try to parse expressions as javascript before interpreting them as an identifier (#424)

src/parse/read/expression.js

@@ -3,6 +3,14 @@ import { parseExpressionAt } from 'acorn';
 export default function readExpression ( parser ) {
 	const start = parser.index;
 
+	parser.index = start;
+
+	try {
+		const node = parseExpressionAt( parser.template, parser.index );
+		parser.index = node.end;
+
+		return node;
+	} catch ( err ) {
 		const name = parser.readUntil( /\s*}}/ );
 		if ( name && /^[a-z]+$/.test( name ) ) {
 			return {
@@ -12,15 +20,6 @@ export default function readExpression ( parser ) {
 				name
 			};
 		}
-
-	parser.index = start;
-
-	try {
-		const node = parseExpressionAt( parser.template, parser.index );
-		parser.index = node.end;
-
-		return node;
-	} catch ( err ) {
 		parser.acornError( err );
 	}
 }