Ruby Pipes

gistfile1.rb

#/usr/bin/env ruby
# encoding: utf-8

APP_ROOT=File.expand_path('../../', __FILE__)

class Chain
  
  def initialize(*procs) 
    @chain = procs
  end

  def |(proc)
    @chain << proc
    self
  end

  def call(args)
    @chain.inject(args) {|x, p| p.call(x) }
  end
  alias [] call

end

class Proc
  def |(proc)
    Chain.new(self, proc)
  end
end

# f = lambda {|x| x * 7} | lambda {|x| x + 10 } | lambda {|x| -x }
# puts f.call(5)
# 
# puts f[0]

# class Method
#   def |(meth)
#     Chain.new(self, meth.to_proc)
#   end  
# end

class BaseStep 

  def |(proc)
    Chain.new(self, proc)
  end
  
end

class ReadArticles < BaseStep
  def call(args)
    puts "Reading articles from #{args}"
    return "loaded #{args}"
  end
end

extract_body = lambda do |args|
  puts "extracting body"
  return "extracted body"
end

def write_html(html)
  puts "writing html"
  return "done"
end

class Symbol
  # TOTAL HACK
  def call(args)
    Object.send(self, args)
  end
end

transform = ReadArticles.new | extract_body | :write_html
puts transform.call("#{APP_ROOT}/examples/articles")