add Book::Bib for bib.re

lib/review/book/base.rb

@@ -9,6 +9,7 @@
 #
 require 'review/configure'
 require 'review/catalog'
+require 'review/book/bib'
 
 module ReVIEW
   module Book
@@ -124,7 +125,7 @@ def create_chapter_index
 
       def generate_indexes
         if bib_exist?
-          bib = ReVIEW::Book::BookUnit.new(file_content: bib_content, book: self)
+          bib = ReVIEW::Book::Bib.new(file_content: bib_content, book: self)
           bib.generate_indexes(use_bib: true)
           @bibpaper_index = bib.bibpaper_index
         end

lib/review/book/bib.rb

@@ -0,0 +1,21 @@
+#
+# Copyright (c) 2009-2020 Minero Aoki, Kenshi Muto
+#
+# This program is free software.
+# You can distribute or modify this program under the terms of
+# the GNU LGPL, Lesser General Public License version 2.1.
+# For details of the GNU LGPL, see the file "COPYING".
+#
+require 'review/book/book_unit'
+require 'review/lineinput'
+require 'review/preprocessor'
+
+module ReVIEW
+  module Book
+    class Bib < BookUnit
+      def number
+        nil
+      end
+    end
+  end
+end

lib/review/book/book_unit.rb

@@ -63,10 +63,6 @@ def generate_indexes(use_bib: false)
         end
       end
 
-      def number
-        nil
-      end
-
       def dirname
         @path && File.dirname(@path)
       end