introduce template method for closure return value handling. Now obje…

…ct closures must implement the method do instead of process

README.md

@@ -124,7 +124,7 @@ or
 
 ```javascript
 class CalculateTotalPrize extends Closure {
-	process(fact, context) {
+	do(fact, context) {
 		fact.totalPrice = fact.books.reduce((total, book) => total + book.price, 0);
 		return fact;
 	} 
@@ -193,7 +193,7 @@ function (fact, context) {
 
 //the same thing implemented through a class
 class TaxCalculator extends Closure {
-	process(fact, context) {
+	do(fact, context) {
 		return fact.totalPrice * context.parameters.salesTax;
 	}
 }

lib/closure/Closure.js

@@ -29,6 +29,21 @@ class Closure {
 	 * @return {Promise} a promise that will be resolved to some result
 	 */
 	process(fact, context) {
+		const result = this.do(fact, context);
+		return Promise.resolve(result);
+	}
+
+	/**
+	 * Evaluates the closure against a certain fact
+	 *
+	 * @param {Object} fact								a fact
+	 * @param {Context} context						an execution context.
+	 * @param {Object} context.parameters the execution parameters, if any
+	 * @param {Engine} context.engine			the rules engine
+	 *
+	 * @return {Object} the result of the evaluation
+	 */
+	do(fact, context) {
 		throw new Error("This is an abstract closure, how did you get to instantiate this?");
 	}
 

lib/closure/ClosureReducer.js

@@ -18,7 +18,7 @@ class ClosureReducer extends Closure {
 		this.closures = closures || util.raise(`Cannot build closure reducer [${name}] without closure chain`);
 	}
 
-	* process(fact, context) {
+	* do(fact, context) {
 		for (let closure of this.closures) {
 			fact = yield closure.process(fact, context);
 		}

lib/closure/FunctionalClosure.js

@@ -31,9 +31,8 @@ class FunctionalClosure extends Closure {
 	 *
 	 * @return {Promise} a promise that will be resolved to some result
 	 */
-	process(fact, context) {
-		const result = this.fn.call(this, fact, context);
-		return Promise.resolve(result);
+	do(fact, context) {
+		return this.fn.call(this, fact, context);
 	}
 
 }

lib/closure/Rule.js

@@ -28,7 +28,7 @@ class Rule extends Closure{
 	 * @return {Promise} a promise that will be resolved to some result (typically
 	 *                   such result will be used as next's rule fact)
 	 */
-	* process(fact, context) {
+	* do(fact, context) {
 		const matches = yield this.evaluateCondition(fact, context);
 		if (matches) {
 			context.ruleFired(this);

lib/closure/RuleFlow.js

@@ -5,7 +5,7 @@ const wrap = require("async-class-co").wrap,
 
 class RuleFlow extends ClosureReducer {
 
-	* process(fact, context) {
+	* do(fact, context) {
 		context.initiateFlow();
 		fact = yield super.process(fact, context);
 		context.endFlow();

package.json

@@ -1,6 +1,6 @@
 {
   "name": "rules-js",
-  "version": "0.0.3",
+  "version": "0.0.4",
   "description": "A simple rule-engine for javascript",
   "main": "index.js",
   "author": "Claudio Fernandez <[email protected]>",