Add YieldTag to parser and generator

compiler/generate/index.js

@@ -516,6 +516,7 @@ export default function generate ( parsed, source, options ) {
 			};
 
 			this.root = options.root;
+			this.yield = options.yield;
 
 			${initStatements.join( '\n\n' )}
 		}

compiler/generate/visitors/Element.js

@@ -1,9 +1,11 @@
 import deindent from '../utils/deindent.js';
 import addComponentAttributes from './attributes/addComponentAttributes.js';
 import addElementAttributes from './attributes/addElementAttributes.js';
+import counter from '../utils/counter.js';
 
 export default {
 	enter ( generator, node ) {
+		const hasChildren = node.children.length > 0;
 		const isComponent = node.name in generator.components;
 		const name = generator.current.counter( isComponent ? `${node.name[0].toLowerCase()}${node.name.slice( 1 )}` : node.name );
 
@@ -27,13 +29,49 @@ export default {
 
 			addComponentAttributes( generator, node, local );
 
+			const componentInitProperties = [
+				`target: ${!isToplevel ? generator.current.target: 'null'}`,
+				'root: component.root || component'
+			];
+			// Component has children
+			if ( hasChildren ) {
+				const yieldName = `render${name}YieldFragment`;
+
+				// {{YIELD STUFF}}
+				generator.push({
+					useAnchor: true,
+					name: generator.current.counter(yieldName),
+					target: 'target',
+					localElementDepth: 0,
+
+					initStatements: [],
+					mountStatements: [],
+					updateStatements: [],
+					teardownStatements: [],
+
+					counter: counter()
+				});
+
+				node.children.forEach( generator.visit );
+				generator.addRenderer( generator.current );
+				generator.pop();
+
+				// Don't render children twice
+				node.children = [];
+
+				generator.current.initStatements.push(`var ${name}_yieldFragment = ${yieldName}( root, component );`);
+				generator.current.updateStatements.push(`${name}_yieldFragment.update ( changed, root );`);
+
+				componentInitProperties.push(`yield: ${name}_yieldFragment`);
+			}
+
+			const statements = [];
+
 			if ( local.staticAttributes.length || local.dynamicAttributes.length || local.bindings.length ) {
 				const initialProps = local.staticAttributes
 					.concat( local.dynamicAttributes )
 					.map( attribute => `${attribute.name}: ${attribute.value}` );
 
-				const statements = [];
-
 				if ( initialProps.length ) {
 					statements.push( deindent`
 						var ${name}_initialData = {
@@ -53,24 +91,17 @@ export default {
 
 					statements.push( bindings.join( '\n' ) );
 				}
+				componentInitProperties.push(`data: ${name}_initialData`);
+			}
 
-				local.init.unshift( deindent`
-					${statements.join( '\n\n' )}
+			local.init.unshift( deindent`
+				${statements.join( '\n\n' )}
+
+				var ${name} = new template.components.${node.name}({
+					${componentInitProperties.join(',\n')}
+				});
+			` );
 
-					var ${name} = new template.components.${node.name}({
-						target: ${!isToplevel ? generator.current.target: 'null'},
-						root: component.root || component,
-						data: ${name}_initialData
-					});
-				` );
-			} else {
-				local.init.unshift( deindent`
-					var ${name} = new template.components.${node.name}({
-						target: ${!isToplevel ? generator.current.target: 'null'},
-						root: component.root || component
-					});
-				` );
-			}
 
 			if ( isToplevel ) {
 				local.mount.unshift( `${name}.mount( target, anchor );` );

compiler/generate/visitors/YieldTag.js

@@ -0,0 +1,7 @@
+export default {
+	enter ( generator ) {
+	  const anchor = generator.createAnchor( 'yield', 'yield' );
+		generator.current.mountStatements.push(`component.yield && component.yield.mount( ${generator.current.target}, ${anchor} );`);
+		generator.current.teardownStatements.push(`component.yield && component.yield.teardown( detach );`);
+	}
+};

compiler/generate/visitors/index.js

@@ -4,12 +4,14 @@ import Element from './Element.js';
 import IfBlock from './IfBlock.js';
 import MustacheTag from './MustacheTag.js';
 import Text from './Text.js';
+import YieldTag from './YieldTag.js';
 
 export default {
 	Comment,
 	EachBlock,
 	Element,
 	IfBlock,
 	MustacheTag,
-	Text
+	Text,
+	YieldTag
 };

compiler/parse/state/mustache.js

@@ -177,6 +177,19 @@ export default function mustache ( parser ) {
 		parser.stack.push( block );
 	}
 
+	// {{yield}}
+	else if ( parser.eat( 'yield' ) ) {
+
+		parser.allowWhitespace();
+		parser.eat( '}}', true );
+
+		parser.current().children.push({
+			start,
+			end: parser.index,
+			type: 'YieldTag'
+		});
+	}
+
 	else {
 		const expression = readExpression( parser );
 

test/compiler/component-yield-if/Widget.html

@@ -0,0 +1,15 @@
+<p>
+  {{#if show}}
+    {{yield}}
+  {{/if}}
+</p>
+<script>
+  export default {
+    data(){
+      return {
+        show: false
+      }
+    }
+  }
+
+</script>

test/compiler/component-yield-if/_config.js

@@ -0,0 +1,13 @@
+export default {
+	html: '<div><p></p></div>',
+	test ( assert, component, target ) {
+		const widget = component.refs.widget;
+		assert.equal( widget.get( 'show' ), false );
+		widget.set({show: true});
+		assert.equal( target.innerHTML, '<div><p>Hello<!--yield--><!--#if show--></p></div>' );
+		component.set({data: 'World'});
+		assert.equal( target.innerHTML, '<div><p>World<!--yield--><!--#if show--></p></div>' );
+		widget.set({show: false});
+		assert.equal( target.innerHTML, '<div><p><!--#if show--></p></div>' );
+	}
+}

test/compiler/component-yield-if/main.html

@@ -0,0 +1,14 @@
+<div>
+	<Widget ref:widget>{{data}}</Widget>
+</div>
+<script>
+	import Widget from './Widget.html'
+	export default {
+		components: { Widget },
+		data(){
+			return {
+				data: "Hello"
+			}
+		}
+	}
+</script>

test/compiler/component-yield-parent/Widget.html

@@ -0,0 +1 @@
+<p>{{yield}}</p>

test/compiler/component-yield-parent/_config.js

@@ -0,0 +1,9 @@
+export default {
+	html: '<div><p>Hello</p></div>',
+	test ( assert, component, target ) {
+		assert.equal( component.get( 'data' ), 'Hello' );
+		component.set({data: 'World'})
+		assert.equal( component.get( 'data' ), 'World' );
+		assert.equal( target.innerHTML, '<div><p>World<!--yield--></p></div>' );
+	}
+}

test/compiler/component-yield-parent/main.html

@@ -0,0 +1,14 @@
+<div>
+	<Widget>{{data}}</Widget>
+</div>
+<script>
+	import Widget from './Widget.html'
+	export default {
+		components: { Widget },
+		data(){
+			return {
+				data: "Hello"
+			}
+		}
+	}
+</script>

test/compiler/component-yield/_config.js

@@ -0,0 +1,3 @@
+export default {
+  html: '<p>Hello</p>'
+}

test/compiler/component-yield/main.html

@@ -0,0 +1,15 @@
+<p>
+  Hello
+  {{#if test}}
+    {{yield}}
+  {{/if}}
+</p>
+<script>
+  export default {
+    data(){
+      return {
+        test: true
+      }
+    }
+  }
+</script>

test/parser/yield/input.html

@@ -0,0 +1 @@
+{{yield}}

test/parser/yield/output.json

@@ -0,0 +1,14 @@
+{
+  "html": {
+    "start": 0,
+    "end": 9,
+    "type": "Fragment",
+    "children": [
+      {
+        "start": 0,
+        "end": 9,
+        "type": "YieldTag"
+      }
+    ]
+  }
+}