require 'pathname'

class Pathname
  # create a new Pathname object for path, any backslashes are converted to /, 
  # if Pathname object is passed in then returns this existing pathname object
  def self.for_path(path)
    return path if path.is_a? Pathname
    Pathname.new(path.gsub('\\','/'))
  end

  # return the concatenated path, cleaning up any backslashes, ignores nulls or empty pathnames
  def self.join(*args)
    pathnames = args.collect { |a| Pathname.for_path(a) }
    pathnames.inject { |fullpath, p| self.safe_concat(fullpath, p) }
  end

  # prepends a pathname to existing, ignores nulls or empty pathnames
  def self.safe_concat(prepend_pn, pathname)
    return nil if ((prepend_pn.nil? ||  prepend_pn.to_s.empty?) && (pathname.nil? || pathname.to_s.empty?)) #both are nil or empty
    return prepend_pn if (pathname.nil? || pathname.to_s.empty?)
    return pathname if (prepend_pn.nil? || prepend_pn.to_s.empty?)
    prepend_pn+pathname
  end

  # return the path string without the extension
  def path_no_ext
    dirname = self.dirname
    ext = self.extname
    base = self.basename(ext)
    presult = (dirname.to_s.empty?) ? base : dirname+base
    presult.to_s
  end
end