PPT Slide

boolean at_start = true;

private void print_root_start_tag(String s) {

if (at_start) {

System.out.print("<" + s + ">");

at_start = false;

}

}

private void print_root_end_tag(String s) {

System.out.print("</" + s + ">");

}

...

%}

%%

{Title} { print_root_start_tag("BookCatalogue");

print_start_tag("Book");

print_start_tag("Title");

print_element_data(yytext());

print_end_tag("Title");

}

{Field} { print_start_tag("Field");

print_element_data(yytext());

print_end_tag("Field");

}

{Slash} { print_new_line(); }

{LineTerminator} { print_end_tag("Book");

print_new_line();

}

<<EOF>> { print_root_end_tag("BookCatalogue");

return 0;

}

At every Title we invoke this method.

However, this method only does the

output the first time it's invoked.

Output:

<BookCatalogue>

<Book>

<Title>"My Life and Times"</Title>

<Field>Paul McCartney</Field>

<Field>July, 1998</Field>

<Field�-12021-43892</Field>

<Field>McMillin Publishing</Field>

</Book>

<Book>

<Title>"Illusions…"</Title>

<Field>Richard Bach</Field>

…

</Book>

…

</BookCatalogue>

mylexer.flex

See example08

Do Lab7

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