Acornsoft LISP
Encyclopedia
Acornsoft LISP is a dialect and commercial implementation of the Lisp programming language, released in the early 1980s for the 8-bit BBC Micro
BBC Micro
The BBC Microcomputer System, or BBC Micro, was a series of microcomputers and associated peripherals designed and built by Acorn Computers for the BBC Computer Literacy Project, operated by the British Broadcasting Corporation...

 and Acorn Electron
Acorn Electron
The Acorn Electron is a budget version of the BBC Micro educational/home computer made by Acorn Computers Ltd. It has 32 kilobytes of RAM, and its ROM includes BBC BASIC along with its operating system....

 computers.

Description

Acornsoft LISP was released on cassette, disk and ROM cartridge. The ROM cartridge version has instantaneous loading as well as a greater amount of available free RAM for user definitions.

In contrast with large-scale LISP implementations, Acornsoft's variant only has a modest number of built-in definitions as it has to fit in the limited memory space of the 8-bit Acorn computers.

The interpreter is implemented in 6502
MOS Technology 6502
The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle and Bill Mensch for MOS Technology in 1975. When it was introduced, it was the least expensive full-featured microprocessor on the market by a considerable margin, costing less than one-sixth the price of...

machine-code and is 5.5K in size. The supplied LISP workspace image containing commonly used built-in functions and constants is 3K in size, although this can be deleted if not needed by the user to free up more memory.

Supported datatypes include nested lists, 16-bit signed integers and strings up to 127 characters in length. LOOP, WHILE and UNTIL keywords are available for program control.

The book LISP on the BBC Microcomputer by the Acornsoft LISP developers, Gillian Cattell and Arthur Norman was sold separately from the software and contains examples illustrating use of the Acornsoft specific features such as the VDU function allowing for machine-specific graphics capabilities. The book also contains working examples including a tree-sorting program, an arbitrary arithmetic package, an animal guessing game, a route finding program, a graphics package, a simple compiler and an adventure game.

Demonstration image

A route-finding demo program was supplied as standard with the interpreter. The program can be loaded with the command (LOAD 'ROUTE-M) and tested by typing (ROUTE-M 'OXFORD 'CAMBRIDGE) which for example will display the output (85 CAMBRIDGE BEDFORD WATFORD OXFORD) thus showing the total mileage of the shortest possible route and listing intermediate towns visited.

External links

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