[FIX] qweb: handle variable expressions in t-if

closes #390
closes #362

src/qweb/base_directives.ts

@@ -133,7 +133,7 @@ QWeb.addDirective({
   priority: 20,
   atNodeEncounter({ node, ctx }): boolean {
     let cond = ctx.getValue(node.getAttribute("t-if")!);
-    ctx.addIf(`${ctx.formatExpression(cond)}`);
+    ctx.addIf(`${ctx.formatExpression(typeof cond === 'string' ? cond : cond.expr)}`);
     return false;
   },
   finalize({ ctx }) {
@@ -146,7 +146,7 @@ QWeb.addDirective({
   priority: 30,
   atNodeEncounter({ node, ctx }): boolean {
     let cond = ctx.getValue(node.getAttribute("t-elif")!);
-    ctx.addLine(`else if (${ctx.formatExpression(cond)}) {`);
+    ctx.addLine(`else if (${ctx.formatExpression(typeof cond === 'string' ? cond : cond.expr)}) {`);
     ctx.indent();
     return false;
   },

src/qweb/compilation_context.ts

@@ -1,4 +1,4 @@
-import { compileExpr, QWebVar } from "./expression_parser";
+import { compileExpr, QWebVar, QWebExprVar } from "./expression_parser";
 
 export const INTERP_REGEXP = /\{\{.*?\}\}/g;
 //------------------------------------------------------------------------------
@@ -145,7 +145,7 @@ export class CompilationContext {
     this.addLine("}");
   }
 
-  getValue(val: any): any {
+  getValue(val: any): QWebExprVar | string {
     return val in this.variables ? this.getValue(this.variables[val]) : val;
   }
 

src/qweb/qweb.ts

@@ -645,7 +645,7 @@ export class QWeb extends EventBus {
       if (name.startsWith("t-att-")) {
         let attName = name.slice(6);
         const v = ctx.getValue(value);
-        let formattedValue = v.id || ctx.formatExpression(v);
+        let formattedValue = typeof v === 'string' ? ctx.formatExpression(v) : v.id;
 
         if (attName === "class") {
           ctx.rootContext.shouldDefineUtils = true;