refactor(dart/transform): Create common dumbEval function

modules_dart/transform/lib/src/transform/common/directive_metadata_reader.dart

@@ -12,6 +12,8 @@ import 'package:angular2/src/transform/common/annotation_matcher.dart';
 import 'package:angular2/src/transform/common/interface_matcher.dart';
 import 'package:barback/barback.dart' show AssetId;
 
+import 'dumb_eval.dart';
+
 class DirectiveMetadataReader {
   final _DirectiveMetadataVisitor _visitor;
   final TemplateCompiler _templateCompiler;
@@ -53,22 +55,11 @@ class DirectiveMetadataReader {
   }
 }
 
-/// Visitor that attempts to evaluate a provided `node` syntactically.
-///
-/// This lack of semantic information means it cannot do much - for
-/// example, it can create a list from a list literal and combine adjacent
-/// strings but cannot determine that an identifier is a constant string,
-/// even if that identifier is defined in the same [CompilationUnit].
-///
-/// Returns the result of evaluation or [ConstantEvaluator.NOT_A_CONSTANT]
-/// where appropriate.
-final ConstantEvaluator _evaluator = new ConstantEvaluator();
-
 /// Evaluates the [Map] represented by `expression` and adds all `key`,
 /// `value` pairs to `map`. If `expression` does not evaluate to a [Map],
 /// throws a descriptive [FormatException].
 void _populateMap(Expression expression, Map map, String propertyName) {
-  var evaluated = expression.accept(_evaluator);
+  var evaluated = dumbEval(expression);
   if (evaluated is! Map) {
     throw new FormatException(
         'Angular 2 expects a Map but could not understand the value for '
@@ -87,7 +78,7 @@ void _populateMap(Expression expression, Map map, String propertyName) {
 /// descriptive [FormatException].
 void _populateList(
     Expression expression, List<String> list, String propertyName) {
-  var evaluated = expression.accept(_evaluator);
+  var evaluated = dumbEval(expression);
   if (evaluated is! List) {
     throw new FormatException(
         'Angular 2 expects a List but could not understand the value for '
@@ -100,7 +91,7 @@ void _populateList(
 /// Evaluates `node` and expects that the result will be a string. If not,
 /// throws a [FormatException].
 String _expressionToString(Expression node, String nodeDescription) {
-  var value = node.accept(_evaluator);
+  var value = dumbEval(node);
   if (value is! String) {
     throw new FormatException(
         'Angular 2 could not understand the value '

modules_dart/transform/lib/src/transform/common/dumb_eval.dart

@@ -0,0 +1,26 @@
+library angular2.transform.common.dumb_eval;
+
+import 'package:analyzer/analyzer.dart';
+
+final _constantEvaluator = new ConstantEvaluator();
+
+/// The value returned if the result of `dumbEval` is not a constant.
+final NOT_A_CONSTANT = ConstantEvaluator.NOT_A_CONSTANT;
+
+/// Performs a very limited syntactic evaluation of `expr`.
+///
+/// This lack of semantic information means this method cannot do much - for
+/// example, it can create a list from a list literal and combine adjacent
+/// strings but cannot determine that an identifier is a constant string,
+/// even if that identifier is defined in the same [CompilationUnit].
+///
+/// Returns the result of evaluation or [NOT_A_CONSTANT] where appropriate.
+dynamic dumbEval(Expression expr) {
+  var val;
+  if (expr is SimpleStringLiteral) {
+    val = stringLiteralToString(expr);
+  } else {
+    val = expr.accept(_constantEvaluator);
+  }
+  return val != NOT_A_CONSTANT ? val : null;
+}

modules_dart/transform/lib/src/transform/inliner_for_test/transformer.dart

@@ -7,6 +7,7 @@ import 'package:analyzer/src/generated/ast.dart';
 import 'package:angular2/src/core/compiler/xhr.dart' show XHR;
 import 'package:angular2/src/transform/common/annotation_matcher.dart';
 import 'package:angular2/src/transform/common/asset_reader.dart';
+import 'package:angular2/src/transform/common/dumb_eval.dart';
 import 'package:angular2/src/transform/common/async_string_writer.dart';
 import 'package:angular2/src/transform/common/logging.dart';
 import 'package:angular2/src/transform/common/options.dart';
@@ -119,7 +120,7 @@ class _ViewPropInliner extends RecursiveAstVisitor<Object> {
 
   @override
   Object visitNamedExpression(NamedExpression node) {
-    if (_isInlining && node is NamedExpression) {
+    if (_isInlining) {
       if (node.name is! Label || node.name.label is! SimpleIdentifier) {
         throw new FormatException(
             'Angular 2 currently only supports simple identifiers in directives.',
@@ -141,7 +142,7 @@ class _ViewPropInliner extends RecursiveAstVisitor<Object> {
   }
 
   void _populateStyleUrls(NamedExpression node) {
-    var urls = _dumbEval(node.expression);
+    var urls = dumbEval(node.expression);
     if (urls is! List) {
       logger.warning('styleUrls is not a List of Strings (${node.expression})');
       return;
@@ -162,7 +163,7 @@ class _ViewPropInliner extends RecursiveAstVisitor<Object> {
   }
 
   void _populateTemplateUrl(NamedExpression node) {
-    var url = _dumbEval(node.expression);
+    var url = dumbEval(node.expression);
     if (url is! String) {
       logger.warning('template url is not a String (${node.expression})');
       return;
@@ -185,15 +186,3 @@ class _ViewPropInliner extends RecursiveAstVisitor<Object> {
     });
   }
 }
-
-final _constantEvaluator = new ConstantEvaluator();
-
-dynamic _dumbEval(Expression expr) {
-  var val;
-  if (expr is SimpleStringLiteral) {
-    val = stringLiteralToString(expr);
-  } else {
-    val = expr.accept(_constantEvaluator);
-  }
-  return val != ConstantEvaluator.NOT_A_CONSTANT ? val : null;
-}