dart2js: Accept named holes in js-templates.

sdk/lib/_internal/compiler/implementation/js/builder.dart

Index: sdk/lib/_internal/compiler/implementation/js/builder.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js/builder.dart b/sdk/lib/_internal/compiler/implementation/js/builder.dart
index 838dbc82dbae9b2bb2f3addc4eae4cba91eede68..47a285e01eb287ed3c5db07f2f24574adb562b4f 100644
--- a/sdk/lib/_internal/compiler/implementation/js/builder.dart
+++ b/sdk/lib/_internal/compiler/implementation/js/builder.dart
@@ -208,7 +208,9 @@ class JsBuilder {
   Expression call(String source, [var arguments]) {
     Template template = _findExpressionTemplate(source);
     if (arguments == null) return template.instantiate([]);
-    return template.instantiate(arguments is List ? arguments : [arguments]);
+    // We allow a single argument to be given directly.
+    if (arguments is! List && arguments is! Map) arguments = [arguments];
+    return template.instantiate(arguments);
   }
 
   /**
@@ -217,7 +219,9 @@ class JsBuilder {
   Statement statement(String source, [var arguments]) {
     Template template = _findStatementTemplate(source);
     if (arguments == null) return template.instantiate([]);
-    return template.instantiate(arguments is List ? arguments : [arguments]);
+    // We allow a single argument to be given directly.
+    if (arguments is! List && arguments is! Map) arguments = [arguments];
+    return template.instantiate(arguments);
   }
 
   /**
@@ -402,6 +406,11 @@ class MiniJsParser {
   int position = 0;
   bool skippedNewline = false;  // skipped newline in last getToken?
   final String src;
+
+  /// Whether the template uses named or positional holes.
+  ///
+  /// Initially set to `null`, and updated when the first hole is encountered.
+  bool hasNamedHoles;
   final List<InterpolatedNode> interpolatedValues = <InterpolatedNode>[];
 
   static const NONE = -1;
@@ -664,6 +673,40 @@ class MiniJsParser {
     throw new MiniJsParserError(this, message);
   }
 
+  /// Returns either the name for the hole, or its integer position.
+  parseHash() {
+    String holeName = lastToken;
+    if (acceptCategory(ALPHA)) {
+      // Named hole. Example: 'function #funName() { ... }'
+      if (hasNamedHoles == false) {
+        error('Holes must all be positional or named. $holeName');
+      }
+      hasNamedHoles = true;
+      return holeName;
+    } else if (acceptCategory(LBRACE)) {
+      // Named guarded hole. Example: 'function #{funName}() { ... }'
+      String holeName = lastToken;
+      if (!acceptCategory(ALPHA)) {
+        error('Named hole does not contain alpha-characters.');
+      }
+      if (!acceptCategory(RBRACE)) {
+        error('Named hole is not correctly terminated with `}`');
+      }
+      if (hasNamedHoles == false) {
+        error('Holes must all be positional or named. $holeName');
+      }
+      hasNamedHoles = true;
+      return holeName;
+    } else {
+      if (hasNamedHoles == true) {
+        error('Holes must all be positional or named. $holeName');
+      }
+      hasNamedHoles = false;
+      int position = interpolatedValues.length;
+      return position;
+    }
+  }
+
   Expression parsePrimary() {
     String last = lastToken;
     if (acceptCategory(ALPHA)) {
@@ -705,8 +748,8 @@ class MiniJsParser {
       Expression expression = new RegExpLiteral(regexp + flags);
       return expression;
     } else if (acceptCategory(HASH)) {
-      InterpolatedExpression expression =
-          new InterpolatedExpression(interpolatedValues.length);
+      var name = parseHash();
+      InterpolatedExpression expression = new InterpolatedExpression(name);
       interpolatedValues.add(expression);
       return expression;
     } else {
@@ -732,8 +775,8 @@ class MiniJsParser {
     if (!acceptCategory(RPAREN)) {
       for (;;) {
         if (acceptCategory(HASH)) {
-          InterpolatedParameter parameter =
-              new InterpolatedParameter(interpolatedValues.length);
+          var name = parseHash();
+          InterpolatedParameter parameter = new InterpolatedParameter(name);
           interpolatedValues.add(parameter);
           params.add(parameter);
         } else {
@@ -766,8 +809,9 @@ class MiniJsParser {
       } else if (acceptCategory(SYMBOL)) {  // e.g. void
         propertyName = new LiteralString('"$identifier"');
       } else if (acceptCategory(HASH)) {
+        var name = parseHash();
         InterpolatedLiteral interpolatedLiteral =
-            new InterpolatedLiteral(interpolatedValues.length);
+            new InterpolatedLiteral(name);
         interpolatedValues.add(interpolatedLiteral);
         propertyName = interpolatedLiteral;
       } else {
@@ -833,8 +877,8 @@ class MiniJsParser {
 
   Expression getDotRhs(Expression receiver) {
     if (acceptCategory(HASH)) {
-      InterpolatedSelector property =
-          new InterpolatedSelector(interpolatedValues.length);
+      var name = parseHash();
+      InterpolatedSelector property = new InterpolatedSelector(name);
       interpolatedValues.add(property);
       return new PropertyAccess(receiver, property);
     }