While we are thinking about this, I suggest we remove (later) the rule forbidding backing-up states in the scanner. It made only a 0.2% in the worst-case scenario I could think of.
The rule had been violated, giving us the slightly slower scanner, for about ten years (I estimate) prior to the warning-cleanup patch da949cdc one year ago. It costs a lot of programmer time to make the extra rules to save that 0.2%, and I know of no efficient cure for patterns that can require arbitrary amounts of backing up. \violin1_2_3_4_5 http://codereview.appspot.com/6493072/diff/5015/lily/lexer.ll File lily/lexer.ll (left): http://codereview.appspot.com/6493072/diff/5015/lily/lexer.ll#oldcode34 lily/lexer.ll:34: flex -b <this lexer file> `-b, --backup, `%option backup'' Generate backing-up information to `lex.backup'. This is a list of scanner states which require backing up and the input characters on which they do so. By adding rules one can remove backing-up states. If _all_ backing-up states are eliminated and `-Cf' or `-CF' is used, the generated scanner will run faster (see the `--perf-report' flag). Only users who wish to squeeze every last cycle out of their scanners need worry about this option. (*note Performance::). http://codereview.appspot.com/6493072/ _______________________________________________ lilypond-devel mailing list lilypond-devel@gnu.org https://lists.gnu.org/mailman/listinfo/lilypond-devel
