Defining a Polyrex schema

Tuesday, 04 May 2010 14:03

To create a Polyrex document from a string representation of a schema (e.g. a[n,x1,x2]/b[y,y2]/c[n]), the following script can be used:



require 'rexml/document'



class PolyrexSchema

  include REXML



  def initialize(s)



    @doc = Document.new

    node = Element.new 'root'

    @doc.add node



    s.scan(/\w+\[[^\]]*\]|\w+/).each do |x|

      b1, b2 = x.split('[')

      if b2 then

        node = append_node node, b1 do |summary|

          b2.scan(/\w+(?=[,\]])/).each {|x| summary.add Element.new x}

        end

      else

        node = append_node node, x

      end

    end



  end



  def to_s

    @doc.to_s

  end



  private



  def append_node(node, name)

    new_node = Element.new name

    summary = Element.new 'summary'

    yield(summary) if block_given?

    new_node.add summary

    records = Element.new 'records'

    new_node.add records

    node.add new_node

    records

  end

end



puts Document.write PolyrexSchema.new('q[n,x1,x2]/b1[y,y2]/c[n]').to_s

# see listing 1.

puts Document.write PolyrexSchema.new('q[n,x1,x2],b1[y,y2],c,g').to_s

# see listing 2.

listing 1.

listing 2.