diff --git a/index.js b/index.js
index c934992..32c84bc 100644
--- a/index.js
+++ b/index.js
@@ -4,12 +4,12 @@ module.exports = function (ast, vars) {
     if (!vars) vars = {};
     var FAIL = {};
     
-    var result = (function walk (node, scopeVars) {
+    var result = (function walk (node, noExecute) {
         if (node.type === 'Literal') {
             return node.value;
         }
         else if (node.type === 'UnaryExpression'){
-            var val = walk(node.argument)
+            var val = walk(node.argument, noExecute)
             if (node.operator === '+') return +val
             if (node.operator === '-') return -val
             if (node.operator === '~') return ~val
@@ -19,7 +19,7 @@ module.exports = function (ast, vars) {
         else if (node.type === 'ArrayExpression') {
             var xs = [];
             for (var i = 0, l = node.elements.length; i < l; i++) {
-                var x = walk(node.elements[i]);
+                var x = walk(node.elements[i], noExecute);
                 if (x === FAIL) return FAIL;
                 xs.push(x);
             }
@@ -31,7 +31,7 @@ module.exports = function (ast, vars) {
                 var prop = node.properties[i];
                 var value = prop.value === null
                     ? prop.value
-                    : walk(prop.value)
+                    : walk(prop.value, noExecute)
                 ;
                 if (value === FAIL) return FAIL;
                 obj[prop.key.value || prop.key.name] = value;
@@ -59,9 +59,9 @@ module.exports = function (ast, vars) {
                 return r;
             }
 
-            var l = walk(node.left);
+            var l = walk(node.left, noExecute);
             if (l === FAIL) return FAIL;
-            var r = walk(node.right);
+            var r = walk(node.right, noExecute);
             if (r === FAIL) return FAIL;
             
             if (op === '==') return l == r;
@@ -96,23 +96,29 @@ module.exports = function (ast, vars) {
             else return FAIL;
         }
         else if (node.type === 'CallExpression') {
-            var callee = walk(node.callee);
+            var callee = walk(node.callee, noExecute);
             if (callee === FAIL) return FAIL;
             if (typeof callee !== 'function') return FAIL;
+
             
-            var ctx = node.callee.object ? walk(node.callee.object) : FAIL;
+            var ctx = node.callee.object ? walk(node.callee.object, noExecute) : FAIL;
             if (ctx === FAIL) ctx = null;
 
             var args = [];
             for (var i = 0, l = node.arguments.length; i < l; i++) {
-                var x = walk(node.arguments[i]);
+                var x = walk(node.arguments[i], noExecute);
                 if (x === FAIL) return FAIL;
                 args.push(x);
             }
+
+            if (noExecute) {
+                return undefined;
+            }
+
             return callee.apply(ctx, args);
         }
         else if (node.type === 'MemberExpression') {
-            var obj = walk(node.object);
+            var obj = walk(node.object, noExecute);
             // do not allow access to methods on Function 
             if((obj === FAIL) || (typeof obj == 'function')){
                 return FAIL;
@@ -121,26 +127,25 @@ module.exports = function (ast, vars) {
                 if (isUnsafeProperty(node.property.name)) return FAIL;
                 return obj[node.property.name];
             }
-            var prop = walk(node.property);
+            var prop = walk(node.property, noExecute);
             if (prop === null || prop === FAIL) return FAIL;
             if (isUnsafeProperty(prop)) return FAIL;
             return obj[prop];
         }
         else if (node.type === 'ConditionalExpression') {
-            var val = walk(node.test)
+            var val = walk(node.test, noExecute)
             if (val === FAIL) return FAIL;
-            return val ? walk(node.consequent) : walk(node.alternate)
+            return val ? walk(node.consequent) : walk(node.alternate, noExecute)
         }
         else if (node.type === 'ExpressionStatement') {
-            var val = walk(node.expression)
+            var val = walk(node.expression, noExecute)
             if (val === FAIL) return FAIL;
             return val;
         }
         else if (node.type === 'ReturnStatement') {
-            return walk(node.argument)
+            return walk(node.argument, noExecute)
         }
         else if (node.type === 'FunctionExpression') {
-            
             var bodies = node.body.body;
             
             // Create a "scope" for our arguments
@@ -157,7 +162,7 @@ module.exports = function (ast, vars) {
                 else return FAIL;
             }
             for(var i in bodies){
-                if(walk(bodies[i]) === FAIL){
+                if(walk(bodies[i], true) === FAIL){
                     return FAIL;
                 }
             }
@@ -173,14 +178,14 @@ module.exports = function (ast, vars) {
         else if (node.type === 'TemplateLiteral') {
             var str = '';
             for (var i = 0; i < node.expressions.length; i++) {
-                str += walk(node.quasis[i]);
-                str += walk(node.expressions[i]);
+                str += walk(node.quasis[i], noExecute);
+                str += walk(node.expressions[i], noExecute);
             }
-            str += walk(node.quasis[i]);
+            str += walk(node.quasis[i], noExecute);
             return str;
         }
         else if (node.type === 'TaggedTemplateExpression') {
-            var tag = walk(node.tag);
+            var tag = walk(node.tag, noExecute);
             var quasi = node.quasi;
             var strings = quasi.quasis.map(walk);
             var values = quasi.expressions.map(walk);
diff --git a/test/eval.js b/test/eval.js
index 87cb6d9..ed5cf90 100644
--- a/test/eval.js
+++ b/test/eval.js
@@ -44,6 +44,20 @@ test('array methods', function(t) {
     t.deepEqual(evaluate(ast), [2, 4, 6]);
 });
 
+test('array methods invocation count', function(t) {
+    t.plan(2);
+
+    var variables = {
+        values: [1, 2, 3],
+        receiver: []
+    };
+    var src = 'values.forEach(function(x) { receiver.push(x); })'
+    var ast = parse(src).body[0].expression;
+    evaluate(ast, variables);
+    t.equal(variables.receiver.length, 3);
+    t.deepEqual(variables.receiver, [1, 2, 3]);
+})
+
 test('array methods with vars', function(t) {
     t.plan(1);
 
@@ -146,4 +160,18 @@ test('short circuit evaluation OR', function(t) {
     var ast = parse(src).body[0].expression;
     evaluate(ast, variables);
     t.equals(fnInvoked, false);
-})
\ No newline at end of file
+})
+
+test('function declaration does not invoke CallExpressions', function(t) {
+    t.plan(1);
+
+    var invoked = false;
+    var variables = {
+        noop: function(){},
+        onInvoke: function() {invoked = true}
+    };
+    var src = 'noop(function(){ onInvoke(); })';
+    var ast = parse(src).body[0].expression;
+    evaluate(ast, variables);
+    t.equal(invoked, false);
+});
\ No newline at end of file