From: "nobu (Nobuyoshi Nakada)" <nobu@...>
Date: 2012-10-01T10:31:05+09:00
Subject: [ruby-core:47760] [ruby-trunk - Feature #7091] Object#puts_to


Issue #7091 has been updated by nobu (Nobuyoshi Nakada).


=begin
 readlines.sort.map{...}.select{...}.display($stderr) 
=end

----------------------------------------
Feature #7091: Object#puts_to
https://bugs.ruby-lang.org/issues/7091#change-29815

Author: prijutme4ty (Ilya Vorontsov)
Status: Rejected
Priority: Normal
Assignee: 
Category: 
Target version: 


I suggest a new method Object#puts_to(io_or_filename) (or BasicObject#puts_to)

It's usual that one-two-three-line scripts have big chains like
readlines.sort.map{...}.select{...} and so on and after you wrote such a monstruous expression to process input, you understand that you should output it. If script's written offhand, you wouldn't create a new variable just to use it at next line, so you write smth like

puts( readlines.sort.map{...}.select{...} )
or at least
readlines.sort.map{...}.select{...}.tap{|x| puts x}

It looks ugly and isn't readable. Thing get even worse when you are writing object info a file:
File.open('file.txt','w'){|f| f.puts( readlines.sort.map{...}.select{...} ) }

I write such constructions many times a day, just because my scripts are usually used once or twice and I can't waste my time to make this more clear.
Instead of such a pasta-code, one can make smth like this:

readlines.sort.map{...}.select{...}.puts_to
readlines.sort.map{...}.select{...}.puts_to($stderr)
readlines.sort.map{...}.select{...}.puts_to('')
readlines.sort.map{...}.select{...}.puts_to(filename:'', append:true)

Implementation can be smth like this:

class Object
  def puts_to(io_or_filename = $stdout)
    if io_or_filename.respond_to?(:puts)
      io_or_filename.puts(self)
    else
      case io_or_filename
      when String
        File.open(io_or_filename,'w'){|f| f.puts self }
      when Hash
        File.open(io_or_filename[:filename],io_or_filename[:append] ? 'a' : 'w'){|f| f.puts self }
      end
    end
  end
end


Or may be Hash-syntax for append-mode should be written simply as two arguments:
obj.puts_to('file.txt', true)


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