I have a simple rule in my grammar which looks for sequence of whitespaces:
ws: ws|' ';
When bison sees this rule, it complains:
warning: rule useless in parser due to conflicts: ws: ws
Why it is so? Cant I have a simple rule in grammar which looks for a regex?
what you are declaring is 'ws is ws or ws is a space', not 'ws is one or more spaces'.
If you want the latter, try something like:
ws: ' '
| ' ' ws;
See also http://www.gnu.org/software/bison/manual/bison.html#Recursion
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.