[IMP] component: allow dynamic root nodes

closes #283

src/qweb/base_directives.ts

@@ -55,6 +55,7 @@ function compileValueNode(value: any, node: Element, qweb: QWeb, ctx: Context) {
       ctx.rootContext.rootNode = nodeID;
       ctx.rootContext.parentTextNode = nodeID;
       ctx.addLine(`var vn${nodeID} = {text: ${exprID}};`);
+      ctx.addLine(`result = vn${nodeID}`);
     }
   } else {
     let fragID = ctx.generateID();

src/qweb/context.ts

@@ -19,7 +19,7 @@ export class Context {
   shouldDefineParent: boolean = false;
   shouldDefineQWeb: boolean = false;
   shouldDefineUtils: boolean = false;
-  shouldDefineResult: boolean = false;
+  shouldDefineResult: boolean = true;
   shouldProtectContext: boolean = false;
   shouldTrackScope: boolean = false;
   inLoop: boolean = false;
@@ -93,6 +93,9 @@ export class Context {
     if (!this.rootContext.rootNode) {
       this.rootContext.rootNode = node;
     }
+    if (!this.parentNode) {
+        this.addLine(`result = vn${node};`);
+    }
     return this.subContext("parentNode", node);
   }
 

src/qweb/qweb.ts

@@ -333,6 +333,7 @@ export class QWeb extends EventBus {
       ctx.parentNode = parentContext.parentNode!;
       ctx.allowMultipleRoots = true;
       ctx.hasParentWidget = true;
+      ctx.shouldDefineResult = false;
       ctx.addLine(`let c${ctx.parentNode} = extra.parentNode;`);
 
       for (let v in parentContext.variables) {
@@ -405,6 +406,7 @@ export class QWeb extends EventBus {
         // template rendering.
         let nodeID = ctx.generateID();
         ctx.addLine(`var vn${nodeID} = {text: \`${text}\`};`);
+        ctx.addLine(`result = vn${nodeID};`);
         ctx.rootContext.rootNode = nodeID;
         ctx.rootContext.parentTextNode = nodeID;
       }