Make VersionRange implement Comparable.

lib/src/version.dart

Index: lib/src/version.dart
diff --git a/lib/src/version.dart b/lib/src/version.dart
index 98722897cb39e2dd3dde17b6b1c54fda13e47fbd..f2662b9aaada76cec70f5f63ccc9cebfa0c7dcaa 100644
--- a/lib/src/version.dart
+++ b/lib/src/version.dart
@@ -14,7 +14,7 @@ import 'version_range.dart';
 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);
 
@@ -267,22 +267,26 @@ class Version implements Comparable<Version>, VersionConstraint, VersionRange {
     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);
-
-    // 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;
-
-    // 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);
+  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;
+
+      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);
+    } else {
+      return -other.compareTo(this);
+    }
   }
 
   String toString() => _text;