> I'm not totally clear on what kind of filtering `rak` does by default
By default, rak search all of the files that look like text, by reading the first 2K (if I remember correctly) and using some algorithm to determine "binaryness".
> I realize features and an expressive language is your main goal
Indeed.
> I wanted to see what it looked like from a perf perspective
The performance times you've given here, coincide with my findings. Which for the "sixteenth.txt" surprises me: a bare loop in Raku reading that file line-by-line finishes in 8 seconds for me. Which would be one order of magnitude less than the search result. Still not in `rg`'s ball park, but speed wasn't a big concern for me. But 8 -> 48 seconds is a pretty big difference, so I guess it's back to the drawing board for me on that one :-)