Lisp in JavaScript

JavaScript LISP Interpreter

by Joe Ganley

[Introduction] | [Language Specifications] | [Copy Permissions]

This interpreter for the programming language LISP supports a small portion of the language but sufficient for the purposes of this course.

Functions are described through the use of the DEFINE verb which has the syntax:

(DEFINE <function name> <argument list> <function definition>) **
For example the definition of the cdr of the car of the cdr (cdadr) is:

(define cdadr (e) (cdr (car (cdr e))))
where the identifer cdadr is now to be associated with LAMBDA expression:

(lambda (e) (cdr (car (cdr e))))
Thereafter using cdadr as the first item in a list will result in that LAMBDA expression be invoked.
The other shortcoming is that we can only enter one S-expression at a time in the upper window. Hence the procedure for entering a LISP program is to enter the SET-LAMBDA definitions first, and then to enter the final "main" expression. Provided that the EVALUATE is clicked after each entry, the SET-LAMBDA assignments will be stored for later use. It is strongly recommended that each definition is copied and stored on a note-pad for later re-use or editing.

comphyR2(HP)서버 입니다.
연구목적으로 운영중입니다.
문의사항은 sjkim70@stechstar.com 으로 연락 주십시오.

I wanted to get a feel for just how powerful JavaScript is as a programming language (as opposed to just a scripting language), so I sat down one evening and wrote this. It turns out that it was quite good for this application, since it is so flexible - dynamically sized arrays are used throughout, and associative arrays make the symbol table quite easy.

A fairly complete set of Lisp instructions are implemented (see here). The choice of instructions and some of the implementations of the composite functions were taken from Roger Rohrbach's Lisp in Awk interpreter. The syntax is standard, and only integer arithmetic is available. This is Lisp, not Scheme - scoping is dynamic.

Since this is pretty much a toy, it doesn't do much in the way of error handling. However, it should work on correct Lisp code; if it breaks on code you believe to be correct, please send me mail at janlee.10.ganley@spamgourmet.com.

Permission

The source of this interpreter is copied by permission from Joe Ganley per his copying restrictions.

NOTE: In this version it is not necessary to include the function name and the arguments in a list as in "standard" LISP.

by Joe Ganley

Joe Ganley's Introduction

Permission