Add a CanonicalizedMap class to pkg/collection.

pkg/collection/lib/collection.dart

Index: pkg/collection/lib/collection.dart
diff --git a/pkg/collection/lib/collection.dart b/pkg/collection/lib/collection.dart
index d640071630f6d47c782ef4da53caa3a8ab45cd34..d24dd39340b71344d0ad28e5e3b5e7a39559308f 100644
--- a/pkg/collection/lib/collection.dart
+++ b/pkg/collection/lib/collection.dart
@@ -21,4 +21,5 @@ export "algorithms.dart";
 export "equality.dart";
 export "iterable_zip.dart";
 export "priority_queue.dart";
+export "src/canonicalized_map.dart";

[Lasse Reichstein Nielsen, 2014/06/27 06:57:47]

This makes CanonicalizedMap *only* available by importing package:collection.
The other libraries can be imported individually as well (it's deliberate that
they are not in the src directory).

Either move canonicalized_map to lib/ or just make it part of wrappers.dart (I
think I prefer the latter, just make it a part instead of a library, and part it
from wrappers.dart)

[nweiz, 2014/06/30 20:37:46]

This is contrary to the standard package layout; I had assumed the current
layout of this package was a holdover from before the standards were solidified.

Since we have show/hide, there's not really much utility in having a large
number of top-level libraries except when those libraries use incompatible core
libraries (e.g. dart:io vs dart:html) or when those libraries are intended to be
imported with different prefixes (e.g. json_rpc_2's error_codes library).
I can do this if you want, but please consider moving this package towards the
standard layout. The less idiosyncratic it is the easier it will be for users to
understand it.

[Lasse Reichstein Nielsen, 2014/07/01 09:18:14]

I don't see where the standard layout
(https://www.dartlang.org/tools/pub/package-layout.html#public-libraries)
restricts the public libraries only to those that are incompatible in some way.
I thought it was a completely valid choice to have a package containing several
individual libraries.

The individual libraries in package:collection can be quite large (even if not
all are), so we wanted to be able to import only the type of functionality that
was needed - it's not viable to "show", e.g., everything currently in
equality.dart

So, unless there is a general agreement that having separate top-level libraries
grouped by subject, not by requirements, is deprecated, I think I'll prefer to
keep it that way.

I still think I'd want canonicalized-map to be in the wrappers library, so you
can keep it in source and export it from wrappers instead (or make it a part
instead of a library).

[nweiz, 2014/07/01 21:21:44]

That page just lists the hard requirements and strong suggestions. This is more
of a community convention that's been adopted by most packages.
Done.

 export "wrappers.dart";