multi_select.rb

require 'ruby-debug'

def multi_split(str, tokens)
  results = []
  buffer = ""
  maybe_token = false
  temp_str = ""
  str.each_char do |c|
    if maybe_token
      if is_token?(temp_str + c, tokens)
        maybe_token, temp_str = reset_state(maybe_token, temp_str)
        results << buffer
        buffer = ""
      elsif is_token_prefix?(temp_str + c, tokens)
        temp_str << c
      else
        maybe_token, temp_str = reset_state(maybe_token, temp_str)
      end
    else
      if(is_token_prefix?(c, tokens))
        maybe_token = true
        temp_str << c
        if is_token?(temp_str, tokens)  
          maybe_token, temp_str = reset_state(maybe_token, temp_str)
          results << buffer
          buffer = ""
        end
      else
        buffer << c
      end
    end
  end
  results << buffer
  results
end

def reset_state(maybe_token, temp_str)
  temp_str=""
  maybe_token = false
  return maybe_token, temp_str
end

def is_token_prefix?(prefix, tokens)
  tokens.each { |token| return true if token.start_with?(prefix) }
  false
end

def is_token?(str, tokens)
  tokens.each { |token| return true if token == str }
  false
end


puts multi_split("dogxycat", ["og", "y"]).to_s
puts multi_split('ddxy', ['d']).to_s
#puts multi_split('ddxy', ['d']) == ['', '', 'xy']
#puts multi_split('dogxycat', ['og', 'y']) == ['d', 'x', 'cat']