StreamPrinter

stream_printer.rb

# Stream of consciousness development. Copy/Paste into pry or irb.

require 'stringio'

def stream_print(stream, object)
  stream << object.to_str if object.respond_to?(:to_str)
  stream
end

io = StringIO.new
ar = %w(foo bar baz qux 1 2 3)
ar.reduce(io) { |str, obj| stream_print(str, obj); str << "\n" }
puts io.string

io = StringIO.new
ar[2] = nil
ar.reduce(io) { |str, obj| stream_print(str, obj); str << "\n" }
puts io.string

def stream_print(stream, object)
  case
  when object.nil?
    stream.puts
  when object.respond_to?(:to_str)
    stream.puts(object.to_str)
  else
    nil
  end
  stream
end

io = $stdout
ar.reduce(io) { |str, obj| stream_print(str, obj) }

# MOAR POWOR!

require 'forwardable'

class StreamPrinter
  extend Forwardable
  def_delegators :@content, :respond_to?, :to_str, :to_s

  attr_reader :content

  def initialize(content)
    @content = content
  end

  def printable?
    respond_to?(:to_str)
  end

  def print(stream)
    stream.puts(to_str) if printable?
    stream
  end

  def method_missing(*args, &block)
    StreamPrinter.new(content.public_send(*args, &block))
  rescue NoMethodError
    StreamPrinter.new(nil)
  end
end

ar.map { |obj| StreamPrinter.new(obj) }.
  reduce(io) { |str, obj| obj.print(str) }


Contact = Struct.new(:name, :address, :phone, :email) do
  def to_str
    "#{name}\n#{address}\n#{phone}\n,#{email}"
  end
end

Name = Struct.new(:first_name, :last_name) do
  def to_str
    "#{first_name} #{last_name}"
  end
end

Address = Struct.new(:street_address, :city, :state, :zip) do
  def to_str
    "#{street_address}\n#{city}, #{state} #{zip}"
  end
end

StreetAddress = Struct.new(:number, :street_name, :sub_address) do
  def to_str
    "#{number} #{street_name}" + (" #{sub_address}" || "")
  end
end

def print_mailbox_label(stream, contact)
  printer = StreamPrinter.new(contact)
  return stream unless ( printer.name.last_name.printable? &&
                         printer.address.street_address.sub_address.printable? )

  printer.name.last_name.print(stream)
  printer.address.street_address.sub_address.print(stream)
  stream
end

io = StringIO.new

contact = Contact.new(
  Name.new("Bibble", "Bobble"), 
  Address.new(
    StreetAddress.new("45", "W Hamshire Ln", "5")))

print_mailbox_label(io, contact)

# The cycle continues ...