PPT Slide

// Parse slash-delimited book data.

%class lex

%standalone

%unicode

%line

%column

%char

LineTerminator = \r|\n|\r\n

Slash = "/"

Field = [^/\r\n]+

Title = \"[^/\r\n]+\"

StringBuffer line;

private void initialize_buffer(String s) {

int adjusted_line_no = yyline + 1;

line = new StringBuffer("[" + adjusted_line_no + "] " + s);

}

private void add_identifier_to_buffer(String s) {

line.append(s);

}

private void add_delimiter_to_buffer(String s) {

line.append(s);

}

private void display_line() {

System.out.println(line.toString());

}

private void wrap_up() {

System.out.println("Lines Processed: " + yyline);

System.out.println("Total Number of Characters: " + yychar);

}

{Title} { initialize_buffer(yytext()); }

{Field} { add_identifier_to_buffer(yytext()); }

{Slash} { add_delimiter_to_buffer("/"); }

{LineTerminator} { display_line(); }

<<EOF>> { wrap_up(); return 0; }

Turn on

character

counting

When the lexer hits the end of file

we call this wrap_up method to

print the number of lines and the

total number of characters in the

input file.

See example05