Added optional node (?nodename) and node renaming (newName:oldName)

src/Nodes/OptionalNode.js

@@ -0,0 +1,28 @@
+/**
+ * Created by iddo on 7/13/17.
+ */
+"use strict";
+
+class OptionalNode {
+    constructor(innerNode) {
+        this.innerNode = innerNode;
+    }
+
+    getName() {
+        return this.innerNode.getName();
+    }
+
+    eval(context) {
+        return new Promise((resolve, reject) => {
+            this.innerNode.eval(context)
+                .then((val) => {
+                    resolve(val);
+                })
+                .catch((err) => {
+                    resolve(null);
+                });
+        });
+    }
+}
+
+module.exports = OptionalNode;

src/Nodes/RenameNode.js

@@ -0,0 +1,21 @@
+/**
+ * Created by iddo on 7/13/17.
+ */
+"use strict";
+
+class RenameNode {
+    constructor(name, innerNode) {
+        this.name = name;
+        this.innerNode = innerNode;
+    }
+
+    getName() {
+        return this.name;
+    }
+
+    eval(context) {
+        return this.innerNode.eval(context);
+    }
+}
+
+module.exports = RenameNode;

src/Parser/grammer-raw.pegjs

@@ -12,18 +12,18 @@ Complex = "{" firstNode:Node? nodes:("," Node)* "}" {
 }
 
 Node
-	= FunctionNode
+	= RenameNode
+    / OptionalNode
+    / FunctionNode
     / CompositeNode
 	/ LeafNode
 
-LeafNode = Word
-
-CompositeNode = label:Word values:Complex {
-    return {'label' : label, 'value': values};
+RenameNode = name:Word ":" n:Node {
+	return {type: 'rename', value:n, name:name}
 }
 
-FunctionNode = label:Word args:ArgSet values:Complex {
-	return {'label': label, 'args': args, 'value': values};
+OptionalNode = "?" n:Node {
+	return {type: 'optional', value:n}
 }
 
 ArgSet = "(" tuple:KVTuple? tuples:("," KVTuple)* ")" {
@@ -61,6 +61,6 @@ Word = chars:[-<*=>@_0-9"'a-zA-Z.]+ {
 	return chars.join("");
 }
 
-ValueWord = '"' chars:[-<*=>,{}@_0-9\/:a-zA-Z.]+ '"' {
+ValueWord = '"' chars:[-<*=>,{}@_0-9\?/:a-zA-Z.]+ '"' {
 	return '"' + chars.join("") + '"';
 }