Module: Yargi::Markable

Included in:
Digraph, Digraph::Edge, Digraph::Vertex
Defined in:
lib/yargi/markable.rb

Overview

Allows users to put its own marks on graph elements. A Hash-like API for setting and getting these marks is provided through [] and []=. When a Symbol object is used as a mark key (and provided it does’nt lead to a name collision), accessors are automatically defined as singleton methods (without creating an instance variable however).

Instance Method Summary collapse

Instance Method Details

#add_marks(marks = nil) ⇒ Object Also known as: merge_marks

Add all marks provided by a Hash instance marks.



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# File 'lib/yargi/markable.rb', line 46

def add_marks(marks=nil)
  marks.each_pair {|k,v| self[k]=v} if marks
  if block_given?
    result = yield self
    add_marks(result) if Hash===result
  end
end

#get_mark(key) ⇒ Object Also known as: []

Returns the mark value installed under key. Returns nil if no such mark.



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# File 'lib/yargi/markable.rb', line 23

def get_mark(key)
  @marks ? @marks[key] : nil;
end

#has_mark?(key) ⇒ Boolean

Checks if a given mark exists

Returns:

  • (Boolean) 


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# File 'lib/yargi/markable.rb', line 18

def has_mark?(key)
  @marks and @marks.has_key?(key)
end

#set_mark(key, value) ⇒ Object Also known as: []=

Sets a key/value pair as a mark. Overrides previous mark value if key is already in used. Automatically creates accessors if key is a Symbol and such methods do not already exists.



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# File 'lib/yargi/markable.rb', line 31

def set_mark(key, value)
  @marks = {} unless @marks
  @marks[key] = value
  if Symbol===key and not(self.respond_to?(key) or self.respond_to?("#{key}=".to_sym))
    instance_eval %Q{
      class << self
        def #{key}() @marks[:#{key}]; end
        def #{key}=(value) @marks[:#{key}]=value; end
      end
    }
  end
end

#tag(*modules) ⇒ Object

Tag this element with some modules



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# File 'lib/yargi/markable.rb', line 13

def tag(*modules)
  modules.each {|mod| self.extend(mod)}
end

#to_h(nonil = true) ⇒ Object

Converts this Markable to a Hash. When nonil is true, nil mark values do not lead to hash entries.



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# File 'lib/yargi/markable.rb', line 57

def to_h(nonil=true)
  return {} unless @marks
  marks = @marks.dup
  if nonil
    marks.delete_if {|k,v| v.nil?}
  end
  marks
end