bug#29909: non-greedy matching (RE2)

[Shawn Landden]

It is well known that sed lacks non-greedy regular expression matches.
This means that sed can only match a subset of regular languages[1].
Would a proper patch to add re2 support[2], so that sed implements ALL
regular languages correctly, in O(n) time, be considered?

Thanks,

Shawn Landden

[1] 
https://en.wikipedia.org/wiki/Regular_language#Location_in_the_Chomsky_hierarchy
And because that link isn't very good, 28c3: The Science of Insecurity
https://www.youtube.com/watch?v=3kEfedtQVOY
[2] https://github.com/google/re2