The version of GNU Bison on my mac is 2.3 but I know that Bison 2.5 was released long ago. The book Flex & Bison uses version 2.5.
Should I upgrade to 2.5 myself? Is it necessary?
What's the difference between 2.3 and 2.5?
I had the same issue MacOSX 10.9.5.
After doing:
brew install bison
I added this to my bash profile:
export PATH=/usr/local/Cellar/bison/3.0.4/bin:$PATH
(by the time you read this, your version may be different from 3.0.4)
And after I restarted the Terminal it picked up the new version of Bison when I did bison -V