embed_code.rb

require 'cgi'

source = ARGV.shift
exit if ! source

def header(name)
  h = '<pre class="code"><code>' + "(#{File.basename(name)})"
  puts h
end

def footer
  puts '</code></pre>'
end

def scale(n)
  Math::log10(n).floor + 1
end

count = 1
lines = IO.readlines(source)
format = "%#{scale(lines.length)}d"

header(source)
lines.each do |code|
  code = CGI::escapeHTML(code.chomp)
  numbering = format % count
  STDOUT.puts "#{numbering}: #{code}"
  count += 1
end
footer