EAGLESIX2734: MetaExpression implementation. We may not want to even port this class.

lib/pipeline/expressions/MetaExpression.js

@@ -19,31 +19,20 @@ klass.parse = function parse(expr, vpsIn) {
 
 //PROTOTYPE MEMBERS
 proto.serialize = function serialize(explain) {
-
+    var doc = {};
+    doc[META] = this.textScore;
+    return doc;
+    //NOTE: Mongo does this: return Value(DOC("$meta" << "textScore"));
 };
 
 proto.evaluateInternal = function evaluateInternal(vars) {
-
+    var doc = vars.getRoot();
+    return root.hasTextScore() ? root.getTextScore : undefined;
 };
 
 proto.addDependencies = function addDependencies(deps, path) {
-
+    deps.needTextScore = true;
 };
 
 /** Register Expression */
-Expression.registerExpression(klass.opName, base.parse(klass));
-
-    Value ExpressionMeta::serialize(bool explain) const {
-        return Value(DOC("$meta" << "textScore"));
-    }
-
-    Value ExpressionMeta::evaluateInternal(Variables* vars) const {
-        const Document& root = vars->getRoot();
-        return root.hasTextScore()
-                ? Value(root.getTextScore())
-                : Value();
-    }
-
-    void ExpressionMeta::addDependencies(DepsTracker* deps, vector<string>* path) const {
-        deps->needTextScore = true;
-    }
+Expression.registerExpression(klass.opName, base.parse(klass));