Add VersionConstraint.difference().

Add VersionConstraint.difference().

See dart-lang/pub#912

R=rnystrom@google.com

Committed: https://github.com/dart-lang/pub_semver/commit/17838f3fae618acae4bbda756484f15a0c89bcb7

[Bob Nystrom, 2016-06-08 22:51:06]

LGTM!

https://codereview.chromium.org/2045803002/diff/1/lib/src/utils.dart
File lib/src/utils.dart (right):

https://codereview.chromium.org/2045803002/diff/1/lib/src/utils.dart#newcode16
lib/src/utils.dart:16: /// Returns whether [range1] allows lower versions than
[range2].
Do you think it's worth hanging these methods off VersionRange, or do we not
want to publicly support them?

https://codereview.chromium.org/2045803002/diff/1/lib/src/utils.dart#newcode41
lib/src/utils.dart:41: if (range1.max == null || range2.min == null) return
false;
Is it possible for range1 to be empty? If so, is it strictly before all other
ranges?

https://codereview.chromium.org/2045803002/diff/1/lib/src/version_constraint....
File lib/src/version_constraint.dart (right):

https://codereview.chromium.org/2045803002/diff/1/lib/src/version_constraint....
lib/src/version_constraint.dart:240: /// Creates a new [VersionConstraint] that
allows [Version]s allowed by this
Technically, these don't always create *new* constraints. How about just
"Returns a [VersionConstraint]..."

[nweiz, 2016-06-08 23:39:02]

https://codereview.chromium.org/2045803002/diff/1/lib/src/utils.dart
File lib/src/utils.dart (right):

https://codereview.chromium.org/2045803002/diff/1/lib/src/utils.dart#newcode16
lib/src/utils.dart:16: /// Returns whether [range1] allows lower versions than
[range2].
On 2016/06/08 22:51:06, Bob Nystrom wrote:
> Do you think it's worth hanging these methods off VersionRange, or do we not
> want to publicly support them?

I don't think they're general-purpose enough to publicly support. They're here
more or less just for implementation reasons; they're the most efficient way
I've found of writing the public methods.

https://codereview.chromium.org/2045803002/diff/1/lib/src/utils.dart#newcode41
lib/src/utils.dart:41: if (range1.max == null || range2.min == null) return
false;
On 2016/06/08 22:51:06, Bob Nystrom wrote:
> Is it possible for range1 to be empty? If so, is it strictly before all other
> ranges?

We generally assume that empty constraints are only ever represented as
VersionRange.empty, in which case they won't make it here since they don't
actually implement VersionRange.

https://codereview.chromium.org/2045803002/diff/1/lib/src/version_constraint....
File lib/src/version_constraint.dart (right):

https://codereview.chromium.org/2045803002/diff/1/lib/src/version_constraint....
lib/src/version_constraint.dart:240: /// Creates a new [VersionConstraint] that
allows [Version]s allowed by this
On 2016/06/08 22:51:06, Bob Nystrom wrote:
> Technically, these don't always create *new* constraints. How about just
> "Returns a [VersionConstraint]..."

Done.

[nweiz, 2016-06-08 23:41:44]

Code review changes

[nweiz, 2016-06-08 23:41:54]

Description was changed from

==========
Add VersionConstraint.difference().

See dart-lang/pub#912

R=rnystrom@google.com
==========

to

==========
Add VersionConstraint.difference().

See dart-lang/pub#912

R=rnystrom@google.com

Committed:
https://github.com/dart-lang/pub_semver/commit/17838f3fae618acae4bbda756484f1...
==========

[nweiz, 2016-06-08 23:41:56]

Committed patchset #2 (id:20001) manually as
17838f3fae618acae4bbda756484f15a0c89bcb7 (presubmit successful).