None sounds a bit selfish. Understandable, but not realistic.

No single product (or module) in the public domain is written for just one single user. If it were, it would not be on CPAN. There are no two users that are identical, not even me myself and I.

As a module author I somehow expect that the author of CPAN modules do try to minimize performance penalties. Always. So "as little as possible" is - to me - an "of course".

The balance I am finding is my prediction in how people/user will need the new feature in the future. My reading of the responses, conversations with other developers and reading comments on related OpenSource projects have made me to decide this is the only way forward.

A performance hit of less than 5% is acceptable if I open the usability to a new group that up till now was forced to use slower parsers. The new code performs quite well. The cache code has been simplified and only got me marginal changes: ± 1%, which I interpret as noise.

I've been testing with 5.6.1 through 5.21.1 over this weekend and all looks pretty well. Only perl built with strict clang currently fails. I will need to address this before I release.

Thank all for the valuable feedback.