Before this change, the start rule was the one named "start" and there
was an option to override that. This is now impossible.
The goal of this change is to contain all information for the parser
generation in the grammar itself.
In the future, some override directive for the start rule (like Bison's
"%start") may be added to the grammar.
This and also speeds up the benchmark suite execution by 7.83 % on V8.
Detailed results (benchmark suite totals):
---------------------------------
Test # Before After
---------------------------------
1 26.17 kB/s 28.16 kB/s
2 26.05 kB/s 28.16 kB/s
3 25.99 kB/s 28.10 kB/s
4 26.13 kB/s 28.11 kB/s
5 26.14 kB/s 28.07 kB/s
---------------------------------
Average 26.10 kB/s 28.14 kB/s
---------------------------------
Mozilla/5.0 (X11; U; Linux i686; en-US) AppleWebKit/533.2 (KHTML, like Gecko) Chrome/5.0.342.7 Safari/533.2
Until now, these tasks looked at the file times and generated the target files
only when they were older than the source files. This caused problems when I
mainupulated the lib/metagrammar.* files by hand sometimes, replaced them from
backups after screw-ups, etc.
