Contents

module Yagg
  Error = Class.new(Exception)
  class Parser
    attr_accessor :header, :body, :tokens, :rules, :token_groups
    ParseError = Class.new(Exception)
    def initialize(text)
      @source = text
    end

    def result
      self
    end

    def setup_sections
      if @source =~ /([\w\W]*?)^%%\s*([\w\W]*?)^%%\s*/
        self.header, self.body, * = $1, $2
      else
        raise ParseError, "can't recognize format"
      end
    end

    def parse_tokens
      self.tokens = self.header.scan(/^%token(.*)/).flat_map{|x| x.flat_map{|y| y.split(" ")}}
    end

    def parse_rule(arr)
       arr = arr[0..-1]
       name = arr.shift
       arr.shift
       groups = [[]]
       arr.each do |t|
         if t == '|'
           groups.push []
         else
           groups.last.push t
         end
       end
       {name => groups}
    end

    def parse_rules
       tokens = self.body.scan(/[^'\s]+|'.'/).to_a
       self.token_groups = [[]]
       tokens.each do |t|
         if t != ';'
           self.token_groups.last << t
         else
           self.token_groups << []
         end
       end
       self.token_groups.pop if self.token_groups.last.empty?
       self.rules = self.token_groups.inject({}){|a, b| a.update(parse_rule(b))}
    end

    def parse
      setup_sections
      parse_tokens
      parse_rules
    end 
  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
yagg-0.1.1	lib/yagg/parsery.rb