How to treat single newline as real line break in PHP Markdown?

Question

I was reading http://github.github.com/github-flavored-markdown/

I would like to implement that \"Newline modification\" in PHP Markdown:

Best I could think of

Answer 1

As an ad-hoc script you can just run this on your string before running the markdown script

$text = preg_replace_callback("/^[\w\<][^\n]*\n+/msU",function($x){
$x = $x[0];
$x = preg_match("/\n{2}/",$x,$match)? $x: trim($x)."  \r\n";
return $x;
},$text);

$my_html = Markdown($text);

Based on the github flavored markdown

text.gsub!(/^[\w\<][^\n]*\n+/) do |x|
    x =~ /\n{2}/ ? x : (x.strip!; x << "  \n")
end

P.S. I'm not the best at regex and I don't know what programming language github uses so I improvised