Partial Apertium's stream parser (for parsing biltrans result)

apertium.rb

module Apertium
  OUTSIDE_WORD = 0
  INSIDE_WORD = 1
  
  class B
    attr_reader :text
    def initialize(text)
      @text = text
    end
    
    def parse
      self
    end
  end
  
  class Analyse
    attr_reader :lemma, :tags
    def initialize(lemma, tags)
      @lemma = lemma
      @tags = tags
    end
  end
  
  class AmbiLu
    attr_reader :analyses
    def initialize(analyses)
      @analyses = analyses
    end
  end
  
  class W0
    attr_reader :text
    def initialize(text)
      @text = text
    end
    
    def parse_analisis(t)
      t = t.split(/(<[^>]+>)/).select{|w| w != ""}    
      lemma = t[0]
      tags = t[1..-1].map{|tag| tag[1..-2]}
      return Analyse.new(lemma, tags)
    end
    
    def parse
      s = 0
      analyses = []
      text = @text[1..-2]
      for i in 0..(text.length-1)
        if text[i] == '/' and (i == 0 or text[i] != '\\')
          analyses << parse_analisis(text[s..(i-1)])
          s = i+1
        end
      end
      if s < text.length
        analyses << parse_analisis(text[s..(text.length-1)])
      end
      return AmbiLu.new(analyses)
    end
  end

  class StreamParser
    
    def initialize
    end
    
    def parse(stream)    
      pass0 = parse0(stream)
      return pass0.map{|t| t.parse}    
    end
    
    def parse0(stream)
      state = OUTSIDE_WORD
      s = 0
      
      pass0 = []
      
      for i in 0 .. (stream.length - 1)
        case state
        when OUTSIDE_WORD
          if stream[i] == '^' and (i == 0 or stream[i] != '\\')
            if i > 0
              if i-1 >= s
                pass0 << B.new(stream[s..(i-1)])
              end
            end
            s = i
            state = INSIDE_WORD
          end
        when INSIDE_WORD
          if stream[i] == '$' and (i == 0 or stream[i] != '\\')
            state = OUTSIDE_WORD
            pass0 << W0.new(stream[s..(i-1)])
            s = i + 1
          end
          
        end
      end #for
      
      return pass0
    end
  end
end