North Star BASIC

North Star BASIC was a dialect of the BASIC programming language for the Intel 8080 microprocessor used on the North Star Horizon and available for purchase on other S-100 bus machines of the late 1970s.[1]

One notable difference with other dialects of BASIC of the time was the way in which substrings were addressed using an array-like syntax, a concept sometimes referring to as "slicing". For example, A$(13,17) in North Star BASIC corresponded to MID$(A$,13,5) in other dialects.[2] This string addressing technique is analogous to the one used in Fortran, and was also used in HP Time-Shared BASIC, Atari BASIC and Sinclair BASIC. Strings could be of any length, limited only by available memory, but had to be DIMensioned before use.[3]

While the language was very similar to other BASICs overall, one interesting addition was the addition of an EXIT keyword to pop out of a FOR loop.[4] Different dialects of BASIC handled this in different ways, the equivalent in Integer BASIC and Atari BASIC was POP. FILL could be used to fill a block of memory with a given value.[5]

Most other differences were minor. GOTO was supported, but the alternate form GO TO was not. Computed-gotos, ON X GOTO... did not support GOSUB. INPUT allowed a prompt; INPUT "TYPE IN YOUR AGE",A. INPUT1 worked identically to INPUT, but suppressed the following question-mark.[4] NEW became SCRatch, PEEK became EXAM, and INSTR became MATCH.[6]

The language also added a number of direct-mode commands like BYE to exit BASIC and return to DOS, REN to renumber the lines in the program, and NULL which defined how many nulls to print after pressing return, to use as fill characters.[7]

Some other dialects of BASIC were created that were based on and inspired by North Star BASIC, such as BaZic (a rewrite of North Star BASIC, taking advantage of the faster Zilog Z80 instructions),[1] Megabasic and S.A.I.L.B.O.A.T. (a basic optimized for Z80 and X86 MS-DOS). Some of these were available for other hardware and operating systems, including Unix, CP/M and DOS.

References

Citations
  1. Richard Milewski, "Micro Mike's baZic release 1", InfoWorld, April 27, 1981
  2. Manual 1977, p. 11.
  3. Manual 1977, p. 10.
  4. Manual 1977, p. 8.
  5. Manual 1977, p. 9.
  6. David A. Lien, "The BASIC Handbook" Compusoft Pub., 1981
  7. Manual 1977, p. 5.

Bibliography
  • North Star BASIC version 6 (PDF). North Star Corporation. 1977.
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