seq

#!/usr/bin/env ruby
# Author: Joseph Pecoraro
# Date: Wednesday, September 23, 2009
# Description: A "seq" like program for the mac!

class Seq
  attr_reader :start, :step, :end
  
  def initialize(args)
    @start, @step, @end = 1, 1, 0
    case args.size
    when 1 then
      @end = args[0].to_i.abs
    when 2 then 
      @start = args[0].to_i.abs
      @end = args[1].to_i.abs
    when 3 then
      @start = args[0].to_i.abs
      @step = args[1].to_i.abs
      @end = args[2].to_i.abs
    end
    
    validate!
  end
  
  def validate!
    @start = @end if @end < @start
    @step = @step.abs if @step < 0
  end
  
  def print
    puts self.to_a
  end
  
  def to_a
    arr = []
    curr = @start
    while (curr <= @end)
      arr.push(curr)
      curr += @step
    end
    arr
  end

end

# When run as as script
if $0 == __FILE__
	
	# Handle ^C Interrupt
	trap("INT") { puts; exit }
	
	# Usage
  if ARGV.size.zero?
    program_name = $0.split(/\//).last
    puts "usage: #{program_name} END"
    puts "usage: #{program_name} START END"
    puts "usage: #{program_name} START STEP END"
  else
    Seq.new(ARGV).print
  end

end