treat binding values as expressions

src/generators/dom/visitors/Component.js

@@ -1,5 +1,6 @@
 import deindent from '../../../utils/deindent.js';
 import CodeBuilder from '../../../utils/CodeBuilder.js';
+import flattenReference from '../../../utils/flattenReference.js';
 import addComponentAttributes from './attributes/addComponentAttributes.js';
 
 function capDown ( name ) {

src/generators/dom/visitors/attributes/addComponentAttributes.js

@@ -1,4 +1,4 @@
-import createBinding from './binding/index.js';
+import addComponentBinding from './addComponentBinding.js';
 import deindent from '../../../../utils/deindent.js';
 
 export default function addComponentAttributes ( generator, node, local ) {
@@ -112,7 +112,7 @@ export default function addComponentAttributes ( generator, node, local ) {
 		}
 
 		else if ( attribute.type === 'Binding' ) {
-			createBinding( generator, node, attribute, generator.current, local );
+			addComponentBinding( generator, node, attribute, generator.current, local );
 		}
 
 		else if ( attribute.type === 'Ref' ) {

src/generators/dom/visitors/attributes/addComponentBinding.js

@@ -0,0 +1,98 @@
+import deindent from '../../../../utils/deindent.js';
+import isReference from '../../../../utils/isReference.js';
+import flattenReference from '../../../../utils/flattenReference.js';
+
+export default function createBinding ( generator, node, attribute, current, local ) {
+	const { name, parts, keypath } = flattenReference( attribute.value );
+
+	const contextual = name in current.contexts;
+
+	if ( contextual && !~local.allUsedContexts.indexOf( name ) ) {
+		local.allUsedContexts.push( name );
+	}
+
+	let obj;
+	let prop;
+	let value;
+
+	if ( contextual ) {
+		obj = current.listNames[ name ];
+		prop = current.indexNames[ name ];
+		value = keypath;
+	} else {
+		prop = `'${parts.slice( -1 )}'`;
+		obj = parts.length > 1 ? `root.${parts.slice( 0, -1 ).join( '.' )}` : `root`;
+		value = `root.${keypath}`;
+	}
+
+	local.bindings.push({ name: attribute.name, value, obj, prop });
+
+	let setter;
+
+	if ( contextual ) {
+		// find the top-level property that this is a child of
+		let fragment = current;
+		let prop = name;
+
+		do {
+			if ( fragment.expression && fragment.context === prop ) {
+				if ( !isReference( fragment.expression ) ) {
+					// TODO this should happen in prior validation step
+					throw new Error( `${prop} is read-only, it cannot be bound` );
+				}
+
+				prop = flattenReference( fragment.expression ).name;
+			}
+		} while ( fragment = fragment.parent );
+
+		generator.expectedProperties[ prop ] = true;
+
+		const listName = current.listNames[ name ];
+		const indexName = current.indexNames[ name ];
+
+		const context = local.isComponent ? `_context` : `__svelte`;
+
+		setter = deindent`
+			var list = this.${context}.${listName};
+			var index = this.${context}.${indexName};
+			list[index]${parts.slice( 1 ).map( part => `.${part}` ).join( '' )} = ${value};
+
+			component._set({ ${prop}: component.get( '${prop}' ) });
+		`;
+	} else {
+		if ( parts.length > 1 ) {
+			setter = deindent`
+				var ${name} = component.get( '${name}' );
+				${name}.${parts.slice( 1 ).join( '.' )} = ${value};
+				component._set({ ${name}: ${name} });
+			`;
+		} else {
+			setter = `component._set({ ${keypath}: value });`;
+		}
+
+		generator.expectedProperties[ name ] = true;
+	}
+
+	generator.hasComplexBindings = true;
+
+	local.init.addBlock( deindent`
+		var ${local.name}_updating = false;
+
+		component._bindings.push( function () {
+			if ( ${local.name}._torndown ) return;
+			${local.name}.observe( '${attribute.name}', function ( value ) {
+				${local.name}_updating = true;
+				${setter}
+				${local.name}_updating = false;
+			});
+		});
+	` );
+
+	const dependencies = name in current.contexts ? current.contextDependencies[ name ] : [ name ];
+
+	local.update.addBlock( deindent`
+		if ( !${local.name}_updating && ${dependencies.map( dependency => `'${dependency}' in changed` ).join( '||' )} ) {
+			${local.name}._set({ ${attribute.name}: ${contextual ? keypath : `root.${keypath}`} });
+		}
+	` );
+}

src/generators/dom/visitors/attributes/addElementAttributes.js

@@ -1,5 +1,5 @@
 import attributeLookup from './lookup.js';
-import createBinding from './binding/index.js';
+import addElementBinding from './addElementBinding';
 import deindent from '../../../../utils/deindent.js';
 import flattenReference from '../../../../utils/flattenReference.js';
 
@@ -204,7 +204,7 @@ export default function addElementAttributes ( generator, node, local ) {
 		}
 
 		else if ( attribute.type === 'Binding' ) {
-			createBinding( generator, node, attribute, generator.current, local );
+			addElementBinding( generator, node, attribute, generator.current, local );
 		}
 
 		else if ( attribute.type === 'Ref' ) {

src/generators/dom/visitors/attributes/addElementBinding.js

@@ -0,0 +1,144 @@
+import deindent from '../../../../utils/deindent.js';
+import isReference from '../../../../utils/isReference.js';
+import flattenReference from '../../../../utils/flattenReference.js';
+
+export default function createBinding ( generator, node, attribute, current, local ) {
+	const { name, parts, keypath } = flattenReference( attribute.value );
+
+	const contextual = name in current.contexts;
+
+	if ( contextual && !~local.allUsedContexts.indexOf( name ) ) {
+		local.allUsedContexts.push( name );
+	}
+
+	const handler = current.getUniqueName( `${local.name}ChangeHandler` );
+	let setter;
+
+	let eventName = 'change';
+	if ( node.name === 'input' ) {
+		const typeAttribute = node.attributes.find( attr => attr.type === 'Attribute' && attr.name === 'type' );
+		const type = typeAttribute ? typeAttribute.value[0].data : 'text'; // TODO in validation, should throw if type attribute is not static
+
+		if ( type !== 'checkbox' && type !== 'radio' ) {
+			eventName = 'input';
+		}
+	}
+
+	else if ( node.name === 'textarea' ) {
+		eventName = 'input';
+	}
+
+	const isMultipleSelect = node.name === 'select' && node.attributes.find( attr => attr.name.toLowerCase() === 'multiple' ); // TODO ensure that this is a static attribute
+	let value;
+
+	if ( node.name === 'select' ) {
+		if ( isMultipleSelect ) {
+			value = `[].map.call( ${local.name}.selectedOptions, function ( option ) { return option.__value; })`;
+		} else {
+			value = 'selectedOption && selectedOption.__value';
+		}
+	} else {
+		value = `${local.name}.${attribute.name}`;
+	}
+
+	if ( contextual ) {
+		// find the top-level property that this is a child of
+		let fragment = current;
+		let prop = name;
+
+		do {
+			if ( fragment.expression && fragment.context === prop ) {
+				if ( !isReference( fragment.expression ) ) {
+					// TODO this should happen in prior validation step
+					throw new Error( `${prop} is read-only, it cannot be bound` );
+				}
+
+				prop = flattenReference( fragment.expression ).name;
+			}
+		} while ( fragment = fragment.parent );
+
+		generator.expectedProperties[ prop ] = true;
+
+		const listName = current.listNames[ name ];
+		const indexName = current.indexNames[ name ];
+
+		const context = local.isComponent ? `_context` : `__svelte`;
+
+		setter = deindent`
+			var list = this.${context}.${listName};
+			var index = this.${context}.${indexName};
+			list[index]${parts.slice( 1 ).map( part => `.${part}` ).join( '' )} = ${value};
+
+			component._set({ ${prop}: component.get( '${prop}' ) });
+		`;
+	} else {
+		if ( parts.length > 1 ) {
+			setter = deindent`
+				var ${name} = component.get( '${name}' );
+				${name}.${parts.slice( 1 ).join( '.' )} = ${value};
+				component._set({ ${name}: ${name} });
+			`;
+		} else {
+			setter = `component._set({ ${keypath}: ${value} });`;
+		}
+
+		generator.expectedProperties[ name ] = true;
+	}
+
+	// special case
+	if ( node.name === 'select' && !isMultipleSelect ) {
+		setter = `var selectedOption = ${local.name}.selectedOptions[0] || ${local.name}.options[0];\n` + setter;
+	}
+
+	let updateElement;
+
+	if ( node.name === 'select' ) {
+		const value = generator.current.getUniqueName( 'value' );
+		const i = generator.current.getUniqueName( 'i' );
+		const option = generator.current.getUniqueName( 'option' );
+
+		const ifStatement = isMultipleSelect ?
+			deindent`
+				${option}.selected = ~${value}.indexOf( ${option}.__value );` :
+			deindent`
+				if ( ${option}.__value === ${value} ) {
+					${option}.selected = true;
+					break;
+				}`;
+
+		updateElement = deindent`
+			var ${value} = ${contextual ? keypath : `root.${keypath}`};
+			for ( var ${i} = 0; ${i} < ${local.name}.options.length; ${i} += 1 ) {
+				var ${option} = ${local.name}.options[${i}];
+
+				${ifStatement}
+			}
+		`;
+	} else {
+		updateElement = `${local.name}.${attribute.name} = ${contextual ? keypath : `root.${keypath}`};`;
+	}
+
+	local.init.addBlock( deindent`
+		var ${local.name}_updating = false;
+
+		function ${handler} () {
+			${local.name}_updating = true;
+			${setter}
+			${local.name}_updating = false;
+		}
+
+		${generator.helper( 'addEventListener' )}( ${local.name}, '${eventName}', ${handler} );
+	` );
+
+	node.initialUpdate = updateElement;
+
+	local.update.addLine( deindent`
+		if ( !${local.name}_updating ) {
+			${updateElement}
+		}
+	` );
+
+	generator.current.builders.teardown.addLine( deindent`
+		${generator.helper( 'removeEventListener' )}( ${local.name}, '${eventName}', ${handler} );
+	` );
+}

src/generators/dom/visitors/attributes/binding/index.js

@@ -1,190 +0,0 @@
-import deindent from '../../../../../utils/deindent.js';
-import isReference from '../../../../../utils/isReference.js';
-import flattenReference from '../../../../../utils/flattenReference.js';
-
-export default function createBinding ( generator, node, attribute, current, local ) {
-	const parts = attribute.value.split( '.' );
-
-	const deep = parts.length > 1;
-	const contextual = parts[0] in current.contexts;
-
-	if ( contextual && !~local.allUsedContexts.indexOf( parts[0] ) ) {
-		local.allUsedContexts.push( parts[0] );
-	}
-
-	if ( local.isComponent ) {
-		let obj;
-		let prop;
-		let value;
-
-		if ( contextual ) {
-			obj = current.listNames[ parts[0] ];
-			prop = current.indexNames[ parts[0] ];
-			value = attribute.value;
-		} else {
-			prop = `'${parts.slice( -1 )}'`;
-			obj = parts.length > 1 ? `root.${parts.slice( 0, -1 ).join( '.' )}` : `root`;
-			value = `root.${attribute.value}`;
-		}
-
-		local.bindings.push({ name: attribute.name, value, obj, prop });
-	}
-
-	const handler = current.getUniqueName( `${local.name}ChangeHandler` );
-	let setter;
-
-	let eventName = 'change';
-	if ( node.name === 'input' ) {
-		const typeAttribute = node.attributes.find( attr => attr.type === 'Attribute' && attr.name === 'type' );
-		const type = typeAttribute ? typeAttribute.value[0].data : 'text'; // TODO in validation, should throw if type attribute is not static
-
-		if ( type !== 'checkbox' && type !== 'radio' ) {
-			eventName = 'input';
-		}
-	}
-
-	else if ( node.name === 'textarea' ) {
-		eventName = 'input';
-	}
-
-	const isMultipleSelect = node.name === 'select' && node.attributes.find( attr => attr.name.toLowerCase() === 'multiple' ); // TODO ensure that this is a static attribute
-	let value;
-
-	if ( local.isComponent ) {
-		value = 'value';
-	} else if ( node.name === 'select' ) {
-		if ( isMultipleSelect ) {
-			value = `[].map.call( ${local.name}.selectedOptions, function ( option ) { return option.__value; })`;
-		} else {
-			value = 'selectedOption && selectedOption.__value';
-		}
-	} else {
-		value = `${local.name}.${attribute.name}`;
-	}
-
-	if ( contextual ) {
-		// find the top-level property that this is a child of
-		let fragment = current;
-		let prop = parts[0];
-
-		do {
-			if ( fragment.expression && fragment.context === prop ) {
-				if ( !isReference( fragment.expression ) ) {
-					// TODO this should happen in prior validation step
-					throw new Error( `${prop} is read-only, it cannot be bound` );
-				}
-
-				prop = flattenReference( fragment.expression ).name;
-			}
-		} while ( fragment = fragment.parent );
-
-		generator.expectedProperties[ prop ] = true;
-
-		const listName = current.listNames[ parts[0] ];
-		const indexName = current.indexNames[ parts[0] ];
-
-		const context = local.isComponent ? `_context` : `__svelte`;
-
-		setter = deindent`
-			var list = this.${context}.${listName};
-			var index = this.${context}.${indexName};
-			list[index]${parts.slice( 1 ).map( part => `.${part}` ).join( '' )} = ${value};
-
-			component._set({ ${prop}: component.get( '${prop}' ) });
-		`;
-	} else {
-		if ( deep ) {
-			setter = deindent`
-				var ${parts[0]} = component.get( '${parts[0]}' );
-				${parts[0]}.${parts.slice( 1 ).join( '.' )} = ${value};
-				component._set({ ${parts[0]}: ${parts[0]} });
-			`;
-		} else {
-			setter = `component._set({ ${attribute.value}: ${value} });`;
-		}
-
-		generator.expectedProperties[ parts[0] ] = true;
-	}
-
-	// special case
-	if ( node.name === 'select' && !isMultipleSelect ) {
-		setter = `var selectedOption = ${local.name}.selectedOptions[0] || ${local.name}.options[0];\n` + setter;
-	}
-
-	if ( local.isComponent ) {
-		generator.hasComplexBindings = true;
-
-		local.init.addBlock( deindent`
-			var ${local.name}_updating = false;
-
-			component._bindings.push( function () {
-				if ( ${local.name}._torndown ) return;
-				${local.name}.observe( '${attribute.name}', function ( value ) {
-					${local.name}_updating = true;
-					${setter}
-					${local.name}_updating = false;
-				});
-			});
-		` );
-
-		const dependencies = parts[0] in current.contexts ? current.contextDependencies[ parts[0] ] : [ parts[0] ];
-
-		local.update.addBlock( deindent`
-			if ( !${local.name}_updating && ${dependencies.map( dependency => `'${dependency}' in changed` ).join( '||' )} ) {
-				${local.name}._set({ ${attribute.name}: ${contextual ? attribute.value : `root.${attribute.value}`} });
-			}
-		` );
-	} else {
-		let updateElement;
-
-		if ( node.name === 'select' ) {
-			const value = generator.current.getUniqueName( 'value' );
-			const i = generator.current.getUniqueName( 'i' );
-			const option = generator.current.getUniqueName( 'option' );
-
-			const ifStatement = isMultipleSelect ?
-				deindent`
-					${option}.selected = ~${value}.indexOf( ${option}.__value );` :
-				deindent`
-					if ( ${option}.__value === ${value} ) {
-						${option}.selected = true;
-						break;
-					}`;
-
-			updateElement = deindent`
-				var ${value} = ${contextual ? attribute.value : `root.${attribute.value}`};
-				for ( var ${i} = 0; ${i} < ${local.name}.options.length; ${i} += 1 ) {
-					var ${option} = ${local.name}.options[${i}];
-
-					${ifStatement}
-				}
-			`;
-		} else {
-			updateElement = `${local.name}.${attribute.name} = ${contextual ? attribute.value : `root.${attribute.value}`};`;
-		}
-
-		local.init.addBlock( deindent`
-			var ${local.name}_updating = false;
-
-			function ${handler} () {
-				${local.name}_updating = true;
-				${setter}
-				${local.name}_updating = false;
-			}
-
-			${generator.helper( 'addEventListener' )}( ${local.name}, '${eventName}', ${handler} );
-		` );
-
-		node.initialUpdate = updateElement;
-
-		local.update.addLine( deindent`
-			if ( !${local.name}_updating ) {
-				${updateElement}
-			}
-		` );
-
-		generator.current.builders.teardown.addLine( deindent`
-			${generator.helper( 'removeEventListener' )}( ${local.name}, '${eventName}', ${handler} );
-		` );
-	}
-}

src/generators/server-side-rendering/index.js

@@ -1,5 +1,6 @@
 import deindent from '../../utils/deindent.js';
 import CodeBuilder from '../../utils/CodeBuilder.js';
+import flattenReference from '../../utils/flattenReference.js';
 import processCss from '../shared/processCss.js';
 import visitors from './visitors/index.js';
 import Generator from '../Generator.js';
@@ -16,11 +17,13 @@ class SsrGenerator extends Generator {
 			this.current.conditions.map( c => `(${c})` )
 		);
 
+		const { keypath } = flattenReference( binding.value );
+
 		this.bindings.push( deindent`
 			if ( ${conditions.join( '&&' )} ) {
 				tmp = ${name}.data();
-				if ( '${binding.value}' in tmp ) {
+				if ( '${keypath}' in tmp ) {
-					root.${binding.name} = tmp.${binding.value};
+					root.${binding.name} = tmp.${keypath};
 					settled = false;
 				}
 			}

src/generators/server-side-rendering/visitors/Component.js

@@ -1,3 +1,5 @@
+import flattenReference from '../../../utils/flattenReference.js';
+
 export default {
 	enter ( generator, node ) {
 		function stringify ( chunk ) {
@@ -42,8 +44,8 @@ export default {
 				return `${attribute.name}: ${value}`;
 			})
 			.concat( bindings.map( binding => {
-				const parts = binding.value.split( '.' );
+				const { name, keypath } = flattenReference( binding.value );
-				const value = parts[0] in generator.current.contexts ? binding.value : `root.${binding.value}`;
+				const value = name in generator.current.contexts ? keypath : `root.${keypath}`;
 				return `${binding.name}: ${value}`;
 			}))
 			.join( ', ' );

src/parse/read/directives.js

@@ -1,4 +1,5 @@
 import { parse } from 'acorn';
+import { parseExpressionAt } from 'acorn';
 import spaces from '../../utils/spaces.js';
 
 export function readEventHandlerDirective ( parser, start, name ) {
@@ -66,7 +67,7 @@ export function readEventHandlerDirective ( parser, start, name ) {
 }
 
 export function readBindingDirective ( parser, start, name ) {
-	let value = name; // shorthand – bind:foo equivalent to bind:foo='foo'
+	let value;
 
 	if ( parser.eat( '=' ) ) {
 		const quoteMark = (
@@ -75,12 +76,37 @@ export function readBindingDirective ( parser, start, name ) {
 			null
 		);
 
-		value = parser.read( /([a-zA-Z_$][a-zA-Z0-9_$]*)(\.[a-zA-Z_$][a-zA-Z0-9_$]*)*/ );
+		const a = parser.index;
-		if ( !value ) parser.error( `Expected valid property name` );
+
+		// this is a bit of a hack so that we can give Acorn something parseable
+		let b;
+		if ( quoteMark ) {
+			b = parser.index = parser.template.indexOf( quoteMark, parser.index );
+		} else {
+			parser.readUntil( /[\s\r\n\/>]/ );
+			b = parser.index;
+		}
+
+		const source = spaces( a ) + parser.template.slice( a, b );
+		value = parseExpressionAt( source, a );
+
+		if ( value.type !== 'Identifier' && value.type !== 'MemberExpression' ) {
+			parser.error( `Expected valid property name` );
+		}
+
+		parser.allowWhitespace();
 
 		if ( quoteMark ) {
 			parser.eat( quoteMark, true );
 		}
+	} else {
+		// shorthand – bind:foo equivalent to bind:foo='foo'
+		value = {
+			type: 'Identifier',
+			start: start + 5,
+			end: parser.index,
+			name
+		};
 	}
 
 	return {

src/utils/flattenReference.js

@@ -12,5 +12,5 @@ export default function flatten ( node ) {
 	if ( !name ) return null;
 
 	parts.unshift( name );
-	return { name, keypath: parts.join( '.' ) };
+	return { name, parts, keypath: parts.join( '.' ) };
 }

test/generator/samples/binding-input-checkbox/_config.js

@@ -2,7 +2,9 @@ export default {
 	data: {
 		foo: true
 	},
+
 	html: `<input type="checkbox">\n<p>true</p>`,
+
 	test ( assert, component, target, window ) {
 		const input = target.querySelector( 'input' );
 		assert.equal( input.checked, true );

test/parser/samples/binding-shorthand/output.json

@@ -15,7 +15,12 @@
 						"end": 16,
 						"type": "Binding",
 						"name": "foo",
-						"value": "foo"
+						"value": {
+							"type": "Identifier",
+							"start": 13,
+							"end": 16,
+							"name": "foo"
+						}
 					}
 				],
 				"children": []

test/parser/samples/binding/output.json

@@ -15,7 +15,12 @@
 						"end": 24,
 						"type": "Binding",
 						"name": "value",
-						"value": "name"
+						"value": {
+							"start": 19,
+							"end": 23,
+							"type": "Identifier",
+							"name": "name"
+						}
 					}
 				],
 				"children": []