add expression scoping to data

packages/moon/dist/moon.js

@@ -86,6 +86,17 @@
 	 */
 
 	var attributeRE = /\s*([\w\d-_:@]*)(?:=(?:("[^"]*"|'[^']*')|{([^{}]*)}))?/g;
+	/**
+	 * Capture the variables in expressions to scope them within the data
+	 * parameter. This ignores property names and deep object accesses.
+	 */
+
+	var expressionRE = /"[^"]*"|'[^']*'|\d+[a-zA-Z$_]\w*|\.[a-zA-Z$_]\w*|[a-zA-Z$_]\w*:|([a-zA-Z$_]\w*)/g;
+	/**
+	 * List of global variables to ignore in expression scoping
+	 */
+
+	var globals = ["NaN", "false", "in", "null", "this", "true", "typeof", "undefined", "window"];
 	/**
 	 * Convert a token into a string, accounting for `<text/>` components.
 	 *
@@ -278,7 +289,9 @@
 					type: "tagOpen",
 					value: "text",
 					attributes: {
-						"": expression
+						"": expression.replace(expressionRE, function (match, name) {
+							return name === undefined || globals.indexOf(name) !== -1 ? match : "data." + name;
+						})
 					},
 					closed: true
 				});

packages/moon/src/compiler/lexer/lexer.js

@@ -13,6 +13,17 @@ const typeRE = /<([\w\d-_]+)([^>]*?)(\/?)>/g;
  */
 const attributeRE = /\s*([\w\d-_:@]*)(?:=(?:("[^"]*"|'[^']*')|{([^{}]*)}))?/g;
 
+/**
+ * Capture the variables in expressions to scope them within the data
+ * parameter. This ignores property names and deep object accesses.
+ */
+const expressionRE = /"[^"]*"|'[^']*'|\d+[a-zA-Z$_]\w*|\.[a-zA-Z$_]\w*|[a-zA-Z$_]\w*:|([a-zA-Z$_]\w*)/g;
+
+/**
+ * List of global variables to ignore in expression scoping
+ */
+const globals = ["NaN", "false", "in", "null", "this", "true", "typeof", "undefined", "window"];
+
 /**
  * Convert a token into a string, accounting for `<text/>` components.
  *
@@ -188,8 +199,8 @@ export function lex(input) {
 					// expression.
 					attributes[attributeKey] =
 						attributeExpression === undefined ?
-						attributeValue :
-						attributeExpression;
+							attributeValue :
+							attributeExpression;
 				}
 			}
 
@@ -225,7 +236,11 @@ export function lex(input) {
 				type: "tagOpen",
 				value: "text",
 				attributes: {
-					"": expression
+					"": expression.replace(expressionRE, (match, name) =>
+						(name === undefined || globals.indexOf(name) !== -1) ?
+							match :
+							`data.${name}`
+					)
 				},
 				closed: true
 			});