Add a tiny filter. (#277)

* Add a tiny filter.

* As suggested by @inukshuk, use span with tiny CSS.

* Add quotation marks.

features/filter.feature

@@ -584,3 +584,28 @@ Feature: BibTeX
     And the "_site/scholar.html" file should exist
     And I should see "This is &#0174 to me." in "_site/scholar.html"
 
+  @tags @tiny
+  Scenario: LaTeX tiny as HTML registered symbol
+    Given I have a scholar configuration with:
+      | key    | value             |
+      | source | ./_bibliography   |
+    And I have the following BibTeX filters:
+      | tiny |
+    And I have a "_bibliography" directory
+    And I have a file "_bibliography/references.bib":
+      """
+      @misc{pickaxe,
+        title     = {This is \tiny{i is tiny} to me.}
+      }
+      """
+    And I have a page "scholar.html":
+      """
+      ---
+      ---
+      {% bibliography %}
+      """
+    When I run jekyll
+    Then the _site directory should exist
+    And the "_site/scholar.html" file should exist
+    And I should see "This is <span class="tiny">i is tiny</span> to me." in "_site/scholar.html"
+

lib/jekyll/scholar.rb

@@ -28,3 +28,4 @@
 require 'jekyll/scholar/plugins/textit'
 require 'jekyll/scholar/plugins/lowercase'
 require 'jekyll/scholar/plugins/textregistered'
+require 'jekyll/scholar/plugins/tiny'

lib/jekyll/scholar/defaults.rb

@@ -36,7 +36,7 @@ class Scholar
       'repository_file_delimiter' => '.',
 
       'bibtex_options'         => { :strip => false, :parse_months => true },
-      'bibtex_filters'         => [ :smallcaps, :superscript, :italics, :textit, :lowercase, :textregistered, :latex ],
+      'bibtex_filters'         => [ :smallcaps, :superscript, :italics, :textit, :lowercase, :textregistered, :tiny, :latex ],
       'bibtex_skip_fields'     => [ :abstract, :month_numeric ],
       'bibtex_quotes'          => ['{', '}'],
 

lib/jekyll/scholar/plugins/tiny.rb

@@ -0,0 +1,13 @@
+module Jekyll
+  class Scholar
+    class Tiny < BibTeX::Filter
+      def apply(value)
+        # Use of \g<1> pattern back-reference to allow for capturing nested {} groups.
+        # The first (outermost) capture of $1 is used.
+        value.to_s.gsub(/\\tiny(\{(?:[^{}]|\g<1>)*\})/) {
+          "<span class="tiny">#{$1[1..-2]}</span>"
+        }
+      end
+    end
+  end
+end