diff --git a/javascript/gflib.js b/javascript/gflib.js
index fb8016ab..a570bbb3 100644
--- a/javascript/gflib.js
+++ b/javascript/gflib.js
@@ -5,7 +5,7 @@ function Fun(name) {
 }
 Fun.prototype.print = function () { return this.show(0); } ;
 Fun.prototype.show = function (prec) {
-	if (this.name == '?') {
+	if (this.isMeta()) {
 		if (isUndefined(this.type)) {
 			return '?';
 		} else {
@@ -44,7 +44,22 @@ Fun.prototype.getChildren = function () {
 	}
 	return a;
 } ;
-
+Fun.prototype.isMeta = function() {
+	return this.name == '?';
+} ;
+Fun.prototype.isComplete = function() {
+	if (this.isMeta()) {
+		return false;
+	} else {
+		var cs = this.getChildren();
+		for (var i in cs) {
+			if (!cs[i].isComplete()) {
+				return false;
+			}
+		}
+		return true;
+	}
+} ;
 
 /* Concrete syntax terms */
 
@@ -103,17 +118,13 @@ Abstract.prototype.copyTree = function(x, type) {
 	return this.annotate(this.copyTree_(x), type);
 };
 Abstract.prototype.copyTree_ = function(x) {
-	if (typeof x == 'string' && x == '?') {
-		return new Fun('?');
-	} else {
-		var t = new Fun(x.name);
-		for (var i = 0; ; i++) {
-			var c = x['arg' + i];
-			if (isUndefined(c)) { break; }
-			t.setChild(i, this.copyTree(c));
-		}
-		return t;
+	var t = new Fun(x.name);
+	for (var i = 0; ; i++) {
+		var c = x['arg' + i];
+		if (isUndefined(c)) { break; }
+		t.setChild(i, this.copyTree(c));
 	}
+	return t;
 } ;
 Abstract.prototype.parseTree = function(str, type) { 
 	return this.annotate(this.parseTree_(str.match(/[\w\']+|\(|\)|\?/g), 0), type); 
@@ -155,7 +166,7 @@ Concrete.prototype.addRule = function (name, f) { this.rules[name] = f; };
 Concrete.prototype.lindef = function (cat, v) { return this.rules["_d"+cat]([new Str(v)]); } ;
 Concrete.prototype.linearize = function (tree) { return this.linearizeToTerm(tree).print(); };
 Concrete.prototype.linearizeToTerm = function (tree) {
-	if (tree.name == '?') {
+	if (tree.isMeta()) {
 		if (isUndefined(tree.type)) {
 			return new Meta();
 		} else {