Inline stack helper implementation

lib/handlebars/compiler/compiler.js

@@ -419,6 +419,7 @@ Handlebars.JavaScriptCompiler = function() {};
       this.stackVars = [];
       this.registers = { list: [] };
       this.compileStack = [];
+      this.inlineStack = [];
 
       this.compileChildren(environment, options);
 
@@ -917,11 +918,20 @@ Handlebars.JavaScriptCompiler = function() {};
       return item;
     },
 
-    pushStack: function(item) {
-      var stack = this.incrStack();
-      this.source.push(stack + " = " + item + ";");
-      this.compileStack.push(stack);
-      return stack;
+    pushStack: function(item, inline) {
+      if (inline) {
+        this.inlineStack.push(item);
+        return item;
+      } else {
+        this.flushInline();
+
+        var stack = this.incrStack();
+        if (item) {
+          this.source.push(stack + " = " + item + ";");
+        }
+        this.compileStack.push(stack);
+        return stack;
+      }
     },
 
     replaceStack: function(callback) {
@@ -937,33 +947,55 @@ Handlebars.JavaScriptCompiler = function() {};
       return stack;
     },
 
-    nextStack: function(skipCompileStack) {
-      var name = this.incrStack();
-      this.compileStack.push(name);
-      return name;
+    nextStack: function() {
+      return this.pushStack();
     },
 
     incrStack: function() {
       this.stackSlot++;
       if(this.stackSlot > this.stackVars.length) { this.stackVars.push("stack" + this.stackSlot); }
+      return this.topStackName();
+    },
+    topStackName: function() {
       return "stack" + this.stackSlot;
     },
+    flushInline: function() {
+      var inlineStack = this.inlineStack;
+      if (inlineStack.length) {
+        this.inlineStack = [];
+        for (var i = 0, len = inlineStack.length; i < len; i++) {
+          var entry = inlineStack[i];
+          if (entry instanceof Literal) {
+            this.compileStack.push(entry);
+          } else {
+            this.pushStack(entry);
+          }
+        }
+      }
+    },
+    isInline: function() {
+      return this.inlineStack.length;
+    },
 
-    popStack: function() {
-      var item = this.compileStack.pop();
+    popStack: function(wrapped) {
+      var inline = this.isInline(),
+          item = (inline ? this.inlineStack : this.compileStack).pop();
 
-      if (item instanceof Literal) {
+      if (!wrapped && (item instanceof Literal)) {
         return item.value;
       } else {
-        this.stackSlot--;
+        if (!inline) {
+          this.stackSlot--;
+        }
         return item;
       }
     },
 
-    topStack: function() {
-      var item = this.compileStack[this.compileStack.length - 1];
+    topStack: function(wrapped) {
+      var stack = (this.isInline() ? this.inlineStack : this.compileStack),
+          item = stack[stack.length - 1];
 
-      if (item instanceof Literal) {
+      if (!wrapped && (item instanceof Literal)) {
         return item.value;
       } else {
         return item;