def dbg(a, s=nil, &b)
    begin
        v = eval(a.to_s, b.binding)
    rescue Exception => e
        v = e.to_s.split("\n").first
    end
    s = " ------ " if s == 1
    v = "nil" if v.to_s == ""
    puts "#{s}#{a} : #{v}#{s}" if not @dbg == 0
end
#dbg(:var) {}
#@dbg = 0