Description

The aim of this  project is to  implement an interpreter for a  programming  language called AJS (A JavaScript) which is a subset of ECMAScript 2018. The syntax and related descriptions of this language is provided in a separate document.

The  interpreter  is to  be  implemented  in  Racket  with  the  help  of  the  SLLgen scanner  and  parser generator and the Datatype macro extension introduced by D. Friedman and M Wand in their book Essentials of Programming Languages, third edition.

A  file  called  AJS_test_cases.ajs is  provided  with  some  AJS  source  code  for  testing  your interpreter. The test cases are divided into 4 parts:

1.    Simple arithmetic and constant declarations

2.    Function declarations and compound functions

3.    Booleans and conditionals

4.    Recursive functions

In your development, you may choose to first implement the simpler aspects of the language first. For example, you may implement that part of AJS that can only pass the tests in Part 1. Make sure that it works before proceeding to include more syntax to enable your interpreter to pass the tests in Part 2, etc. Marks are allocated to the language features in each of these four parts.

Note that your interpreter does not have to provide the ability to read program code from a file (although it would be nice). But it has to provide a REPL where the users can enter their code.

This project accounts for 50% of the total marks for this course.

Submission

Students can work on their own or form groups of two. In both cases, you will need to self sign-up to a group on Canvas.

Each group is required to submit the following:

1.   Documentation of your implementation including:

.    Verification that the grammar is LL(1)

.    If you are not able to implement the full AJS language as described, then clearly describe  which  part  of  it  is  implemented  and   provide  the  syntax  of  the implemented language

.    Description of additional data structures that you have used to support your implementation

.    Describe   the    approach   and    design   choices   you    have    made   in    your implementation