From 232ff7bff340d6a12dce8ec70d9b491a2b8c9fdb Mon Sep 17 00:00:00 2001
From: Michael Donaldson <mike@mike-donaldson.com>
Date: Mon, 27 Feb 2017 10:18:01 +0000
Subject: [PATCH 1/2] Refactor mount syntax

---
 packages/ember-glimmer/lib/syntax/mount.js | 70 +++++++++++++++++-----
 1 file changed, 54 insertions(+), 16 deletions(-)

diff --git a/packages/ember-glimmer/lib/syntax/mount.js b/packages/ember-glimmer/lib/syntax/mount.js
index 0570e85567e..bc6b1a270fb 100644
--- a/packages/ember-glimmer/lib/syntax/mount.js
+++ b/packages/ember-glimmer/lib/syntax/mount.js
@@ -13,6 +13,14 @@ import { OutletLayoutCompiler } from './outlet';
 import { FACTORY_FOR } from 'container';
 import AbstractManager from './abstract-manager';
 
+function dynamicEngineFor(vm, symbolTable) {
+  let env     = vm.env;
+  let args    = vm.getArgs();
+  let nameRef = args.positional.at(0);
+
+  return new DynamicEngineReference({ nameRef, env, symbolTable });
+}
+
 /**
   The `{{mount}}` helper lets you embed a routeless engine in a template.
   Mounting an engine will cause an instance to be booted and its `application`
@@ -39,45 +47,75 @@ export function mountMacro(path, params, hash, builder) {
     params.length === 1 && hash === null
   );
 
-  let name = params[0];
-
   assert(
     'The first argument of {{mount}} must be quoted, e.g. {{mount "chat-engine"}}.',
-    typeof name === 'string'
-  );
-
-  assert(
-    `You used \`{{mount '${name}'}}\`, but the engine '${name}' can not be found.`,
-    builder.env.owner.hasRegistration(`engine:${name}`)
+    typeof params[0] === 'string'
   );
 
-  builder.component.static(new MountDefinition(name, builder.env), [params, hash, null, null], builder.symbolTable);
+  let definitionArgs = [params.slice(0, 1), null, null, null];
+  let args = [null, null, null, null];
+  builder.component.dynamic(definitionArgs, dynamicEngineFor, args, builder.symbolTable);
   return true;
 }
 
+class DynamicEngineReference {
+  constructor({ nameRef, env, symbolTable, args }) {
+    this.tag = nameRef.tag;
+    this.nameRef = nameRef;
+    this.env = env;
+    this.symbolTable = symbolTable;
+    this.args = args;
+    this._lastName = undefined;
+    this._lastDef = undefined;
+  }
+
+  value() {
+    let { env, nameRef, /*symbolTable*/ } = this;
+    let nameOrDef = nameRef.value();
+
+    if (this._lastName === nameOrDef) {
+      return this._lastDef;
+    }
+
+    assert(
+      `You used \`{{mount '${nameOrDef}'}}\`, but the engine '${nameOrDef}' can not be found.`,
+      env.owner.hasRegistration(`engine:${nameOrDef}`)
+    );
+
+    if (!env.owner.hasRegistration(`engine:${nameOrDef}`)) {
+      return null;
+    }
+
+    this._lastName = nameOrDef;
+    this._lastDef = new MountDefinition(nameOrDef, env);
+
+    return this._lastDef;
+  }
+}
+
 class MountManager extends AbstractManager {
   prepareArgs(definition, args) {
     return args;
   }
 
-  create(environment, { name, env }, args, dynamicScope) {
-    runInDebug(() => this._pushEngineToDebugStack(`engine:${name}`, env));
+  create(environment, { name }, args, dynamicScope) {
+    runInDebug(() => this._pushEngineToDebugStack(`engine:${name}`, environment));
 
     dynamicScope.outletState = UNDEFINED_REFERENCE;
 
-    let engine = env.owner.buildChildEngineInstance(name);
+    let engine = environment.owner.buildChildEngineInstance(name);
 
     engine.boot();
 
-    return { engine };
+    return engine;
   }
 
-  layoutFor(definition, { engine }, env) {
+  layoutFor(definition, engine, env) {
     let template = engine.lookup(`template:application`);
     return env.getCompiledBlock(OutletLayoutCompiler, template);
   }
 
-  getSelf({ engine }) {
+  getSelf(engine) {
     let applicationFactory = engine[FACTORY_FOR](`controller:application`);
     let factory = applicationFactory || generateControllerFactory(engine, 'application');
     return new RootReference(factory.create());
@@ -87,7 +125,7 @@ class MountManager extends AbstractManager {
     return null;
   }
 
-  getDestructor({ engine }) {
+  getDestructor(engine) {
     return engine;
   }
 

From a2b168490d1b75d64e5ea654069d2ec09bb1e9de Mon Sep 17 00:00:00 2001
From: Michael Donaldson <mike@mike-donaldson.com>
Date: Thu, 2 Mar 2017 10:34:59 +0000
Subject: [PATCH 2/2] Cleanup mount syntax refactor

---
 packages/ember-glimmer/lib/syntax/mount.js | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/packages/ember-glimmer/lib/syntax/mount.js b/packages/ember-glimmer/lib/syntax/mount.js
index bc6b1a270fb..564c1cd0d50 100644
--- a/packages/ember-glimmer/lib/syntax/mount.js
+++ b/packages/ember-glimmer/lib/syntax/mount.js
@@ -64,7 +64,6 @@ class DynamicEngineReference {
     this.nameRef = nameRef;
     this.env = env;
     this.symbolTable = symbolTable;
-    this.args = args;
     this._lastName = undefined;
     this._lastDef = undefined;
   }
@@ -87,7 +86,7 @@ class DynamicEngineReference {
     }
 
     this._lastName = nameOrDef;
-    this._lastDef = new MountDefinition(nameOrDef, env);
+    this._lastDef = new MountDefinition(nameOrDef);
 
     return this._lastDef;
   }
@@ -144,8 +143,7 @@ class MountManager extends AbstractManager {
 const MOUNT_MANAGER = new MountManager();
 
 class MountDefinition extends ComponentDefinition {
-  constructor(name, env) {
+  constructor(name) {
     super(name, MOUNT_MANAGER, null);
-    this.env = env;
   }
 }