From: Robert Klemme <shortcutter@...>
Date: 2009-08-24T23:44:23+09:00
Subject: Re: 1.8.7 String#lines keeps new-line chars (say it ain't so in 1.9)

2009/8/24 Trans <transfire@gmail.com>:
>
>
> On Aug 24, 9:17 am, Brian Candler <b.cand...@pobox.com> wrote:
>> Thomas Sawyer wrote:
>> > To me returning the newline code with #lines would be like returning
>> > the spaces for a method #words. Eg.
>>
>> >   "show it\nto me".words => ["show ", "it\n", "to ", "me "]
>>
>> ...except there is no built-in method 'words' so you can't accuse it of
>> being inconsistent :-)
>
> ok ;) ...just making an analogy.
>
>> Some people would want lines with trailing whitespace stripped as well
>> as terminators. Some people would want leading whitespace stripped too.
>> I don't think you can please everyone, so IMO the most flexible and
>> consistent approach is to give the line complete with its terminator,
>> and let the user apply whatever post-processing they like.
>
> Sure, but at that point we are moving into a realm of narrower
> usecases. I believe the short, more concise method name should go to
> the most frequent use. I have no definitive statistics, but I'd wager
> that split("\n") is by far the more common case. Based on that, I'd
> rather see the current def be called something else, like #newlines or
> #rawlines. But Ruby is ultimately Matz' baby so maybe his more common
> use is otherwise.

I don't think it is a good idea to change the default behavior.  If
you frequently need line endings stripped, you can always define your
own method for this, for example:

class LineEnum
  include Enumerable

  def initialize(obj, meth = case obj
                             when String, IO then :each_line
                             else :each
                             end)
    @obj = obj
    @meth = meth
  end

  def each
    @obj.send(@meth) do |elem|
      elem.chomp!
      yield elem
    end

    self
  end
end

$ irb19 -r lineenum.rb
Ruby version 1.9.1
irb(main):001:0> s = "foo\nbar\n"
=> "foo\nbar\n"
irb(main):002:0> se = LineEnum.new s
=> #<LineEnum:0x10169bc0 @obj="foo\nbar\n", @meth=:each_line>
irb(main):003:0>  se.each {|l| p l}
"foo"
"bar"
=> #<LineEnum:0x10169bc0 @obj="foo\nbar\n", @meth=:each_line>
irb(main):004:0>

We could also extend Enumerator to honor blocks passed to them so we could do

$stdin.to_enum(:each_line) {|l| l.strip!}.each do |line|
  p line # no \n present
end

But frankly, I'd rather just add a "line.chomp!" to my block body and
be done. :-)

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/