a2int

Apple II INTEGER BASIC

Keywords

In all-caps letters like some purists require, this was the original 1976 BASIC for the Apple I and Apple II computers, written by Stephen Wozniak himself. This name, however, only became used later, to differentiate it from the newer Applesoft floating-point BASIC.

Wozniak's admitted main goal was to have a BASIC which himself and his Homebrew Computer Club friends could use for writing games. Integer maths was enough and fast for that purpose. Floating-point support was however a major desire expressed by users and Woz even wrote a library for that, but had to turn his attention to Apple's Disk-II while Steve Jobs licensed the 6502-processor port of BASIC-80 from Microsoft.

Where it is/was used

  • Apple I, loaded from cassette tape (USA, 1976)
  • Apple II, from ROM (USA, 1978)

Noteworthy characteristics

Apart from being able to perform only 16-bit integer mathematics, INTEGER BASIC had its share of peculiarities.

  • Strings were implemented and manipulated like character arrays, as done by HP Time-Shared BASIC and later Atari BASIC. Likewise, arrays of strings were not supported. Array variables had to be DIMensioned before used and substrings were obtained from a 0-based index, like in PRINT S$(0,3) for the first 4 characters of S$.
  • Just like ATARI BASIC as well, INTEGER BASIC imposed no limits on size for variables names, but they could not contain any language keyword.
  • Program line size was limited to 128 characters.
  • It implemented ASC, but not its counterpart CHR$.
  • The device slots so important for the Apple I/Apple II were accessed by input or output redirection with, respectively, IN and PR. From the moment they were used, commands like INPUT and PRINT would operate on the chosen device. PR#0 and IN#0 would bring I/O back to the console.
  • TAB and VTAB were implemented as statements and did not require parenthesis around their arguments, as opposed to Microsoft BASICs.
  • FOR…NEXT loops could be interrupted with the POP statement.

Environment and usage

INTEGER BASIC was an interpreter with a REPL (Read, Eval, Print, Loop) interface just as almost every microcomputer of its era. It had a > sign as its prompt, which differentiated it from Applesoft with its ] prompt.

Extensions

Curiosities

Apple BASIC has a peculiar command that is not listed up there and we'd better not create a page for. CON was replaced by CONT in Applesoft and most BASICs, and works pretty much the same way. Problem is that CON is one of the forbidden file names on Windows, even with an extension, and pages of this site are maintained mostly on Windows machines. This is something traced back to CP/M that Microsoft still maintains alive as of 2023 on Windows 10. Dude…

Influenced by

  • HP Time-Shared BASIC - No surprise here: Woz had been an HP employee and used HP BASIC's manual as his reference for writing INTEGER BASIC. Its more noticeable influence is the array-based string implementation and usage, similar to the one found in Atari BASIC.

Influence for

Versions and successors

References

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