From: Ma Sz Date: 2011-03-11T07:49:33+09:00 Subject: problem with compilation I'm totally newbie at Ruby. What is wrong whit this code class Hexagrid @@grid = [%w{ 0 1 2 3 }, %w{ 4 5 6 7 }, %w{ 8 9 A B }, %w{ C D E F }] def initialize @stacks = Hash.new end def parse( string ) while string =~ /^\s*(\S+)\s*\{([^\}]+)\}\s*;?\s*(.*)/ output = '' stack = @stacks[$1] ||= Hash.new data = stack[:data] ||= Array.new pointer = stack[:pointer] ||= [0,0] $2.split(//).each do |c| if c == '>' then pointer[1] += 1 elsif c == '<' then pointer[1] -= 1 elsif c == 'v' then pointer[0] += 1 elsif c == '^' then pointer[0] -= 1 elsif c == '!' then pointer = [0,0]; data.clear elsif c == '+' then data.unshift @@grid[pointer[0]][pointer[1]] elsif c == 'o' then output << data.join end end string = $3 end return output.reverse end def english( string ) return parse(string).scan(/.{2}/).collect{ |tuple| tuple.hex.chr }.join end end hex = Hexagrid.new while not $stdin.eof? puts hex.english(gets) end I've got D:\NetBeansProjects\InterpreterHexagrid\lib\main.rb:33:in `parse': undefined method `reverse' for nil:NilClass (NoMethodError) from D:\NetBeansProjects\InterpreterHexagrid\lib\main.rb:37:in `english' from D:\NetBeansProjects\InterpreterHexagrid\lib\main.rb:43 -- Posted via http://www.ruby-forum.com/.