SuperBASIC

SuperBASIC is an advanced variant of the BASIC programming language with many structured programming additions. It was developed at Sinclair Research by Jan Jones during the early 1980s.

Originally SuperBASIC was intended as the BASIC interpreter for a home computer code-named SuperSpectrum, then under development. This project was later cancelled; however, SuperBASIC was subsequently included in the ROM firmware of the Sinclair QL microcomputer (announced in January 1984), also serving as the command line interpreter for the QL's QDOS operating system.

It was one of the first second-generation BASICs to be integrated into a microcomputer's operating system (unlike BBC BASIC which preceded it in 1981), making the OS user-extendable—as done by Linus Torvalds in his formative years.

Advanced features

 * RESPR for resident procedures, e.g. to extend QDOS
 * choice of parameters passed to procedures
 * procedures return parameters as chosen
 * arbitrarily  from within procedures & functions
 * data type coercion between numeric and string variables
 * actual parameters passing data type to formal parameters
 * array operations: slicing, joining etc.
 * arrays & (string) variables
 * line numbering
 * relative  &
 * array operations: slicing, joining etc.
 * arrays & (string) variables
 * line numbering
 * relative  &

The function below illustrates the last eight of these features. After having  it, entering

PRINT weekdays$(Iso("19631122",1))

will print FRI to the screen. Until cleared (e.g. by entering ), the function Iso will act like an extension to the operating system. Similarly, according to the QL User Guide, "many of the operating system commands are themselves defined as procedures."

Example
AUTO 11,2 DEFine FN Iso(S,O) LOCal y%,m%,d%,i$,n%,w% REM Step 0 - to isolate components of date-stamp S="YEARMoDa" LET y%=S(1TO 4) : m%=S(5TO 6) : d%=S(7TO 8) REM Step 1 - to initiate Lachman's Congruence LET i$=m%*2.56+ 193 : S=S(1TO 6)- 3 REM Step 2 - to compute the day-number within the week LET w%=(S(1TO 2)&"32"DIV 16+ S(1TO 4)DIV 4+ y%+ i$(2TO 3)+ d%)MOD 7 REM Step 3 - to return result SELect ON O                ON O= 5 : n%=i$(2TO 3) ON O= 4 : n%=y% ON O= 3 : n%=m% ON O= 2 : n%=d% ON O= 1 : n%=w% ON O= REMAINDER : n%=-1 END SELect RETurn n%  REM data statements DIM weekdays$(6,3) RESTORE 190 FOR count=0 TO 6 : READ weekdays$(count)