working on printing a bit more.

js-assembler/runtime-src/baselib-boxes.js

@@ -43,7 +43,6 @@
     };
 
     Box.prototype.toDomNode = function(params) {
-        params.put(this, true);
         var parent = document.createElement("span");
         parent.appendChild(document.createTextNode('#&'));
         parent.appendChild(params.recur(this.val));

js-assembler/runtime-src/baselib-format.js

@@ -202,13 +202,18 @@
 
     var ToDomNodeParameters = function(params) {
         if (! params) { params = {}; }
-        this.cache = baselib.hashes.makeLowLevelEqHash();
         var k;
         for (k in params) {
             if (params.hasOwnProperty(k)) {
                 this[k] = params[k];
             }
         }
+        if (this.cache === undefined) {
+            this.cache = baselib.hashes.makeLowLevelEqHash();
+        }
+        if (this.cycles === undefined) {
+            this.cycles = baselib.hashes.makeLowLevelEqHash();
+        }
         if (this.depth === undefined) {
             this.depth = 0;
         }
@@ -221,6 +226,8 @@
     ToDomNodeParameters.prototype.incrementDepth = function() {
         return new ToDomNodeParameters({ mode : this.mode,
                                          depth: this.depth + 1,
+                                         cache: this.cache,
+                                         cycles: this.cycles,
                                          objectCounter: this.objectCounter });
     };
     
@@ -241,6 +248,10 @@
         return this.cache.containsKey(x);
     };
 
+    ToDomNodeParameters.prototype.seesOldCycle = function(x) {
+        return this.cycles.containsKey(x);
+    };
+
     ToDomNodeParameters.prototype.get = function(x) {
         return this.cache.get(x);
     };
@@ -249,9 +260,8 @@
         return this.cache.remove(x);
     };
 
-    ToDomNodeParameters.prototype.put = function(x) {
-        this.objectCounter++;
-        return this.cache.put(x, this.objectCounter);
+    ToDomNodeParameters.prototype.put = function(x, v) {
+        return this.cache.put(x, v);
     };
 
     ToDomNodeParameters.prototype.recur = function(x) {
@@ -354,9 +364,23 @@
 
     // toDomNode: scheme-value -> dom-node
     var toDomNode = function(x, params) {
-        var node;
+        var node, retval;
         params = coerseToParams(params);
 
+        if (x === null) {
+            node = document.createElement("span");
+            node.appendChild(document.createTextNode("#<null>"));
+            $(node).addClass("null");
+            return node;
+        }
+
+        if (x === undefined) {
+            node = document.createElement("span");
+            node.appendChild(document.createTextNode("#<undefined>"));
+            $(node).addClass("undefined");
+            return node;
+        }
+
         if (baselib.numbers.isSchemeNumber(x)) {
             node = numberToDomNode(x, params);
             $(node).addClass("number");
@@ -383,20 +407,6 @@
             return node;
         }
 
-        if (x === null) {
-            node = document.createElement("span");
-            node.appendChild(document.createTextNode("#<null>"));
-            $(node).addClass("null");
-            return node;
-        }
-
-        if (x === undefined) {
-            node = document.createElement("span");
-            node.appendChild(document.createTextNode("#<undefined>"));
-            $(node).addClass("undefined");
-            return node;
-        }
-
         if (baselib.functions.isProcedure(x)) {
             node = document.createElement("span");
             node.appendChild(document.createTextNode('#<procedure: ' + x.displayName + '>'));
@@ -410,31 +420,52 @@
             return node;
         }
 
+        if (x.nodeType) {
+            return x;
+        }
+
+
+
         // Otherwise, we know the value is an object.
-        if (params.containsKey(x)) {
+        
+        // If we're along a print path with a loop, we need to stop
+        // and return the key.
+        if (params.seesOldCycle(x)) {
             node = document.createElement("span");
-            node.appendChild(document.createTextNode("#" + params.get(x)));
+            node.appendChild(document.createTextNode("#" + params.cycles.get(x) + "#"));
+            $(node).addClass("cycle");
             return node;
         }
-        var returnVal;
-        if (x.nodeType) {
-            returnVal = x;
-        } else if (x.toDomNode) {
-            returnVal = x.toDomNode(params);
-        } else if (params.getMode() === 'write' && x.toWrittenString) {
+
+        // If we see a fresh cycle, register it.
+        if (params.containsKey(x)) {
+            $('<span/>').text('#' + params.objectCounter +'=')
+                    .prependTo(params.get(x));
+
+            params.cycles.put(x, params.objectCounter);
+            params.objectCounter++;
+
             node = document.createElement("span");
-            node.appendChild(document.createTextNode(x.toWrittenString(params)));
-            returnVal = node;
-        } else if (params.getMode() === 'display' && x.toDisplayedString) {
-            node = document.createElement("span");
-            node.appendChild(document.createTextNode(x.toDisplayedString(params)));
-            returnVal = node;
-        } else {
-            node = document.createElement("span");
-            node.appendChild(document.createTextNode(x.toString()));
-            returnVal = node;
+            node.appendChild(document.createTextNode("#" + params.cycles.get(x) + "#"));
+            $(node).addClass("cycle");
+            return node;
         }
-        return returnVal;
+
+        node = document.createElement("span");
+        params.put(x, node);
+        if (x.toDomNode) {
+            node.appendChild(x.toDomNode(params));
+        } else if (params.getMode() === 'write' && x.toWrittenString) {
+            node.appendChild(document.createTextNode(
+                x.toWrittenString(params)));
+        } else if (params.getMode() === 'display' && x.toDisplayedString) {
+            node.appendChild(document.createTextNode(
+                x.toDisplayedString(params)));
+        } else {
+            node.appendChild(document.createTextNode(x.toString()));
+        }
+        params.remove(x);
+        return node;
     };
 
 

js-assembler/runtime-src/baselib-lists.js

@@ -1,3 +1,4 @@
+/*global $*/
 /*jslint browser: true, unparam: true, vars: true, plusplus: true, maxerr: 50, indent: 4 */
 
 
@@ -7,10 +8,7 @@
     var exports = {};
     baselib.lists = exports;
 
-    
 
-
-    
     var Empty = function () {
     };
     Empty.EMPTY = new Empty();
@@ -48,12 +46,10 @@
         }
     };
 
-    
     // Empty.append: (listof X) -> (listof X)
     Empty.prototype.append = function (b) {
         return b;
     };
-    
 
 
 
@@ -79,7 +75,6 @@
         }
         return ret;
     };
-    
 
     // FIXME: can we reduce the recursion on this?
     Cons.prototype.equals = function (other, aUnionFind) {
@@ -89,9 +84,7 @@
         return (baselib.equality.equals(this.first, other.first, aUnionFind) &&
                 baselib.equality.equals(this.rest, other.rest, aUnionFind));
     };
-    
 
-    
 
     // Cons.append: (listof X) -> (listof X)
     Cons.prototype.append = function (b) {
@@ -104,10 +97,9 @@
             ret = makePair(lst.first, ret);
             lst = lst.rest;
         }
-        
         return ret;
     };
-    
+
 
     Cons.prototype.toWrittenString = function (cache) {
         cache.put(this, true);
@@ -150,26 +142,68 @@
 
 
     Cons.prototype.toDomNode = function (params) {
-        params.put(this, true);
-        var node = document.createElement("span");
-        node.appendChild(document.createTextNode("("));
+        var node;
+
+        var subelts = [], dottedPair = false, i;
         var p = this;
         while (p instanceof Cons) {
-            node.appendChild(params.recur(p.first));
+            subelts.push(params.recur(p.first));
             p = p.rest;
-            if (p !== EMPTY) {
-                node.appendChild(document.createTextNode(" "));
-            }
             if (typeof (p) === 'object' && params.containsKey(p)) {
                 break;
             }
         }
         if (p !== EMPTY) {
-            node.appendChild(document.createTextNode("."));
-            node.appendChild(document.createTextNode(" "));
-            node.appendChild(params.recur(p));
+            dottedPair = true;
+            subelts.push(params.recur(p));
         }
 
+
+        if (params.getMode() === 'constructor') {
+            if (dottedPair) {
+                node = subelts[subelts.length - 1];
+                for (i = subelts.length - 2; i >= 0; i--) {
+                    node = $('<span/>')
+                        .text("(cons ")
+                        .append(subelts[i])
+                        .append(" ")
+                        .append(node)
+                        .append(")").get(0);
+                }
+                return node;
+            } else {
+                node = document.createElement("span");
+                node.appendChild(document.createTextNode("("));
+                node.appendChild(document.createTextElement("list"));
+                node.appendChild(document.createTextElement(" "));
+                node.appendChild(subelts[0]);
+                for (i = 1; i < subelts.length; i++) {
+                    node.appendChild(document.createTextElement(" "));
+                    node.appendChild(subelts[i]);
+                }
+                node.appendChild(document.createTextNode(")"));
+                return node;
+            }
+        }
+
+        node = document.createElement('span');
+        if (params.getMode() === 'print') {
+            node.appendChild(document.createTextNode("'"));
+        }
+        node.appendChild(document.createTextNode("("));
+        node.appendChild(subelts[0]);
+        if (subelts.length > 1) {
+            for (i = 1; i < subelts.length - 1; i++) {
+                node.appendChild(document.createTextNode(" "));
+                node.appendChild(subelts[i]);
+            }
+            if (dottedPair) {
+                node.appendChild(document.createTextNode(" "));
+                node.appendChild(document.createTextNode("."));
+            }
+            node.appendChild(document.createTextNode(" "));
+            node.appendChild(subelts[subelts.length - 1]);
+        }
         node.appendChild(document.createTextNode(")"));
         return node;
     };
@@ -202,7 +236,7 @@
 
     // isList: Any -> Boolean
     // Returns true if x is a list (a chain of pairs terminated by EMPTY).
-    var isList = function (x) { 
+    var isList = function (x) {
         var tortoise, hare;
         tortoise = hare = x;
         if (hare === EMPTY) { return true; }

js-assembler/runtime-src/baselib-structs.js

@@ -33,7 +33,6 @@
 
     Struct.prototype.toDomNode = function (params) {
         var node = document.createElement("span"), i;
-        params.put(this, true);
         $(node).append(document.createTextNode("("));
         $(node).append(document.createTextNode(this._constructorName));
         for(i = 0; i < this._fields.length; i++) {

js-assembler/runtime-src/baselib-vectors.js

@@ -84,7 +84,6 @@
 
     Vector.prototype.toDomNode = function (params) {
         var node = document.createElement("span"), i;
-        params.put(this, true);
         node.appendChild(document.createTextNode("#("));
         for (i = 0; i < this.length(); i++) {
             node.appendChild(params.recur(this.ref(i)));

tests/more-tests/sharing.expected

@@ -24,3 +24,5 @@ jane
 
 true
 false
+#0=(1 . #0#)
+#0=(1 2 . #0#)

tests/more-tests/sharing.rkt

@@ -78,4 +78,16 @@
 (shared ([a (cons 1 a)])
   (begin
     (displayln (pair? a))
-    (displayln (list? a))))
+    (displayln (list? a))))
+
+
+
+
+(shared ([a (cons 1 a)])
+  a)
+
+
+
+(shared ([a (cons 1 b)]
+         [b (cons 2 a)])
+        a)