module Yzz
Module Yzz
is a mixin that provides qualities of a ZZ structure cell to its includers.
A ZZ structure consists of ZZ objects, which exist in multiple dimensions. ZZ objects may be connected by directed edges – connections. Connected objects are called neighbors. Each connection belongs to exactly one 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 negward side of the neighbor. In each dimension, a ZZ object can have at most one posward and one negward neighbor. The relation is bijective: If B is the posward neighbor of A along dimension X, then A is a negward neighbor of B along X, and vice-versa. There is no limitation as to what objects can be connected. Circles are allowed. A ZZ object can even be connected to itself, forming a loop.
To this basic definition, Ted Nelson adds a bunch of additional terminology. A rank is a series of ZZ objects connected along the same dimension. A rank viewed horizontally is referred to as row. A rank viewed vertically is referred to as column. Ted Nelson's terms related not to the ZZ structure itself, but rather to the proposed user interface (such as cursor, view…) are not implemented in yzz, but rather in y_nelson gem.
Constants
- Dimensions
A hash whose [] method expects a dimension as an argument and returns a dimension-specific mixin.
- VERSION
Public Class Methods
An accessor method for a dimension-specific mixin from Yzz::Dimensions
hash.
# File lib/yzz.rb, line 48 def self.Dimension dimension Dimensions[ dimension ] end
Public Instance Methods
A reader method that returns a parametrized subclass of Yzz::SidePair
. This reader subsequently redefines itself (shadows itself with a newly defined singleton method) so as to always simply return the same parametrized subclass.
# File lib/yzz.rb, line 73 def SidePair SidePair.parametrize( zz: self ) .tap { |ç| define_singleton_method :SidePair do ç end } # TODO: How about # # SidePair.parametrize zz: self do # def SidePair; self end # end end
Returns a SidePair
instance along the requested dimension.
# File lib/yzz.rb, line 85 def along dimension zz_dimensions[ dimension ] end
Returns all sides actually connected to a zz object.
# File lib/yzz.rb, line 91 def connections zz_dimensions.map { |_, pair| [ pair.negward, pair.posward ] } .reduce( [], :+ ).select { |side| side.neighbor.is_a_zz? } end
Inspect string of the object.
# File lib/yzz.rb, line 124 def inspect to_s end
Returns all neighbors of a zz object.
# File lib/yzz.rb, line 98 def neighbors connections.map &:neighbor end
A string describing the object with respect to its zz qualities.
# File lib/yzz.rb, line 118 def to_s "#<Yzz, #{connections.size} conn.>" end
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.
# File lib/yzz.rb, line 106 def towards other connections.select { |side| side.neighbor == other } end
Prints the labels of the sides facing towards a given zz object.
# File lib/yzz.rb, line 112 def tw other puts towards( other ).map &:label end
A reader method that returns a hash whose [] method returns an appropriate side pair for a supplied dimension. The hash is constructed upon first call of the reader. This reader subsequently redefines itself (shadows itself with a newly defined singleton method) so as to always simply return the same hash.
# File lib/yzz.rb, line 57 def zz_dimensions Hash.new { |ꜧ, missing_dimension| ꜧ[ missing_dimension ] = Class.new SidePair() do include ::Yzz.Dimension missing_dimension # ::Yzz just in case end.new }.tap { |ꜧ| define_singleton_method :zz_dimensions do ꜧ end } # TODO: This second subclassing of SidePair() in effect acts as a # singleton class. How about making it a true singleton class and # just extending the objects with the mixin? end