tokenizing

2+4 + a6 +3

java Main sample.input

token 0: type: 1, text: 2
token 1: type: 2, text: +
token 2: type: 1, text: 4
token 3: type: 2, text:  
token 4: type: 2, text: +
token 5: type: 2, text:  
token 6: type: 2, text: a
token 7: type: 1, text: 6
token 8: type: 2, text:  

%%

%{
  private int comment_count = 0;
  public static void trace(String msg) {
  System.out.println(msg);
  }

  public Yytoken t(int type, String text) {
    return new Yytoken(type, text);
  }

%} 

%line
%char
%full


//%debug

DIGIT=[0-9]

%% 

{DIGIT} { return t(1, yytext());}


<<EOF>> {return t(-1, "eof"); }

. {
  return t(2, yytext() );
  }

public class Main {

  public static void main(String argv[]) throws Exception {
	  if (argv.length <1) {
		  System.out.println("Usage: HelloMain file");
		  return;
	  } 
        Yylex scanner = null;
          scanner = new Yylex( new java.io.FileReader(argv[0]) );
	  for(int i=0; i<9; i++) {

            System.out.println("token "+i+": "+scanner.yylex());
          } 

  }

}