SLang versions
==============

V 1.0
===== 

+ applied lambda calculus with numbers and primitive operations +, *, add1

Interpreter versions:
     1.01 Initial proof of concept
     1.02 Changes the front end: the grammar is now in a pop-up window
                                 and button to hide/show the test cases
     1.03 Changed internal data structures from objects to arrays 
     1.04 removed all jshint errors by making absyn.js and env.js into
          modules and many small adjustments
          [Spring 2015] This is the version called SLang 1 that was 
          described In slide sets number 17 through 20 and that was the 
          starting point for A5.
     1.05 version 1.04 plus changes to the language described on slide 20-2
     1.06 version 1.04 plus the solution to Assignment 5
           TN removed this in 2018 to keep students from accessing solution.
           Contact him if you want it
     1.07 version 1.04 plus let block

V 2.0
===== 

+ SLang 1.07 plus non-functional features

     2.00 references in the environment, set expression, print expression, 
          let exp with block expression
     2.01 version 2.00 + solution to assignment 6
           TN removed this in 2018 to keep students from accessing solution.
           Contact him if you want it

V 3.0
===== 

+ SLang 2.00 plus OO features

     3.00 classes, objects, new, method calls, this
          as described in class
     3.01 add super calls (for assignment 7)