Class: Spoom::Poset

Inherits:
Object
  • Object
show all
Defined in:
lib/spoom/poset.rb

Overview

A Poset is a set of elements with a partial order relation.

The partial order relation is a binary relation that is reflexive, antisymmetric, and transitive. It can be used to represent a hierarchy of classes or modules, the dependencies between gems, etc. : [E < Object]

Defined Under Namespace

Classes: Element, Error

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Poset

: -> void



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# File 'lib/spoom/poset.rb', line 14

def initialize
  @elements = {} #: Hash[E, Element[E]]
end

Instance Method Details

#[](value) ⇒ Object

Get the POSet element for a given value

Raises if the element is not found : (E value) -> Element

Raises:



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# File 'lib/spoom/poset.rb', line 22

def [](value)
  element = @elements[value]
  raise Error, "POSet::Element not found for #{value}" unless element

  element
end

#add_direct_edge(from, to) ⇒ Object

Add a direct edge from one element to another

Transitive edges (transitive closure) are automatically computed. Adds the elements if they don’t exist. If the direct edge already exists, nothing is done. : (E from, E to) -> void



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# File 'lib/spoom/poset.rb', line 50

def add_direct_edge(from, to)
  from_element = add_element(from)
  to_element = add_element(to)

  # We already added this direct edge, which means we already computed the transitive closure
  return if from_element.parents.include?(to)

  # Add the direct edges
  from_element.dtos << to_element
  to_element.dfroms << from_element

  # Compute the transitive closure

  from_element.tos << to_element
  from_element.froms.each do |child_element|
    child_element.tos << to_element
    to_element.froms << child_element

    to_element.tos.each do |parent_element|
      parent_element.froms << child_element
      child_element.tos << parent_element
    end
  end

  to_element.froms << from_element
  to_element.tos.each do |parent_element|
    parent_element.froms << from_element
    from_element.tos << parent_element

    from_element.froms.each do |child_element|
      child_element.tos << parent_element
      parent_element.froms << child_element
    end
  end
end

#add_element(value) ⇒ Object

Add an element to the POSet : (E value) -> Element



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# File 'lib/spoom/poset.rb', line 31

def add_element(value)
  element = @elements[value]
  return element if element

  @elements[value] = Element.new(value) #: Element[E]
end

#direct_edge?(from, to) ⇒ Boolean

Is there a direct edge from ‘from` to `to`? : (E from, E to) -> bool

Returns:

  • (Boolean) 


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# File 'lib/spoom/poset.rb', line 97

def direct_edge?(from, to)
  self[from].parents.include?(to)
end

#edge?(from, to) ⇒ Boolean

Is there an edge (direct or indirect) from ‘from` to `to`? : (E from, E to) -> bool

Returns:

  • (Boolean) 


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# File 'lib/spoom/poset.rb', line 88

def edge?(from, to)
  from_element = @elements[from]
  return false unless from_element

  from_element.ancestors.include?(to)
end

#element?(value) ⇒ Boolean

Is the given value a element in the POSet? : (E value) -> bool

Returns:

  • (Boolean) 


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# File 'lib/spoom/poset.rb', line 40

def element?(value)
  @elements.key?(value)
end

#show_dot(direct: true, transitive: true) ⇒ Object

Show the POSet as a DOT graph using xdot (used for debugging) : (?direct: bool, ?transitive: bool) -> void



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# File 'lib/spoom/poset.rb', line 103

def show_dot(direct: true, transitive: true)
  Open3.popen3("xdot -") do |stdin, _stdout, _stderr, _thread|
    stdin.write(to_dot(direct: direct, transitive: transitive))
    stdin.close
  end
end

#to_dot(direct: true, transitive: true) ⇒ Object

Return the POSet as a DOT graph : (?direct: bool, ?transitive: bool) -> String



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# File 'lib/spoom/poset.rb', line 112

def to_dot(direct: true, transitive: true)
  dot = +"digraph {\n"
  dot << "  rankdir=BT;\n"
  @elements.each do |value, element|
    dot << "  \"#{value}\";\n"
    if direct
      element.parents.each do |to|
        dot << "  \"#{value}\" -> \"#{to}\";\n"
      end
    end
    if transitive # rubocop:disable Style/Next
      element.ancestors.each do |ancestor|
        dot << "  \"#{value}\" -> \"#{ancestor}\" [style=dotted];\n"
      end
    end
  end
  dot << "}\n"
end