if -1 == find( str, re( r"(f)(o*)" ), m) : echo "false"
need to use the find one in import std/nre instead
import std/nre
var
str = "foo"
let mat = find( str, re( r"(f)(o*)" ))
if isNone(mat): echo "false"
else:
echo "m" & mat.get.captures[1]
You can discover the data type yourself using something like
echo(type(mat))
eventually taking advantage of wonderful Nim's playground