#custom filters for Octopress
 
 module OctopressFilters

   # Used on the blog index to split posts on the <!--more--> marker

   def excerpt(input)

     if input.index(/<!--\s*more\s*-->/i)
       input.split(/<!--\s*more\s*-->/i)[0]

     else
       input
     end
   end

 
   # Summary is used on the Archive pages to return the first block of content from a post.
   def summary(input)
     if input.index(/\n\n/)
       input.split(/\n\n/)[0]

     else
       input
     end
   end

 
   # Replaces relative urls with full urls

   def expand_urls(input, url='')
     url ||= '/'

     input.gsub /(\s+(href|src)\s*=\s*["|']{1})(\/[^\"'>]+)/ do
       $1+url+$3
     end
   end

   # Removes trailing forward slash from a string for easily appending url segments
   def strip_slash(input)
     if input =~ /(.+)\/$|^\/$/
       input = $1
     end
     input
   end
 
   # Returns a url without the protocol (http://)
   def shorthand_url(input)

     input.gsub /(https?:\/\/)(\S+)/ do

       $2
     end
   end

 
   # replaces primes with smartquotes using RubyPants

   def smart_quotes(input)
     require 'rubypants'
     RubyPants.new(input).to_html
   end

 
   # Returns a title cased string based on John Gruber's title case http://daringfireball.net/2008/08/title_case_update

   def titlecase(input)
     input.titlecase
   end

 
   # Returns a datetime if the input is a string

   def datetime(date)

     if date.class == String
       date = Time.parse(date)
     end

     date
   end

 
   # Returns an ordidinal date eg July 22 2007 -> July 22nd 2007

   def ordinalize(date)
     date = datetime(date)

     "#{date.strftime('%b')} #{ordinal(date.strftime('%e').to_i)}, #{date.strftime('%Y')}"

   end

 
   # Returns an ordinal number. 13 -> 13th, 21 -> 21st etc.

   def ordinal(number)
     if (11..13).include?(number.to_i % 100)
       "#{number}<span>th</span>"
     else
       case number.to_i % 10
       when 1; "#{number}<span>st</span>"

       when 2; "#{number}<span>nd</span>"

       when 3; "#{number}<span>rd</span>"
       else    "#{number}<span>th</span>"
       end
     end
   end
 end
 Liquid::Template.register_filter OctopressFilters