lisp16#

Simple cross platform 16bit Lisp interpreter.

About#

This project is intended as case study of Lisp implementation with following features:

  • cross platform compatibility

    • support for 8bit/16bit architectures (microcontrollers)

    • possibility of running on POSIX systems

    • small platform compatibility layer

  • reduced Lisp dialect mostly based on Scheme

    • LISP-1 namespace

    • tail call optimization

    • macros

  • tree walking interpreter

    • possibility of multiple independent interpreter instances as part of single process

    • simple mark and sweep garbage collection

    • API design taking into account possibility of usage with foreign function interface

  • intended for educational/testing purposes

    • emphasis on source code functionality organization over binary size or lines of code (or other kinds of optimization)

    • accompanied documentation with implementation explanation

Following features are considered out of scope for this project:

  • real-life production usage

  • execution speed optimization

  • virtual machine or machine code compilation

  • rich standard library

Building and usage#

8bit AVR microcontrollers#

Build targeting 8bit AVR microcontrollers (tested with ATmega328P) depends on avr-gcc and associated binutils.

Shell script:

$ ./build-avr8.sh

produces build/avr8/lisp16.bin binary that can be written to microcontroller’s flash.

After writing binary to flash, microcontroller will execute lisp16 repl with UART used as input/output port.

POSIX system#

Build targeting POSIX systems depends on C compiler (gcc with musl C library is used by default) and implementation of getchar/putchar and malloc/free functions (malloc can be replaced with static allocation in case multiple interpreter instances are not needed).

Shell script:

$ ./build-posix.sh

produces build/posix/lisp16 static binary.

Execution of build/posix/lisp16 starts lisp16 repl stdin/stdout used as input/output port.

Documentation#

Building of documentation depends on python with sphinx and furo modules available.

Shell script:

$ ./build-docs.sh

produces build/docs folder containing documentation.

License#

lisp16 - simple cross platform 16bit Lisp interpreter

Copyright (C) 2022 Bozo Kopic

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.

Content#