First output from the chitchat compiler (after the new grammar overhaul)

OrderedSet.js

// Chitchat Source
// -----------------
// 
// ;;; OrderedSet
// ;;; ----------
// ;;;
// ;;; A Collection class that wraps an Array.
// ;;; It maintains immutability, an order, and
// ;;; does not contain duplicates
// ;;; 
// ;;; Items of the Ordered Set should implement 'Ord'
// (class OrderedSet
//     (constructor (items, ordered, distinct)
//         (set! this.items (or items #[]))
// 
//         ;; ensure the qualities of the ordered set in this.items
//         ;; call uniquify! unless the items are known to be distinct
//         ;; call sort! unless the items are known to be sorted
//         (if distinct.isFalse? (this uniquify!)
//             ordered.isFalse?  (this sort!)))
// 
//     (method (contains? needle)
//         (this.items contains? needle))
// 
//     (method (asArray)
//         ;; return a clone so that clients don't
//         ;; mutate our internal array
//         this.items.cloneArray)
// 
//     (method (slice a b)
//         (this.items slice a, b))
// 
//     (method (nth i)
//         this.items.[i])
// 
//     (method (length)
//         this.items.length)
// 
//     (method (concat ls)
//         (let [;; ls can be an OrderedSet or an Array
//               (items  (if (ls isAn OrderedSet) ls.items
//                           (ls isAn Array) ls))
// 
//               ;; items that don't exist in the destination
//               (new-items (ls filter ^(this contains #0) this))]
// 
//             ;; return the same OrderedSet unless there are new items
//             (if new-items.isEmpty?
//               this
//               (OrderedSet new (this.items concat new-items) true))))
// 
//     (method (sort!)
//         ;; Ensure that this.items is sorted by the Ord generics
//         (this.items sort ^(if (#0 > #1) MORE
//                               (#1 < #0) LESS
//                               EQUAL)))
// 
//     (method (uniqify!)
//         ;; Ensure that this.items is distinct
//         (set! this.items
//             (this.items reduce ^[out, item] (if (out contains? item)
//                                                 out
//                                                 (out concat item))
//                                 #[]))))
// 
// -----------------
// Javascript Output
// -----------------
var _passMessage = require("chitchat").passMessage;
OrderedSet = function(ordered, distinct) {
    this.items = _passMessage(or, "items", [ [] ]);
    _passMessage(distinct, "isFalse?") ? _passMessage(this, "uniquify!") : _passMessage(ordered, "isFalse?") ? _passMessage(this, "sort!") : null;
};

OrderedSet.prototype["contains?"] = function(needle) {
    return _passMessage(_passMessage(this, "items"), "contains?", [ needle ]);
};

OrderedSet.prototype.asArray = function() {
    return _passMessage(_passMessage(this, "items"), "cloneArray");
};

OrderedSet.prototype.slice = function(a, b) {
    return _passMessage(_passMessage(this, "items"), "slice", [ a, b ]);
};

OrderedSet.prototype.nth = function(i) {
    return _passMessage(_passMessage(this, "items"), i);
};

OrderedSet.prototype.length = function() {
    return _passMessage(_passMessage(this, "items"), "length");
};

OrderedSet.prototype.concat = function(ls) {
    return function() {
        var items = _passMessage(ls, "isAn", [ OrderedSet ]) ? _passMessage(ls, "items") : _passMessage(ls, "isAn", [ Array ]) ? ls : null, new_minus_items = _passMessage(ls, "filter", [ function() {
            return _passMessage(this, "contains", [ arguments[0] ]);
        }, this ]);
        return _passMessage(new_minus_items, "isEmpty?") ? this : _passMessage(OrderedSet, "new", [ _passMessage(_passMessage(this, "items"), "concat", [ new_minus_items ]), !0 ]);
    }.call(this, typeof arguments != "undefined" ? arguments : []);
};

OrderedSet.prototype["sort!"] = function() {
    return _passMessage(_passMessage(this, "items"), "sort", [ function() {
        return _passMessage(arguments[0], ">", [ arguments[1] ]) ? MORE : _passMessage(arguments[1], "<", [ arguments[0] ]) ? LESS : EQUAL;
    } ]);
};

OrderedSet.prototype["uniqify!"] = function() {
    return this.items = _passMessage(_passMessage(this, "items"), "reduce", [ function(out, item) {
        return _passMessage(out, "contains?", [ item ]) ? out : _passMessage(out, "concat", [ item ]);
    }, [] ]);
};