From df6feab34613c455e45404d443dd9895a128eac1 Mon Sep 17 00:00:00 2001
From: Nathan Sobo <nathan@github.com>
Date: Wed, 24 Apr 2013 16:19:59 -0600
Subject: [PATCH] Add Range.compare

---
 spec/app/range-spec.coffee |  8 ++++++++
 src/app/range.coffee       | 17 +++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/spec/app/range-spec.coffee b/spec/app/range-spec.coffee
index c73111ace..24460a064 100644
--- a/spec/app/range-spec.coffee
+++ b/spec/app/range-spec.coffee
@@ -33,6 +33,14 @@ describe "Range", ->
       expect(new Range([2, 1], [3, 10]).union(new Range([2, 5], [3, 1]))).toEqual [[2, 1], [3, 10]]
       expect(new Range([2, 5], [3, 1]).union(new Range([2, 1], [3, 10]))).toEqual [[2, 1], [3, 10]]
 
+  describe ".compare(otherRange)", ->
+    it "sorts earlier ranges first, and larger ranges first if both ranges start at the same place", ->
+      expect(new Range([1, 1], [2, 10]).compare(new Range([2, 1], [3, 10]))).toBe -1
+      expect(new Range([2, 1], [3, 10]).compare(new Range([1, 1], [2, 10]))).toBe 1
+      expect(new Range([1, 1], [3, 10]).compare(new Range([1, 1], [2, 10]))).toBe -1
+      expect(new Range([1, 1], [2, 10]).compare(new Range([1, 1], [3, 10]))).toBe 1
+      expect(new Range([1, 1], [3, 10]).compare(new Range([1, 1], [3, 10]))).toBe 0
+
   describe ".translate(startPoint, endPoint)", ->
     it "returns a range translates by the specified start and end points", ->
       expect(new Range([1, 1], [2, 10]).translate([1])).toEqual [[2, 1], [3, 10]]
diff --git a/src/app/range.coffee b/src/app/range.coffee
index 72e1ede1a..d4e7f2ba2 100644
--- a/src/app/range.coffee
+++ b/src/app/range.coffee
@@ -71,6 +71,23 @@ class Range
 
     other.start.isEqual(@start) and other.end.isEqual(@end)
 
+  # Returns an integer (-1, 0, 1) indicating whether this range is less than, equal,
+  # or greater than the given range when sorting.
+  #
+  # Ranges that start earlier are considered "less than" ranges that start later.
+  # If ranges start at the same location, the larger range sorts before the smaller
+  # range.
+  #
+  # other - A {Range} to compare against.
+  #
+  # Returns a {Number}, either -1, 0, or 1.
+  compare: (other) ->
+    other = Range.fromObject(other)
+    if value = @start.compare(other.start)
+      value
+    else
+      other.end.compare(@end)
+
   # Public: Identifies if the `Range` is on the same line.
   #
   # In other words, if `start.row` is equal to `end.row`.