add abbrev to SortedArray

lib/sorted_containers/sorted_array.rb

@@ -160,6 +160,26 @@ def slice(*args)
     alias [] slice
     # rubocop:enable Metrics/MethodLength
 
+    # Calculates the set of unambiguous abbreviations for the strings in +self+.
+    #
+    #   require 'abbrev'
+    #   SortedArray.new(%w{ car cone }).abbrev
+    #   #=> {"car"=>"car", "ca"=>"car", "cone"=>"cone", "con"=>"cone", "co"=>"cone"}
+    #
+    # The optional +pattern+ parameter is a pattern or a string. Only input
+    # strings that match the pattern or start with the string are included in the
+    # output hash.
+    #
+    #   SortedArray.new(%w{ fast boat day }).abbrev(/^.a/)
+    #   #=> {"fast"=>"fast", "fas"=>"fast", "fa"=>"fast", "day"=>"day", "da"=>"day"}
+    #
+    # @param pattern [Regexp, String] The pattern to match.
+    # @return [Hash] The set of unambiguous abbreviations.
+    # See also Abbrev.abbrev
+    def abbrev(pattern = nil)
+      to_a.abbrev(pattern)
+    end
+
     # Returns a string representation of the sorted array.
     #
     # @return [String] A string representation of the sorted array.

spec/sorted_array_spec.rb

@@ -229,6 +229,39 @@
     end
   end
 
+  describe "abbrev" do
+    require "abbrev"
+
+    it "should return the abbreviations of the array" do
+      basic_array = %w[car cone]
+      array = SortedContainers::SortedArray.new(basic_array)
+      expect(array.abbrev).to eq(basic_array.abbrev)
+    end
+
+    it "should only return abbreviations of strings that match the given pattern" do
+      basic_array = %w[fast boat day]
+      array = SortedContainers::SortedArray.new(basic_array)
+      expect(array.abbrev(/^.a/)).to eq(basic_array.abbrev(/^.a/))
+    end
+
+    it "should only return abbreviantions of strings that start with the given string" do
+      basic_array = %w[fast boat day]
+      array = SortedContainers::SortedArray.new(basic_array)
+      expect(array.abbrev("da")).to eq(basic_array.abbrev("da"))
+    end
+
+    it "should return an empty hash if there are no matches" do
+      basic_array = %w[fast boat day]
+      array = SortedContainers::SortedArray.new(basic_array)
+      expect(array.abbrev("zz")).to eq(basic_array.abbrev("zz"))
+    end
+
+    it "should return an empty hash if the array is empty" do
+      array = SortedContainers::SortedArray.new
+      expect(array.abbrev).to eq({})
+    end
+  end
+
   describe "load_factor" do
     it "should set the load factor to the provided value" do
       array = SortedContainers::SortedArray.new([], load_factor: 100)