calling lua from clojure

lua.clj

(ns liblua-clj.lua
  (:require
    [tech.v3.datatype.ffi :as dt-ffi]))

(set! *warn-on-reflection* true)

(def lua-def
  {:luaL_newstate {:rettype :pointer
                   :argtypes []}
   :luaL_openlibs {:rettype :void
                   :argtypes [['ls :pointer]]}
   ;; XXX: macros don't work
   ;; :luaL_dostring {:rettype :int16
   ;;                 :argtypes [['ls :pointer]
   ;;                            ['code :string]]}
   :luaL_loadstring {:rettype :int16
                     :argtypes [['ls :pointer]
                                ['code :string]]}
   ;; XXX: lua_pcall not found...
   :lua_pcallk {:rettype :int16
               :argtypes [['ls :pointer]
                          ['nargs :int16]
                          ['nresults :int16]
                          ['msgh :int16]]}
   :lua_close {:rettype :void
               :argtypes [['ls :pointer]]}})

(defonce lua
  (dt-ffi/library-singleton #'lua-def))

(dt-ffi/library-singleton-reset! lua)

(defn set-library-instance!
  [lib-instance]
  (dt-ffi/library-singleton-set-instance! lua lib-instance))

(defn initialize!
  []
  (dt-ffi/library-singleton-set! lua "lua"))

(defn find-fn
  [fn-name]
  (dt-ffi/library-singleton-find-fn lua fn-name))

(dt-ffi/define-library-functions
  liblua-clj.lua/lua-def find-fn nil)

(comment

  (initialize!)
  ;; => #object[tech.v3.datatype.ffi.jna.G__7824 0x70f8d5f8 {:status :ready, :val {:lua_pcallk #object[tech.v3.datatype.ffi.jna.G__7824$invoker_lua_pcallk 0x3bdfaa63 "tech.v3.datatype.ffi.jna.G__7824$invoker_lua_pcallk@3bdfaa63"], :luaL_loadstring #object[tech.v3.datatype.ffi.jna.G__7824$invoker_luaL_loadstring 0x46d4d407 "tech.v3.datatype.ffi.jna.G__7824$invoker_luaL_loadstring@46d4d407"], :luaL_newstate #object[tech.v3.datatype.ffi.jna.G__7824$invoker_luaL_newstate 0x6baf6f4a "tech.v3.datatype.ffi.jna.G__7824$invoker_luaL_newstate@6baf6f4a"], :lua_close #object[tech.v3.datatype.ffi.jna.G__7824$invoker_lua_close 0x57156620 "tech.v3.datatype.ffi.jna.G__7824$invoker_lua_close@57156620"], :luaL_openlibs #object[tech.v3.datatype.ffi.jna.G__7824$invoker_luaL_openlibs 0x409324e6 "tech.v3.datatype.ffi.jna.G__7824$invoker_luaL_openlibs@409324e6"]}}]
  
  (def ls
    (luaL_newstate))
  ;; => #'liblua-clj.lua/ls

  (luaL_openlibs ls)
  ;; => nil

  (luaL_loadstring ls
                   (str "f = io.open(\"/tmp/lua-test.txt\", \"w\")\n"
                        "f:write(\"smile!\")\n"
                        "f:close()\n"))
  ;; => 0

  (def LUA_MULTRET -1)
  ;; => #'liblua-clj.lua/LUA_MULTRET
  
  (lua_pcallk ls 0 LUA_MULTRET 0)
  ;; => 0

  (print (slurp "/tmp/lua-test.txt"))
  ;; => nil
  
  (lua_close ls)
  ;; => nil

  )