Class: Yagg::Generator

Inherits:
Object
  • Object
show all
Defined in:
lib/yagg/gen.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(input) ⇒ Generator

Returns a new instance of Generator.



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# File 'lib/yagg/gen.rb', line 7

def initialize(input)
  @input = input
  @indent = 0
  self.result = ""
end

Instance Attribute Details

#resultObject

Returns the value of attribute result.



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# File 'lib/yagg/gen.rb', line 6

def result
  @result
end

Instance Method Details

#`(text) ⇒ Object



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# File 'lib/yagg/gen.rb', line 35

def `(text)
  @result << make_indent(@indent, text)
end

#generate(under = "GG") ⇒ Object



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# File 'lib/yagg/gen.rb', line 185

def generate(under = "GG")
  `module #{under}\n  Scope = self\n`      
  indent 2
    generate_header
    generate_lexels
    generate_rules
  indent -2
  `end\n`
end

#generate_headerObject



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# File 'lib/yagg/gen.rb', line 47

def generate_header
  <<~`EOF`
    class Lexel
      attr_accessor :value
      def values
        [value]
      end
      def typeid
        -1
      end
      def initialize(value)
        raise TypeError unless self.class.check(value)
        if self.class === value
           self.value = value.value
        elsif Lexel === value || Rule === value
           raise TypeError   
        else
           self.value = value
        end
      end 
      def self.check(value)
        if Lexel === value || Rule === value
           return self === value
        end
        true
      end
      def to_text
        value.to_s
      end
    end

    Unchecked = Struct.new(:values, :typeid)
        
    class Rule
      attr_accessor :typeid, :values
      def to_text
        values.map{|x| x.to_text}.join
      end
      def initialize(*values)
        if values.length == 1 && Unchecked === values[0]
          self.values   = values[0].values
          self.typeid = values[0].typeid
        else
          old = values
          typeid, values = self.class.check(values)
          raise TypeError, "\#{self.class.to_s}:can't find rule for \#{old}" unless typeid
          if typeid == -1
             self.values = values[0].values
             self.typeid = values[0].typeid
          else
             self.values   = values
             self.typeid = typeid
          end
        end
      end 

      def self.grammel(a)
         case a
         when /^[A-Z]/ then Scope.const_get(a.upcase)
         when /^[a-z]/ then Scope.const_get(a.capitalize.gsub(/_([a-z])/){ $1.upcase })
         when /^'(.)'/ then $1
         else
           raise TypeError, "unknown grammar token \#{a}"
         end
      end

      def self.check_single(pattern, values)
  i = 0
         j = 0
         output = []
         while i < values.length && j < pattern.length
           u = grammel(pattern[j])
           if Class === u
             output << u.new(values[i])
           else
             return nil if u != values[i]
             output << values[i]
           end
           i += 1
           j += 1               
         end
         output
      rescue TypeError
      end

      def to_text
        self.values.map{|x| x.to_text}.join       
      end

      def self.check_one(value, memo = {})
  self::Includes.each{|x|
           next if memo[x]
           u = grammel(x)
           case u
    when String
              return value if u == value
           when lambda{|x| x < Lexel}
                return u.new(value) if u.check(value)
           else
              if u === value
                return u.new(Unchecked.new([value], -1))
else
                r = u.check_one(value, memo.update({u: 1}))
                return self.new(Unchecked.new([r], -1)) if r
              end
           end
         }
         nil
      end

      def self.check(values)
        if values.length == 1 
          if self === values[0]
            return -1, values
          elsif (r = check_one(values[0], {}))
            if self === r
              return -1, r.values
            else
              return -1, [r]
            end
          else 
            return nil
          end
          return nil
        end
        
        self::Rules.each_with_index{|k, i|
           next if k.size != values.size
           r = check_single(k, values)
    return i, r if r
        }
           
        nil
      end
    end
  EOF
end

#generate_lexelsObject



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# File 'lib/yagg/gen.rb', line 13

def generate_lexels
  @input.tokens.each{|x|
    `#{x.upcase} = Class.new(Lexel)\n`
  }
end

#generate_rulesObject



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# File 'lib/yagg/gen.rb', line 26

def generate_rules
  @input.rules.each{|k, v|
    `class #{rule_name_case(k)} < Rule\n`
    `  Rules      = #{v.select{|x| x.size != 1}.inspect}\n`
    `  Includes   = #{v.select{|x| x.size == 1}.flatten}\n`
    `end\n`
  }
end

#indent(a = 0) ⇒ Object



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# File 'lib/yagg/gen.rb', line 43

def indent(a = 0)
  @indent += a
end

#make_indent(num, text) ⇒ Object



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# File 'lib/yagg/gen.rb', line 39

def make_indent(num, text)
  text.split(/(\n)/).map{|x| " "*num << x}.join
end