Add locator label option

See #147

features/citation.feature

@@ -235,6 +235,33 @@ Feature: Citations
     And the "_site/scholar.html" file should exist
     And I should see "Matsumoto, 2008, pp. 2-3; Shaughnessy, 2013, pp. 23 & 42" in "_site/scholar.html"
 
+  @tags @cite @locator @label
+  Scenario: Citations with locator labels
+    Given I have a scholar configuration with:
+      | key          | value             |
+      | source       | ./_bibliography   |
+      | bibliography | my_references     |
+    And I have a "_bibliography" directory
+    And I have a file "_bibliography/my_references.bib":
+      """
+      @book{ruby,
+        title     = {The Ruby Programming Language},
+        author    = {Flanagan, David and Matsumoto, Yukihiro},
+        year      = {2008},
+        publisher = {O'Reilly Media}
+      }
+      """
+    And I have a page "scholar.html":
+      """
+      ---
+      ---
+      {% cite ruby --label chapter --locator 3 %}
+      """
+    When I run jekyll
+    Then the _site directory should exist
+    And the "_site/scholar.html" file should exist
+    And I should see "Flanagan & Matsumoto, 2008, chap. 3" in "_site/scholar.html"
+
   @tags @cite @citation_number
   Scenario: Multiple citations using citation numbers
     Given I have a scholar configuration with:

lib/jekyll/scholar/utilities.rb

@@ -18,7 +18,8 @@ module Jekyll
     module Utilities
 
 
-      attr_reader :config, :site, :context, :prefix, :text, :offset, :max
+      attr_reader :config, :site, :context,
+        :prefix, :text, :offset, :max, :label
 
 
 
@@ -69,6 +70,10 @@ module Jekyll
             locators << locator
           end
 
+          opts.on('-L', '--label LABEL') do |label|
+            @label = label
+          end
+
           opts.on('-o', '--offset OFFSET') do |offset|
             @offset = offset.to_i
           end
@@ -98,7 +103,7 @@ module Jekyll
           end
         end
 
-        argv = arguments.split(/(\B-[cCfqptTsgGOlomA]|\B--(?:cited(_in_order)?|file|query|prefix|text|style|group_(?:by|order)|type_order|template|locator|offset|max|suppress_author|))/)
+        argv = arguments.split(/(\B-[cCfqptTsgGOlLomA]|\B--(?:cited(_in_order)?|file|query|prefix|text|style|group_(?:by|order)|type_order|template|locator|label|offset|max|suppress_author|))/)
 
         parser.parse argv.map(&:strip).reject(&:empty?)
       end
@@ -569,6 +574,7 @@ module Jekyll
 
           item = citation_item_for entry, citation_number(entry.key)
           item.locator = locator
+          item.label = label unless label.nil?
 
           item
         }, STYLES[style].citation