ragel_lexer.rb

=begin
%%{

  machine simple_lexer;
  
  integer     = ('+'|'-')?[0-9]+;
  float       = ('+'|'-')?[0-9]+'.'[0-9]+;
  assignment  = '=';
  identifier  = [a-zA-Z][a-zA-Z_]+; 
  
  main := |*
    
    integer => { 
      emit(:integer_literal, data, token_array, ts, te) 
    };
    
    float => { 
      emit(:float_literal, data, token_array, ts, te) 
    };
    
    assignment => { 
      emit(:assignment_operator, data, token_array, ts, te) 
    };
    
    identifier => { 
      emit(:identifier, data, token_array, ts, te) 
    };
    
    space;
    
  *|;

}%%
=end

%% write data;
# %% this just fixes our syntax highlighting...

def emit(token_name, data, target_array, ts, te)
  target_array << {:name => token_name.to_sym, :value => data[ts...te].pack("c*") }
end

def run_lexer(data)
  data = data.unpack("c*") if(data.is_a?(String))
  eof = data.length
  token_array = []
  
  %% write init;
  %% write exec;

  puts token_array.inspect
end

I think you meant to name this file ragel_lexer.rl since it has to be processed by Ragel first. Thanks! Your article over at http://thingsaaronmade.com/blog/a-simple-intro-to-writing-a-lexer-with-ragel.html has been very helpful!