properly escaping regex terms

lib/term-extract.rb

@@ -107,7 +107,7 @@ def extract(content)
     if @collapse_terms
       terms.each_key do |term1|
         terms.each_key do |term2|
-          terms.delete(term2) if term1.length > term2.length && (term1 =~ /[^A-Za-z0-9]#{clean_regex(term2)}$/ || term1 =~ /^#{clean_regex(term2)}[^A-Za-z0-9]/)
+          terms.delete(term2) if term1.length > term2.length && (term1 =~ /[^A-Za-z0-9]#{Regexp.escape(term2)}$/ || term1 =~ /^#{Regexp.escape(term2)}[^A-Za-z0-9]/)
         end
       end
     end
@@ -120,10 +120,6 @@ def extract(content)
   end
 
   protected  
-  def clean_regex(term)
-    term.gsub(/([\*\+\.\?])/, '\\\\\1')
-  end
-
   def preprocess_tags(pos)
     # Add in full stops to tag list to allow multiterms to work
     tags = []