Class: ABNF::Var

Inherits:
Elt
  • Object
show all
Defined in:
lib/abnf/abnf.rb,
lib/abnf/regexp.rb,
lib/abnf/grammar.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from Elt

#*, #+, #empty_sequence?, #empty_set?, #remove_left_recursion, #remove_right_recursion, #rep, #|

Constructor Details

#initialize(name) ⇒ Var

Returns a new instance of Var.



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# File 'lib/abnf/grammar.rb', line 149

def initialize(name)
  @name = name
end

Instance Attribute Details

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/abnf/grammar.rb', line 152

def name
  @name
end

Instance Method Details

#each_var {|@name| ... } ⇒ Object

Yields:



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# File 'lib/abnf/grammar.rb', line 154

def each_var(&block) yield @name end

#recursion(syms, lhs) ⇒ Object 



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# File 'lib/abnf/regexp.rb', line 354

def recursion(syms, lhs)
  if lhs == self.name
	JustRecursion | SelfRecursion
  elsif syms.include? self.name
	JustRecursion
  else
    NonRecursion
  end
end

#remove_just_recursion(n) ⇒ Object 



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# File 'lib/abnf/regexp.rb', line 364

def remove_just_recursion(n)
  if n == self.name
    EmptySet
  else
	self
  end
end

#split_left_recursion(n) ⇒ Object Also known as: split_right_recursion 



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# File 'lib/abnf/regexp.rb', line 372

def split_left_recursion(n)
  if n == self.name
	[EmptySet, EmptySequence]
  else
	[self, EmptySet]
  end
end

#split_recursion(n) ⇒ Object 



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# File 'lib/abnf/regexp.rb', line 381

def split_recursion(n)
  if n == self.name
	[EmptySet, EmptySet, EmptySet]
  else
	[EmptySet, self, EmptySet]
  end
end

#subst_var(&block) ⇒ Object 



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# File 'lib/abnf/grammar.rb', line 155

def subst_var(&block) yield(@name) || self end

#useful?(useful_names) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/abnf/abnf.rb', line 123

def useful?(useful_names) useful_names[@name] end