Module: Yzz

Defined in:
lib/yzz.rb,
lib/yzz/version.rb

Overview

Yzz implements Ted Nelson’s zz (hyperorthogonal, Zig-Zag…) structure. It provides a mixin that imbues objects with zz properties.

A zz structure consists of zz objects, which exist in multiple dimensions. Zz objects can be connected by directed edges – connections. Connected objects are called neighbors. Each connection belongs to some dimension. A zz object is considered as having two sides in each dimension: posward side and negward side. A connection always points away from the posward side, and towards the neighbor’s negward side. In each dimension, zz object can have at most one posward and one negward neighbor. A zz object can be connected to itself, forming a loop.

To these basic properties, Ted Nelson adds a bunch of other terminology. A rank is a series of zz objects connected along one dimension. A rank viewed horizontally is referred to as row. A rank viewed vertically is referred to as column.

Mixin defining Zz structure (aka. hyperorthogonal structure). As represented by YTed::Zz, a Zz structure is a collection of objects, whose connectivity is defined in a multidimensional space in such way, that each object, along each dimension, has at most one posward neighbor, and one negward neighbor. The relation is bijective: If B is a posward neighbor of A along some dimension, then A must be a negward neighbor of B along that dimension, and vice-versa.

Defined Under Namespace

Classes: Side, SidePair

Constant Summary collapse

VERSION = 
"2.0.2"

Instance Method Summary collapse

Instance Method Details

#along(dimension) ⇒ Object

Returns a SidePair instance along the requested dimension.



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# File 'lib/yzz.rb', line 44

def along dimension
  @zz_dimensions[ dimension ]
end

#connections ⇒ Object Also known as: connectivity

Returns all sides actually connected to a zz object.



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# File 'lib/yzz.rb', line 50

def connections
  @zz_dimensions.map { |_, pair| [ pair.negward, pair.posward ] }
    .reduce( [], :+ ).select { |side| side.neighbor.is_a_zz? }
end

#initialize(*args) ⇒ Object

Adds initialization of the @zz_dimensions hash to #initialize.



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# File 'lib/yzz.rb', line 34

def initialize *args
  @zz_dimensions = Hash.new { |

#neighbors ⇒ Object

Returns all neighbors of a zz object.



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

def neighbors
  connections.map &:neighbor
end

#towards(other) ⇒ Object

Returns all sides facing another zz object supplied as argument. (Note that this can be more than 1 side: object A can be connected to B along more than 1 dimension.



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# File 'lib/yzz.rb', line 66

def towards other
  connectivity.select { |side| side.neighbor == other }
end