Is it acceptable having parameter in class constructor?

Question

a rubygem I'm writing and that is useful for counting word occurrences in a text, I choose to put 3 parameters in class constructor.

The code is working, but I want to refactor it for niceness. In your experience, it's easier to read/mantain/use as API a class with a constructor with no params and a lot of setters/getters method or a code like this one, with all the params in the constructor?

TIA

Paolo

def initialize(filename, words, hide_list)

  if ! filename.nil?
    @filename = filename
    @occurrences = read
  else
    @filename = STDIN
    @occurrences = feed
  end

  @hide_list = hide_list
  @sorted = Array(occurrences).sort { |one, two| -(one[1] <=> two[1]) }
  @words = words

end

Answer 1

You could do it the rails way, where options are given in a hash:

def initialize(filename = nil, options = {})
  @hide_list = options[:hide_list]
  @words = options[:words]

  if filename
    @filename = filename
    @occurrences = read
  else
    @filename = STDIN
    @occurrences = feed
  end

  @sorted = Array(occurrences).sort { |one, two| -(one[1] <=> two[1]) }

end

Then you can call it like this:

WC.new "file.txt", :hide_list => %w(a the to), :words => %w(some words here)

or this:

wc = WC.new
wc.hide_list = %w(a the is)
wc.words = %w(some words here)