r3.nim

type
  TR3Node {.importc: "node", header: "<r3/r3.h>".} = object 
    data: pointer  

proc r3_tree_create(size: int): ptr TR3Node 
  {.importc, dynlib: "libr3.so"}
proc r3_tree_insert_path(node: ptr TR3Node, path: cstring, data: pointer) 
  {.importc, header: "<r3/r3.h>".}
proc r3_tree_compile(node: ptr TR3Node, err: ptr cstring): int 
  {.importc, dynlib: "libr3.so".}
proc r3_tree_dump(node: ptr TR3Node, depth: int) 
  {.importc, dynlib: "libr3.so".}
proc r3_tree_match(node: ptr TR3Node, path: cstring, entry: ptr object): ptr TR3Node 
  {.importc, header: "<r3/r3.h>".}

let n = r3_tree_create(10)

var 
  callback = proc () =
    echo "called"

r3_tree_insert_path(n, "/users/{id}", addr(callback))

var errstr: ptr cstring
let err = r3_tree_compile(n, errstr)
if err != 0:
  echo errstr[]

r3_tree_dump(n, 0)

var node = r3_tree_match(n, "/users/1", nil)
if node != nil:
  var cb: ref proc () = cast[ref proc ()](node.data)
  cb[]()