80’s BC register pair.[63]
VAL	string	EXTENDED MODE then J	Function	Evaluates the string as a number and returns the result;[64] this can perform calculations: VAL "1+2" returns 3, for example, and also evaluates variables and even other VAL statements: LET a=1: VAL "a+VAL ""2"""[note 9] also returns 3
VAL$	string	EXTENDED MODE then SYMBOL SHIFT+J	Function	Similar to VAL but evaluates the string as a string[5]
VERIFY	"[filename]"	EXTENDED MODE then SYMBOL SHIFT+R	Command	Reads a program or data from tape or other storage, much like LOAD, but instead of loading it into memory, compares it with the program or data that is already in memory. This is intended to be used immediately after a SAVE command, to make sure the program or data has been saved without corruption.[65]

ZX Spectrum

ZX Spectrum+

Keyword entry

In 48K models and older, the keywords are entered via Sinclair's unique keyword entry system, as indicated on the table. The most common commands need one keystroke only; for example, pressing only P at the start of a line on a Spectrum produces the full command PRINT. Less frequent commands require more complex key sequences: BEEP (for example) is keyed by pressing CAPS SHIFT plus SYMBOL SHIFT to access extended mode (later models include an EXTENDED MODE key), keeping SYMBOL SHIFT held down and pressing Z. Keywords are colour-coded on the original Spectrum keyboard to indicate which mode is required:^[66]

• White: key only
• Red on the key itself: SYMBOL SHIFT plus the key
• Green above the key: EXTENDED MODE followed by the key
• Red below the key: EXTENDED MODE followed by SYMBOL SHIFT plus the key

The ZX81 8K BASIC used the shorter forms GOTO, GOSUB, CONT and RAND, whereas the Spectrum 48K BASIC used the longer forms GO TO, GO SUB, CONTINUE and RANDOMIZE. The ZX80 4K BASIC also used these longer forms but differed by using the spelling RANDOMISE. The ZX81 8K BASIC was the only version to use FAST, SCROLL, SLOW and UNPLOT. The ZX80 4K BASIC had the exclusive function TL$(); it was equivalent to the string operator (2 TO ) in later versions.

Unique code points are assigned in the ZX80 character set, ZX81 character set and ZX Spectrum character set for each keyword or multi-character operator, i.e. <=, >=, <>, "" (tokenized on the ZX81 only), ** (replaced with ↑ on the Spectrum). These are expanded by referencing a token table in ROM. Thus, a keyword uses one byte of memory only, a significant saving over traditional letter-by-letter storage. This also meant that the BASIC interpreter could quickly determine any command or function by evaluating one byte, and that the keywords need not be reserved words like in other BASIC dialects or other programming languages, e.g., it is allowed to define a variable named PRINT and output its value with PRINT PRINT. This is also related to the syntax requirement that every line start with a command keyword, and pressing the one keypress for that command at the start of a line changes the editor from command mode to letter mode. Thus, variable assignment requires LET (i.e., LET a=1 not only a=1). This practice is also different from other BASIC dialects. Further, it meant that unlike other BASIC dialects, the interpreter needed no parentheses to identify functions; SIN x was sufficient, no SIN(x) needed (though the latter was allowed). The 4K BASIC ROM of the ZX80 had a short list of exceptions to this: the functions CHR$(), STR$(), TL$(), PEEK(), CODE(), RND(), USR() and ABS() did not have one-byte tokens but were typed in letter-by-letter and required the parentheses. They were listed as the INTEGRAL FUNCTIONS on a label above and to the right of the keyboard.^[67]

128 BASIC, present on ZX Spectrum 128, +2, +3, +2A, and +2B, stored keywords internally in one-byte code points, but used a conventional letter-by-letter BASIC input system. It also introduced two new commands:

• PLAY, which operated the 128k models' General Instrument AY-3-8910 music chip
• SPECTRUM, which switched the 128k Spectrum into a 48k Spectrum compatibility mode

The original Spanish ZX Spectrum 128 included four additional BASIC editor commands in Spanish,^[68][69] one of which was undocumented:

• EDITAR (to edit a line number or invoke the full screen string editor)
• NUMERO (to renumber the program lines)
• BORRAR (to delete program lines)
• ANCHO (to set the column width of the RS-232 device, but undocumented as the code was broken)

Unlike the LEFT$(), MID$() and RIGHT$() functions used in the ubiquitous Microsoft BASIC dialects for home computers, parts of strings in Sinclair BASIC are accessed by numeric range. For example, a$(5 TO 10) gives a substring starting with the 5th and ending with the 10th character of the variable a$. Thus, it is possible to replace the LEFT$() and RIGHT$() commands by simply omitting the left or right array position respectively; for example a$( TO 5) is equivalent to LEFT$(a$,5). Further, a$(5) alone is enough to replace MID$(a$,5,1).

Variable names

Variables holding numeric values may be any length, while string and array variable names must consist of only one alphabetical character. Thus, LET a=5, LET Apples=5, LET a$="Hello", DIM a(10) and DIM a$(10) are all good, while LET Apples$="Fruit", DIM Apples(10) and DIM Apples$(10) are not.

The long variable names allowed for numeric variables can include alphanumeric characters after the first character, so LET a0=5 is allowed but not LET 0a=5. The long variable names can also include spaces, which are ignored, so LET number of apples = 5 is the same as LET numberofapples = 5

Official versions

4K BASIC

• 4K BASIC for ZX80^[70] (so named for residing in 4 KiB read-only memory (ROM)), was developed by John Grant of Nine Tiles for the ZX80. It has integer-only arithmetic.
  • System Commands: NEW RUN LIST LOAD SAVE
  • Control Statements: GOTO IF THEN GOSUB STOP RETURN FOR TO NEXT CONTINUE
  • Input/Output Statements: PRINT INPUT
  • Assignment Statement: LET
  • Other Statements: CLEAR CLS DIM REM RANDOMIZE POKE

8K BASIC

• 8K BASIC is the ZX81 BASIC (also available as an upgrade for the ZX80^[2]), updated with floating-point arithmetic by Steve Vickers, so named for residing in 8 KiB ROM.
  • Statements: PRINT RAND LET CLEAR RUN LIST GOTO CONT INPUT NEW REM PRINT STOP BREAK IF STOP FOR NEXT TO STEP SLOW FAST GOSUB RETURN SAVE LOAD CLS SCROLL PLOT UNPLOT PAUSE LPRINT LLIST COPY DIM POKE NEW
  • Functions: ABS SGN SIN COS TAN ASN ACS ATN LN EXP SQR INT PI RND FUNCTION LEN VALSTR$ NOT CODE CHR$ INKEY$ AT TAB INKEY$ PEEK USR

48 BASIC

• 48 BASIC is the BASIC for the original 16/48 KB RAM ZX Spectrum (and clones), with colour and more peripherals added by Steve Vickers and John Grant. It resides in 16 KB ROM and began to be called 48 BASIC with the introduction of the ZX Spectrum 128 at which time the 16 KB Spectrum was no longer sold and most existing ones in use had been upgraded to 48 KB^[71]

128 BASIC

• 128 BASIC is the BASIC for the ZX Spectrum 128.^[72] It offers extra commands and uses letter-by-letter input.
  • New commands: LOAD ! SAVE ! MERGE ! ERASE PLAY SPECTRUM

+3 BASIC

• +3 BASIC is the BASIC with disk support for the ZX Spectrum +3 and +2A.^[71]
  • New commands: FORMAT COPY

T/S 2000 BASIC

• T/S 2000 BASIC is used on the Spectrum-compatible Timex Sinclair 2068 (T/S 2068) and adds the following six new keywords:
  • DELETE deletes BASIC program line ranges.
  • FREE is a function that gives the amount of free RAM. PRINT FREE will show how much RAM is free.
  • ON ERR is an error-handling function mostly used as ON ERR GO TO or ON ERR CONT.
  • RESET can be used to reset the behaviour of ON ERR. It was also intended to reset peripherals.
  • SOUND controls the AY-3-8192 sound chip.
  • STICK is a function that gives the position of the internal joystick (Timex Sinclair 2090).

BASIC64

• BASIC64 by Timex of Portugal, is a software extension^[73] to allow better Basic programming with the 512×192 and dual display areas graphic modes available only on Timex Sinclair computers. This extension adds commands and does a complete memory remap to avoid the system overwriting the extended screen memory area. Two versions exist due to different memory maps - a version for TC 2048 and a version for T/S 2068 and TC 2068.
  • PRINT # Prints to a specific output channel.
  • LIST # Lists the program to a specific output channel.
  • CLS* Clears both display areas.
  • INK* Sets ink colour for both display areas
  • PAPER* Sets paper colour both display areas
  • SCREEN$ Selects the high / normal resolution modes.
  • PLOT* Plots a pixel and updates the drawing position.
  • LINE Draws a line from the previous PLOT position, supporting arc drawing
  • CIRCLE* Draws a circle or oval, depending on screen mode.

Timex Extended Basic

• Timex Extended Basic by Timex of Portugal is used on the Timex Computer 3256, adding TEC - Timex Extended Commands commands supporting the AY-3-8912 sound chip, RS-232 network and the 512x192 pixel high resolution graphic mode.^[74][75]
  • RAM drive commands: LOAD! SAVE! CAT! MERGE! ERASE! CLEAR!
  • RS-232 commands: FORMAT! LPRINT LLIST
  • AY-3-8912 commands: BEEP!
  • 512x192 resolution commands: SCREEN$ DRAW! PLOT! CIRCLE!

Other versions, extensions, derivatives and successors

Interpreters for the ZX Spectrum family

Several ZX Spectrum interpreters exist.^[76]

• Beta BASIC by Dr. Andy Wright, was originally a BASIC extension, but became a full interpreter.^[77]
• YS MegaBasic by Mike Leaman.^[76][78]
• ZebraOS by Zebra Systems in New York, a cartridge version of T/S 2000 BASIC that used the 512×192 screen mode.^[79]
• Sea Change ROM by Steve Vickers and Ian Logan, modified by Geoff Wearmouth, a replacement ROM with an enhanced Sinclair BASIC.^[80]
• Gosh Wonderful by Geoff Wearmouth, a replacement ROM that fixes bugs and adds a tokenizer, stream lister, delete and renumber commands.^[76][81]
• OpenSE BASIC (formerly SE BASIC) by Andrew Owen, a replacement ROM with bug fixes and many enhancements including ULAplus^[82] support, published as open source in 2011^[83][84][85]

Compilers for the ZX Spectrum family

Several ZX Spectrum compilers exist.^[76]

• HiSoft COLT Compiler (a.k.a. HiSoft COLT Integer Compiler)^[86][87]
• HiSoft BASIC (a.k.a. HiSoft BASIC Compiler), an integer and floating-point capable compiler^[88][89]
• Laser Compiler^[90][91]
• Softek 'IS' Integer Compiler^[92][93] (successor to Softek Integer Compiler^[94])
• Softek 'FP' Full Compiler^[95][96]
• ZIP Compiler^[97][98]

Derivatives and successors for other computers

• SuperBASIC, a much more advanced BASIC dialect introduced with the Sinclair QL personal computer, with some similarities to the earlier Sinclair BASICs^[99]
• SAM Basic, the BASIC on the SAM Coupé, generally considered a ZX Spectrum clone^[100]
• ROMU6 by Cesar and Juan Hernandez - MSX^[76]
• Spectrum 48 by Whitby Computers - Commodore 64^[76]
• Sparky eSinclair BASIC by Richard Kelsh, an operating system loosely based on ZX Spectrum BASIC - Zilog eZ80^[101]
• Sinbas by Pavel Napravnik - DOS^[76]
• Basic^[102] (and CheckBasic^[103]) by Philip Kendall - Unix
• BINSIC^[104] by Adrian McMenamin, a reimplementation in Groovy closely modelled on ZX81 BASIC - Java
• BASin^[105] by Paul Dunn, a complete Sinclair BASIC integrated development environment (IDE) based on a ZX Spectrum emulator^[76] - Windows
• SpecBAS^[106] (a.k.a. SpecOS) by Paul Dunn, an integrated development environment (IDE) providing an enhanced superset of Sinclair BASIC - Windows, Linux, Pandora, and Raspberry Pi
• ZX-Basicus^[107] by Juan-Antonio Fernández-Madrigal, a synthesizer, analyzer, optimizer, interpreter and debugger of Sinclair BASIC 48K for PCs, freely downloadable for Linux and Windows.