Get codebase ready for actually supporting versioning.

utils/pub/sdk_source.dart

Index: utils/pub/sdk_source.dart
diff --git a/utils/pub/sdk_source.dart b/utils/pub/sdk_source.dart
index b64fd9c78014a9ce4f0dc8cc83c7005efdfd3566..bffba89c8a168e74da5cda6361b103c1fcc24040 100644
--- a/utils/pub/sdk_source.dart
+++ b/utils/pub/sdk_source.dart
@@ -25,10 +25,12 @@ class SdkSource extends Source {
    * involves symlinking the SDK library into the packages directory.
    */
   Future<bool> install(PackageId id, String destPath) {
-    var sourcePath = join(rootDir, "lib", id.fullName);
+    var sourcePath = join(rootDir, "lib", id.description);

[nweiz, 2012/05/18 00:08:24]

This should validate that id.description is a string, as should packageName.
Maybe Source should have a validateDescription method that's automatically
called before calling packageName or install?

[Bob Nystrom, 2012/05/18 20:02:38]

Good idea. Done.

     return exists(sourcePath).chain((exists) {
       if (!exists) return new Future<bool>.immediate(false);
       return createSymlink(sourcePath, destPath).transform((_) => true);
     });
   }
+
+  String packageName(PackageId id) => id.description;
 }