#!/usr/bin/env ruby -Ku

# encoding: utf-8

require 'veritas'
require 'csv'

rows = Enumerator.new do |yielder|
  CSV.foreach(DATA) do |row|
    yielder << [ row[0].to_i, row[1] ]
  end
end

relation = Veritas::Relation.new([ [ :id, Integer ], [ :char, String ] ], rows)
relation = relation.restrict { |r| r.id.gte(2) }
relation = relation.project([ :id ])
relation = relation.rename(:id => :csv_id)
relation = relation.sort_by { |r| r.csv_id }
relation = relation.take(2)
relation = relation.drop(1)

relation.each do |tuple|
  puts tuple.inspect
end

__END__
1,a
2,b
3,c
4,d
5,e