Class: Fabulator::Grammar::Expr::RuleAlternative

Inherits:
Object
  • Object
show all
Defined in:
lib/fabulator/grammar/expr/rule_alternative.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ RuleAlternative

Returns a new instance of RuleAlternative.



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# File 'lib/fabulator/grammar/expr/rule_alternative.rb', line 5

def initialize
  @sequences = [ ]
end

Instance Method Details

#add_sequence(s) ⇒ Object 



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# File 'lib/fabulator/grammar/expr/rule_alternative.rb', line 9

def add_sequence(s)
  s = [ s ] unless s.is_a?(Array)
  @sequences += s
end

#parse(source) ⇒ Object 



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# File 'lib/fabulator/grammar/expr/rule_alternative.rb', line 14

def parse(source)
  results = [ ]
  @sequences.each do |sequence|
    res = source.attempt{ |s| sequence.parse(s) }
    raise Fabulator::Grammar::RejectParse if res.nil?
    res.children.each do |c|
      if c.name.nil?
        c.name = sequence.name if c.name.nil? && !sequence.name.nil?
        res.prune(c)
        results << c if !c.children.empty? || !c.value.nil?
      end
    end
    res.name = sequence.name unless sequence.name.nil?
    results << res if !res.children.empty? || !res.value.nil?
  end
  # now we want to merge all of the results
  if results.size > 1
    results = results.select{ |r| !r.name.nil? }
  end
  if !results.empty?
    source.set_result(results)
  end
end