Class: WorldState

Inherits:
String
  • Object
show all
Defined in:
lib/world_state.rb

Overview

class WorldState

Defined Under Namespace

Classes: InvalidDimension, InvalidPosition, InvalidState

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(width:, height:, init: nil) ⇒ WorldState

Returns a new instance of WorldState

Parameters:

  • width (Integer)
  • height (Integer)
  • init (String)

Raises:



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# File 'lib/world_state.rb', line 20

def initialize(width:, height:, init: nil)
  raise InvalidDimension if width < 1 || height < 1
  raise InvalidState if init && width * height != init.length

  init ? super(init) : super(' ' * (width * height))
  @width = width
  @height = height
end

Instance Attribute Details

#height ⇒ Integer (readonly)

Returns the heigh of the world

Returns:

  • (Integer) —

    the heigh of the world



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# File 'lib/world_state.rb', line 8

def height
  @height
end

#width ⇒ Integer (readonly)

Returns the width of the world

Returns:

  • (Integer) —

    the width of the world



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# File 'lib/world_state.rb', line 6

def width
  @width
end

Instance Method Details

#dead?(pos) ⇒ Boolean

true if the cell at position is dead and false if it is live

Parameters:

  • pos (Integer)

Returns:

  • (Boolean) 


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# File 'lib/world_state.rb', line 40

def dead?(pos)
  valid_position?(pos)
  self[pos] && self[pos] == ' '
end

#e(pos) ⇒ Integer Also known as: east

The position east (right) of the position

Parameters:

  • pos (Integer)

Returns:

  • (Integer) 


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# File 'lib/world_state.rb', line 96

def e(pos)
  valid_position?(pos)
  return pos + 1 - @width if (pos % @width) == @width - 1 # right edge case
  pos + 1
end

#live?(pos) ⇒ Boolean

true if the cell at position is live and false if it is dead

Parameters:

  • pos (Integer)

Returns:

  • (Boolean) 


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# File 'lib/world_state.rb', line 32

def live?(pos)
  valid_position?(pos)
  self[pos] && self[pos] != ' '
end

#n(pos) ⇒ Integer Also known as: north

the position north (up) of the position

Parameters:

  • pos (Integer)

Returns:

  • (Integer) 


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# File 'lib/world_state.rb', line 67

def n(pos)
  valid_position?(pos)
  return pos + @width * (@height - 1) if (pos / @width).zero? # top edge case
  pos - @width
end

#ne(pos) ⇒ Integer Also known as: northeast

The position northest (up, right) of the position

Parameters:

  • pos (Integer)

Returns:

  • (Integer) 


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# File 'lib/world_state.rb', line 77

def ne(pos)
  valid_position?(pos)
  e(n(pos))
end

#neighborhood(pos) ⇒ Array<String>

The player chars or emptiness around the position (includes position)

Parameters:

  • pos (Integer) —

    a position in the world

Returns:

  • (Array<String>) 


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# File 'lib/world_state.rb', line 139

def neighborhood(pos)
  valid_position?(pos)

  [
    self[nw(pos)], self[n(pos)], self[ne(pos)],
     self[w(pos)],  self[pos],   self[e(pos)],
    self[sw(pos)], self[s(pos)], self[se(pos)]
  ]
end

#next(pos) ⇒ String

The player char of this position in the next state; space if dead

Parameters:

  • pos (Integer)

Returns:

  • (String) 


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# File 'lib/world_state.rb', line 153

def next(pos)
  valid_position?(pos)
  nhood = neighborhood(pos)

  return handle_dead(nhood) if p(pos) == ' '

  # overpopulation
  return ' ' if nhood.count(' ') < 5
  # underpopulation
  return ' ' if nhood.count(' ') > 6

  return handle_two_neighbors(nhood) if nhood.count(' ') == 6

  handle_three_neighbors(nhood)
end

#nw(pos) ⇒ Integer Also known as: northwest

the position northwest (up, left) of the position

Parameters:

  • pos (Integer)

Returns:

  • (Integer) 


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# File 'lib/world_state.rb', line 58

def nw(pos)
  valid_position?(pos)
  w(n(pos))
end

#p(pos) ⇒ String Also known as: player

the player character for a live cell, or space if dead cell

Parameters:

  • pos (Integer)

Returns:

  • (String) 


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# File 'lib/world_state.rb', line 48

def p(pos)
  valid_position?(pos)
  return if self[pos] == ' '
  self[pos]
end

#s(pos) ⇒ Integer Also known as: south

The position south (down) of the position

Parameters:

  • pos (Integer)

Returns:

  • (Integer) 


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# File 'lib/world_state.rb', line 115

def s(pos)
  valid_position?(pos)
  return pos % @width if (pos / @width) == @height - 1 # bottom edge case
  pos + @width
end

#se(pos) ⇒ Integer Also known as: southeast

The position southeast (down, left) of the position

Parameters:

  • pos (Integer)

Returns:

  • (Integer) 


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# File 'lib/world_state.rb', line 125

def se(pos)
  valid_position?(pos)
  e(s(pos))
end

#sw(pos) ⇒ Integer Also known as: southwest

The position southeast (down, left) of the position

Parameters:

  • pos (Integer)

Returns:

  • (Integer) 


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# File 'lib/world_state.rb', line 106

def sw(pos)
  valid_position?(pos)
  w(s(pos))
end

#w(pos) ⇒ Integer Also known as: west

The position west (left) of the position

Parameters:

  • pos (Integer)

Returns:

  • (Integer) 


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# File 'lib/world_state.rb', line 86

def w(pos)
  valid_position?(pos)
  return pos - 1 + @width if (pos % @width).zero? # left edge case
  pos - 1
end