Better Formatting for DLV / DLV Complex Answer Sets

dlv_formatter.rb

#!/usr/bin/env ruby

output = %x(/usr/local/bin/dlv-complex -silent #{ARGV[0]})

output = output.scan(/[[:print:]]/).join

@answerset = Hash.new

def reset
  @bracket_level = 0
  @current_pred = ""
  @current_arg = ""
end

def addLiteral
  return unless @current_pred && @current_pred.any?

  @answerset[@current_pred] ||= Array.new
  @answerset[@current_pred] << @current_arg
  reset
end

def printCurrent(number)
  puts "ANSWERSET #{number}:"

  @answerset.sort {|a,b| a[0] <=> b[0]}.each do |pred, arg|
    if arg.size < 2
      puts "   #{pred}#{arg}"
    elsif arg.size < 6
      puts "   " + arg.map {|a| "#{pred}#{a}"}.join(", ")
    else
      puts "   " + arg[0..3].map {|a| "#{pred}#{a}"}.join(", ") + ", ..., #{pred}#{arg[-1]}"
    end
  end

  puts ""

  @answerset = Hash.new
end

curlyLevel = 0; i = 0

output.each_char do |c|

  # Several answersets
  if c == '{' && curlyLevel == 0
    reset
    curlyLevel = 1
  elsif c == '}' && curlyLevel == 1
    curlyLevel = 0
    addLiteral
    printCurrent(i+=1)
  else

    # Within answerset
    next if c == ' ' && @bracket_level == 0

    if c == ',' && @bracket_level == 0
      addLiteral
    else

      curlyLevel += 1 if c == '{'
      curlyLevel -= 1 if c == '}'

      @bracket_level += 1 if c == '('

      if @bracket_level == 0
        @current_pred += c
      else
        @current_arg += c
      end

      @bracket_level -= 1 if c == ')'
    end
  end
end

example.dlv

test(a).
test(b).

numbers(1..10).

test(c) :- test(a), test(b).
test(d) :- test(a), not test(b).

fact.

output.txt

ANSWERSET 1:
   fact
   numbers(1), numbers(2), numbers(3), numbers(4), ..., numbers(10)
   test(a), test(b), test(c)