SuperBASIC

This article is about the interpreter included in Sinclair QDOS. For the unrelated BASIC system by Tymshare, see Tymshare 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 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 is notable for being the first second-generation BASIC to be integrated into a microcomputer's operating system, so making the latter user-extendable.

Advanced Features

• RESPR for resident procedures: e.g. to extend Qdos
• choice of parameters passed to procedures
• procedures return parameters as chosen
• IF - THEN - ELSE - END IF
• FOR - NEXT - EXIT - END FOR
• REPeat - NEXT - EXIT - END REPeat
• SELect ON - ON - REMAINDER - END SELect
• arbitrarily RETurn within procedures & functions
• data type coercion between numeric & string variables
• actual parameters passing data type to formal parameters
• array operations: slicing, joining etc.
• LOCal arrays & (string) variables
• AUTOmatic line numbering
• relative RESTORE & DATA

The example below illustrates the last eight of these features. After entering the statements, entering

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

will print FRI to the screen. Until cleared, 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 a date Stamp "YEARMoDa"
  LET y%=S(1TO 4) : m%=S(5TO 6) : d%=S(7TO 8)

  REM Step 1 - to apply Lachman's Method of 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%

  REMark data statements
  DIM weekdays$(6,3)
  RESTORE 190
  FOR count=0 TO 6 : READ weekdays$(count)

<ctrl><space>

100 DIM month$(12,9)
110 RESTORE 
120 REMark QL User Guide's "Data Read Restore" example ii
130 REMark (appropriately amended relative to example i)
140 FOR count=1 TO 12 : READ month$(count) 
150 DATA "January", "February", "March"
160 DATA "April","May","June"
170 DATA "July","August","September"
180 DATA "October","November","December"
190 DATA "SUN","MON","TUE","WED","THU","FRI","SAT"
199 END DEFine Iso

External link

• The Quantum Leap - to where?: a chapter from Sinclair and the 'Sunrise' Technology