I am currently readying Trackplace for the world. Trackplace is a simple web app that can help you track and share things. It's been a personal project/hobby of mine for a while and it'll be fun to see it out the wild soon...

Anyways... the site uses Markdown via the BlueCloth gem to markup portions of the site. While I personally love Markdown, almost all my friends who are beta-testing the site complain that "the site bunches up all my lines" or "I can't make a new line".

This is due to Markdown's choice of paragraph implementation:

A paragraph is simply one or more consecutive lines of text, separated by one or more blank lines.

The implication of the “one or more consecutive lines of text” rule is that Markdown supports “hard-wrapped” text paragraphs. This differs significantly from most other text-to-HTML formatters (including Movable Type’s “Convert Line Breaks” option) which translate every line break character in a paragraph into a <br /> tag.

Yet I needed Markdown to respect a "\n" from the user...

As Paul Graham said:

Part of what software has to do is explain itself. So to write good software you have to understand how little users understand. They're going to walk up to the software with no preparation, and it had better do what they guess it will, because they're not going to read the manual.

I first started playing with regular expressions to post-process the html from BlueCloth. But that got real hairy real fast. Just when I thought all was lost... Hpricot turns up to save the day. Hpricot really is one of my new favorite tools - thanks Why! Basically I only wanted to insert hard breaks inside paragraphs and so a simple helper does the trick.

application_helper.rb

require 'hpricot'
module ApplicationHelper

  def md(str)
    return '' if str.blank?

    # --- [ add hard line breaks ] ---
    returning html = BlueCloth.new(str).to_html do
      Hpricot(html).search("//p").each do |p|
        html.sub!(p.to_s, p.to_s.gsub(%r{\n+}, "\n<br/>\n"))
      end
    end
  end

end