Class: LineFolder

Inherits:
Object
  • Object
show all
Defined in:
lib/threesmodel/line_folder.rb

Overview

The LineFolder can fold an array with four cells according to the rules of threes.

Instance Method Summary collapse

Constructor Details

#initialize ⇒ LineFolder

Returns a new instance of LineFolder.



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# File 'lib/threesmodel/line_folder.rb', line 5

def initialize
  Array.class_eval do
    # Determines the "wall" position and the collapses the first to collapsible cells inserting a zero at the end. Assumes a foldable line.
    def squash
      array = Array.new(self)
      wall_index = wall_index_of
      array[wall_index] = array[wall_index] + array[wall_index + 1]
      while wall_index < 2
        array[wall_index + 1] = array[wall_index + 2]
        wall_index += 1
      end
      array[3] = 0
      return array
    end

    def wall_index_of
      return 3 if self == ([1,1,1,1] or [2,2,2,2])
      return 3 if self[1..3] == [0,0,0]
      return 0 if self[0] == 0
      return 0 if self[0] == 1 and self[1] == 2
      return 0 if self[0] == 2 and self[1] == 1
      if self[0] > 2
        return 0 if self[0] == self[1]
      end
      return 3 if self[2..3] == [0,0]
      return 1 if self[1] == 0
      return 1 if (self[0] != self[1]) and self[1] == 1 and self[2] == 2
      return 1 if (self[0] != self[1]) and self[1] == 2 and self[2] == 1
      return 1 if (self[0] == self[1]) and self[1] == 1 and self[2] == 2
      return 1 if (self[0] == self[1]) and self[1] == 2 and self[2] == 1
      if self[1] > 2
        return 1 if self[1] == self[2]
      end
      return 2 if self[2] == 0
      return 2 if self[2] == 1 and self[3] == 2
      return 2 if self[2] == 2 and self[3] == 1
      if self[2] > 2
        return 2 if self[2] == self[3]
      end
      3
    end

  end
end

Instance Method Details

#can_fold?(line) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/threesmodel/line_folder.rb', line 58

def can_fold?(line)
  return line.wall_index_of < 3
end

#fold(line) ⇒ Object 



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# File 'lib/threesmodel/line_folder.rb', line 50

def fold(line)
  if can_fold?(line) then
    return line.squash
  else
    return line
  end
end