gistfile1.rb

class Object
  def backtrace
    Backtrace.new
  end
end

class Backtrace
  class Line
    attr_reader :file, :line, :name
    def initialize(line)
      /^(?<file>[^:]+):(?<line>\d+):in `(block.+?)?(?<name>[^ ']+)'/u =~ line
      @file = file.match(/^\((?<ctx>.+)\)$/) ? $~[:ctx] : File.expand_path(file)
      @line, @name = line.to_i, name.to_sym
    end
    
    def to_s
     "#{file}:#{line} in `#{name}'"
    end
   alias :inspect :to_s 
  end

  attr_reader :lines
  
  include Enumerable

  def initialize
    @lines = caller.map   { |line| Line.new(line) }
                   .reject{ |line| line.file == File.expand_path(__FILE__) }
  end

  def name(idx=0)
    lines[idx].name
  end

  def file(idx=0)
    lines[idx].file
  end

  def line(idx=0)
    lines[idx].line
  end

  def [](idx)
    lines[idx]
  end
  
  def each
    lines.each { |line| yield line }
  end
end