From: "Jan E." <lists@...>
Date: 2012-05-18T12:20:50+09:00
Subject: Re: what is going wrong here? The case of the noob not understanding initialize

This looks good. :-)

Since you already said that the character tests follow the same pattern, 
you might wanna think about writing only one generalized method. For 
example, you could put the character sets and the corresponding "scores" 
in an array and then let a method iterate over it. You don't even have 
to write the actual characters down but use regular expressions instead:

/\p{Lower}/

This regular expression matches any string with a lower case letter (of 
any language) in it. If you only want the latin letters from a to z, you 
can instead use the pattern

/[a-z]/

This narrows the test down to one line: password =~ pattern

As a complete example:


#------------------------------------------
class Entropy

  # the scores are just made up
  CHARACTER_SCORES = {
    # special characters
    # = printable ASCII characters which are not alphanumeric
    /[\p{ASCII}&&\p{Graph}&&\p{^Alnum}]/ => 11,
    # uppercase letters
    /[A-Z]/ => 22,
    # lowercase letter
    /[a-z]/ => 33,
    # digits
    /[0-9]/ => 44
  }

  def test_characters password
    CHARACTER_SCORES.inject 0 do |sum, (pattern, score)|
      password =~ pattern ? sum + score : sum
    end
  end

end
#------------------------------------------


By the way, most of the time you don't need lowlevel structures like the 
while statement. Ruby has a lot of iterators which do the same thing in 
a lot less lines.

For example, you could rewrite the dictionary method to this:


#------------------------------------------
def contains_dictionary_word?(password)
  entropy_bits = 0
  passed_dictionary_test =
    File.foreach("#{RELATIVEPATH}/data/dictionary").any? do |line|
      password.include? line.chop
    end
  entropy_bits = 6 if passed_dictionary_test and password.length > 4
  return entropy_bits
end
#------------------------------------------


The "while gets" is replaced with "File.foreach". And the "break false" 
is replaced with the "any?" iterator.

On last thing: You should be careful with method names. A method called 
"contains_dictionary_word?" looks all like it returns either true or 
false. It it returns a score instead, this may lead to confusion. So I'd 
rather call it "test_dictionary" or so.

-- 
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