class Sinatra::Base

def inline_templates=(file=nil)

when no file is specified.
Load embeded templates from the file; uses the caller's __FILE__
def inline_templates=(file=nil)
  file = (file.nil? || file == true) ? (caller_files.first || File.expand_path($0)) : file
  begin
    io = ::IO.respond_to?(:binread) ? ::IO.binread(file) : ::IO.read(file)
    app, data = io.gsub("\r\n", "\n").split(/^__END__$/, 2)
  rescue Errno::ENOENT
    app, data = nil
  end
  if data
    if app and app =~ /([^\n]*\n)?#[^\n]*coding: *(\S+)/m
      encoding = $2
    else
      encoding = settings.default_encoding
    end
    lines = app.count("\n") + 1
    template = nil
    force_encoding data, encoding
    data.each_line do |line|
      lines += 1
      if line =~ /^@@\s*(.*\S)\s*$/
        template = force_encoding('', encoding)
        templates[$1.to_sym] = [template, file, lines]
      elsif template
        template << line
      end
    end
  end
end