Make VersionRange implement Comparable.

lib/src/version.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:math' as math;
 
 import 'package:collection/collection.dart';
 
 import 'patterns.dart';
 import 'version_constraint.dart';
 import 'version_range.dart';
 
 /// The equality operator to use for comparing version components.
 final _equality = const IterableEquality();
 
 /// A parsed semantic version number.
-class Version implements Comparable<Version>, VersionConstraint, VersionRange {
+class Version implements VersionConstraint, VersionRange {

[Bob Nystrom, 2016/06/03 16:18:03]

Can this implement Comparable<VersionRange>?

[nweiz, 2016/06/06 22:27:46]

It already does, transitively through VersionRange.

   /// No released version: i.e. "0.0.0".
   static Version get none => new Version(0, 0, 0);
 
   /// Compares [a] and [b] to see which takes priority over the other.
   ///
   /// Returns `1` if [a] takes priority over [b] and `-1` if vice versa. If
   /// [a] and [b] are equivalent, returns `0`.
   ///
   /// Unlike [compareTo], which *orders* versions, this determines which
   /// version a user is likely to prefer. In particular, it prioritizes
@@ skipping 232 matching lines @@
       if (other.max == this) {
         return new VersionRange(
             min: other.min, max: other.max,
             includeMin: other.includeMin, includeMax: true);
       }
     }
 
     return new VersionConstraint.unionOf([this, other]);
   }
 
-  int compareTo(Version other) {
-    if (major != other.major) return major.compareTo(other.major);
-    if (minor != other.minor) return minor.compareTo(other.minor);
-    if (patch != other.patch) return patch.compareTo(other.patch);
+  int compareTo(VersionRange other) {
+    if (other is Version) {

[Bob Nystrom, 2016/06/03 16:18:03]

Might be a bit simpler to do the negative test:

if (other is! Version) return -other.compareTo(this);

[nweiz, 2016/06/06 22:27:46]

https://github.com/dart-lang/sdk/issues/25565 :(

+      if (major != other.major) return major.compareTo(other.major);
+      if (minor != other.minor) return minor.compareTo(other.minor);
+      if (patch != other.patch) return patch.compareTo(other.patch);
 
-    // Pre-releases always come before no pre-release string.
-    if (!isPreRelease && other.isPreRelease) return 1;
-    if (!other.isPreRelease && isPreRelease) return -1;
+      // Pre-releases always come before no pre-release string.
+      if (!isPreRelease && other.isPreRelease) return 1;
+      if (!other.isPreRelease && isPreRelease) return -1;
 
-    var comparison = _compareLists(preRelease, other.preRelease);
-    if (comparison != 0) return comparison;
+      var comparison = _compareLists(preRelease, other.preRelease);
+      if (comparison != 0) return comparison;
 
-    // Builds always come after no build string.
-    if (build.isEmpty && other.build.isNotEmpty) return -1;
-    if (other.build.isEmpty && build.isNotEmpty) return 1;
-    return _compareLists(build, other.build);
+      // Builds always come after no build string.
+      if (build.isEmpty && other.build.isNotEmpty) return -1;
+      if (other.build.isEmpty && build.isNotEmpty) return 1;
+      return _compareLists(build, other.build);
+    } else {
+      return -other.compareTo(this);
+    }
   }
 
   String toString() => _text;
 
   /// Compares a dot-separated component of two versions.
   ///
   /// This is used for the pre-release and build version parts. This follows
   /// Rule 12 of the Semantic Versioning spec (v2.0.0-rc.1).
   int _compareLists(List a, List b) {
     for (var i = 0; i < math.max(a.length, b.length); i++) {
@@ skipping 22 matching lines @@
           // Compare two strings.
           return aPart.compareTo(bPart);
         }
       }
     }
 
     // The lists are entirely equal.
     return 0;
   }
 }