[Flex-devel] Summary of new options I've added

[Joe K. <kr...@ni...>]

I added a special token to allow flex's internal scanner to support 
--options=OPTIONS, where OPTIONS is anything valid in %option.

The modified scan.l also keeps boolean options separate, so that the 
"no" prefix is not silently accepted where it is invalid.

I modified the full/fast options to only set the specific full/fast 
flags, which is in 3 places, because the command-line has individual 
flags and the grouped -C<opt> flag. I then modify useecs, usemecs, and 
use_read in check_options(), but only if the user didn't specify them. 
They are initially set to 'unspecified'.

I added %options to exclude generating the remaining optional functions, 
but didn't make command-line versions.

I added --include="PATH" to define the m4 include path to access 
skeleton files, and a matching one-letter option "-Y" which Sun's lex 
uses. Maybe the long option should be --skel-path=PATH. The main 
skeleton file is also expected to be there, but it checks the current 
directory first.

The %option noline was missing, possibly removed because #line marks 
could be inserted before that option was read. I fixed this by modifying 
the linedir filter function to remove any #lines when noline is active, 
and added noline back to scan.l.

I modified the prefix option to remove leading underscores if the prefix 
is blank.

I added a yynamespace option for compiling the C scanner as C++, which 
can be used with a blank prefix, giving yy::lex() as the lexer function, 
for example.