Speaking as the author, I too wish it was written in Rust. But, I started it in 2007 when I needed to get practice with C++ for work. At this point, there's so much code in lnav, rewriting would be a long process. There are some sub-components[1] that are written in Rust though.

A new project called logana[2] is written in Rust and is headed in a good direction. Use/contribute to that if you're really interested.

[1] - https://github.com/tstack/lnav/tree/master/src/third-party/l...

[2] - https://github.com/pauloremoli/logana/

How would this improve the functionality of lnav?

I sense an opportunity for you.