Wrap as expressions with parens (#214)

Closes #213

CHANGELOG.md

@@ -1,3 +1,9 @@
+## 3.1.1
+
+* `Expression.asA` is now wrapped with parenthesis so that further calls may be
+  made on it as an expression.
+
+
 ## 3.1.0
 
 * Added `Expression.asA` for creating explicit casts:

lib/src/specs/expression.dart

@@ -46,11 +46,15 @@ abstract class Expression implements Spec {
 
   /// Returns the result of `this` `as` [other].
   Expression asA(Expression other) {
-    return new BinaryExpression._(
-      expression,
-      other,
-      'as',
-    );
+    return new CodeExpression(new Block.of([
+      const Code('('),
+      new BinaryExpression._(
+        expression,
+        other,
+        'as',
+      ).code,
+      const Code(')')
+    ]));
   }
 
   /// Returns accessing the index operator (`[]`) on `this`.

pubspec.yaml

@@ -1,5 +1,5 @@
 name: code_builder
-version: 3.1.0
+version: 3.1.1
 description: A fluent API for generating Dart code
 author: Dart Team <misc@dartlang.org>
 homepage: https://github.com/dart-lang/code_builder

test/specs/code/expression_test.dart

@@ -345,8 +345,8 @@ void main() {
 
   test('should emit an explicit cast', () {
     expect(
-      refer('foo').asA(refer('String')),
-      equalsDart('foo as String'),
+      refer('foo').asA(refer('String')).property('length'),
+      equalsDart('( foo as String ).length'),
     );
   });