[Flex-devel] Suggestions for improvement

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

I am using Bison's new C++ features with Flex. I did not use the new 
Flex C++ features, because they seem rather incomplete. Instead, I used 
Flex reentrant mode. In the process, I have a few suggestions. Given the 
recent update, I assume there is some active work in this area.

The Flex reentrant version actually works quite well with Bison's C++ 
mode. it just requires a few tricks because Bison has a fixed definition 
for yylex(). I could put together an example, unless Bison C++ users 
would rather have a more complete Flex C++ scanner. OTOH, the flex 
source says "... or omit the C++ scanner altogether.", so maybe a good 
use of reentrant mode is a better goal?

The one problem I had from Flex is that I am generating the output 
header file, which I also include indirectly in my flex source, causing 
several conflicts. When the header is generated, I think it would be 
better not to duplicate everything in the generated source as well, but 
put an include statement in the generated source, perhaps with a #define 
so the header can distinguish external and internal #includes.

Some of the skeleton-file development would be more efficient by using 
external skeleton source files, as Bison does.

Joe Krahn