diff --git a/src/nasal_type.cpp b/src/nasal_type.cpp
index 8a38b11..561f68c 100644
--- a/src/nasal_type.cpp
+++ b/src/nasal_type.cpp
@@ -6,22 +6,6 @@
 
 namespace nasal {
 
-var nas_vec::get_value(const i32 index) {
-    i32 size = elems.size();
-    if (index<-size || index>=size) {
-        return var::none();
-    }
-    return elems[index>=0? index:index+size];
-}
-
-var* nas_vec::get_memory(const i32 index) {
-    i32 size = elems.size();
-    if (index<-size || index>=size) {
-        return nullptr;
-    }
-    return &elems[index>=0? index:index+size];
-}
-
 std::ostream& operator<<(std::ostream& out, nas_vec& vec) {
     if (!vec.elems.size() || vec.printed) {
         out << (vec.elems.size()? "[..]":"[]");
@@ -40,7 +24,8 @@ std::ostream& operator<<(std::ostream& out, nas_vec& vec) {
 var nas_hash::get_value(const std::string& key) {
     if (elems.count(key)) {
         return elems.at(key);
-    } else if (!elems.count("parents")) {
+    }
+    if (!elems.count("parents")) {
         return var::none();
     }
 
@@ -63,7 +48,8 @@ var nas_hash::get_value(const std::string& key) {
 var* nas_hash::get_memory(const std::string& key) {
     if (elems.count(key)) {
         return &elems.at(key);
-    } else if (!elems.count("parents")) {
+    }
+    if (!elems.count("parents")) {
         return nullptr;
     }
 
@@ -279,12 +265,6 @@ void nas_val::clear() {
     }
 }
 
-f64 var::to_num() const {
-    return type != vm_type::vm_str
-        ? val.num
-        : util::str_to_num(str().c_str());
-}
-
 std::string var::to_str() {
     if (type==vm_type::vm_str) {
         return str();
diff --git a/src/nasal_type.h b/src/nasal_type.h
index 3c240d5..fb283ed 100644
--- a/src/nasal_type.h
+++ b/src/nasal_type.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "nasal.h"
+#include "util/util.h"
 
 #include <cstring>
 #include <sstream>
@@ -173,8 +174,13 @@ public:
     bool is_map() const { return type == vm_type::vm_map; }
 
 public:
-    // number and string can be translated to each other
-    f64 to_num() const;
+    // convert to number
+    f64 to_num() const {
+        return type != vm_type::vm_str
+            ? val.num
+            : util::str_to_num(str().c_str());
+    }
+    // convert to string
     std::string to_str();
     inline bool object_check(const std::string&) const;
     friend std::ostream& operator<<(std::ostream&, var&);
@@ -187,8 +193,20 @@ struct nas_vec {
     bool printed = false;
 
     auto size() const { return elems.size(); }
-    var get_value(const i32);
-    var* get_memory(const i32);
+    var get_value(const i32 index) {
+        i32 size = elems.size();
+        if (index < -size || index >= size) {
+            return var::none();
+        }
+        return elems[index >= 0 ? index : index + size];
+    }
+    var* get_memory(const i32 index) {
+        i32 size = elems.size();
+        if (index < -size || index >= size) {
+            return nullptr;
+        }
+        return &elems[index >= 0 ? index : index + size];
+    }
     friend std::ostream& operator<<(std::ostream&, nas_vec&);
 };
 
diff --git a/src/nasal_vm.h b/src/nasal_vm.h
index 62c1f87..312d031 100644
--- a/src/nasal_vm.h
+++ b/src/nasal_vm.h
@@ -97,6 +97,7 @@ protected:
 protected:
     /* vm calculation functions*/
     inline bool boolify(const var&);
+    inline void set_frame(const nas_func&, var*);
 
 protected:
     /* vm operands */
@@ -342,6 +343,15 @@ inline bool vm::boolify(const var& val) {
     return false;
 }
 
+inline void vm::set_frame(const nas_func& func, var* local) {
+    ctx.top[0] = ctx.upvalr;
+    (++ctx.top)[0] = var::addr(ctx.localr);
+    (++ctx.top)[0] = var::ret(ctx.pc); // rewrite top with vm_ret
+    ctx.pc = func.entry - 1;
+    ctx.localr = local;
+    ctx.upvalr = nil;
+}
+
 inline void vm::o_repl() {
     // reserved for repl mode stack top value output
     if (allow_repl_output) {
@@ -935,12 +945,7 @@ inline void vm::o_callfv() {
             ? parameter_size + 1
             : func.local_size - 1] = dynamic;
 
-    ctx.top[0] = ctx.upvalr;
-    (++ctx.top)[0] = var::addr(ctx.localr);
-    (++ctx.top)[0] = var::ret(ctx.pc);
-    ctx.pc = func.entry-1;
-    ctx.localr = local;
-    ctx.upvalr = nil;
+    set_frame(func, local);
 }
 
 inline void vm::o_callfh() {
@@ -987,12 +992,7 @@ inline void vm::o_callfh() {
         return;
     }
 
-    ctx.top[0] = ctx.upvalr;
-    (++ctx.top)[0] = var::addr(ctx.localr);
-    (++ctx.top)[0] = var::ret(ctx.pc); // rewrite top with vm_ret
-    ctx.pc=func.entry-1;
-    ctx.localr = local;
-    ctx.upvalr = nil;
+    set_frame(func, local);
 }
 
 inline void vm::o_callb() {
diff --git a/src/natives/dylib_lib.cpp b/src/natives/dylib_lib.cpp
index d405974..61e1002 100644
--- a/src/natives/dylib_lib.cpp
+++ b/src/natives/dylib_lib.cpp
@@ -18,35 +18,64 @@ void dynamic_library_destructor(void* pointer) {
 #endif
 }
 
+std::vector<std::string> possible_dylib_path() {
+    const auto env_path = std::string(getenv("PATH"));
+    const auto sep = (util::is_windows()? ";":":");
+    const auto path_front = util::is_windows()? "\\module\\":"/module/";
+
+    // do split string
+    std::vector<std::string> env_path_vec = {"."};
+    usize last = 0;
+    usize pos = env_path.find(sep, 0);
+    while(pos != std::string::npos) {
+        if (pos > last) {
+            env_path_vec.push_back(env_path.substr(last, pos - last));
+        }
+        last = pos + 1;
+        pos = env_path.find(sep, last);
+    }
+    if (last != env_path.length()) {
+        env_path_vec.push_back(env_path.substr(last));
+    }
+
+    for (auto& p : env_path_vec) {
+        p += path_front;
+    }
+
+    return env_path_vec;
+}
+
 std::string search_dynamic_library_path(const std::string& dlname) {
     const auto ext = (util::is_windows()? ".dll":".so");
     const auto lib_path = (util::is_windows()? ".\\":"./") + dlname + ext;
     if (fs::exists(lib_path)) {
         return lib_path;
     }
-    const auto env_path = std::string(getenv("PATH"));
-    const auto sep = (util::is_windows()? ";":":");
-
-    // do split string
-    std::vector<std::string> env_path_vec = {"."};
-    usize last = 0;
-    usize pos = env_path.find(sep, 0);
-    while(pos!=std::string::npos) {
-        if (pos>last) {
-            env_path_vec.push_back(env_path.substr(last, pos-last));
+    // macos may use .dylib as extension
+    if (util::is_macos()) {
+        const auto dylib_path = "./" + dlname + ".dylib";
+        if (fs::exists(dylib_path)) {
+            return dylib_path;
         }
-        last = pos + 1;
-        pos = env_path.find(sep, last);
-    }
-    if (last!=env_path.length()) {
-        env_path_vec.push_back(env_path.substr(last));
     }
 
-    const auto path_front = util::is_windows()? "\\module\\":"/module/";
-    for(auto& p : env_path_vec) {
-        p += path_front + lib_path;
-        if (fs::exists(p)) {
-            return p;
+    // search library in PATH
+    const auto possible_path = possible_dylib_path();
+    for(const auto& p : possible_path) {
+        const auto env_p = p + lib_path;
+        if (fs::exists(env_p)) {
+            return env_p;
+        }
+    }
+
+    // macos may use .dylib as extension
+    if (util::is_macos()) {
+        const auto dylib_path = "./" + dlname + ".dylib";
+        for(const auto& p : possible_path) {
+            const auto env_p = p + dylib_path;
+            if (fs::exists(env_p)) {
+                return env_p;
+            }
         }
     }
     return "";
@@ -61,7 +90,7 @@ var builtin_dlopen(context* ctx, gc* ngc) {
     const auto dlname = search_dynamic_library_path(dl.str());
     if (dlname.empty()) {
         return nas_err("dylib::dlopen",
-            "cannot find dynamic lib <" + dl.str() + ">"
+            "cannot find dynamic library <" + dl.str() + ">"
         );
     }
 
diff --git a/src/natives/dylib_lib.h b/src/natives/dylib_lib.h
index 67a9ef0..c4ae80f 100644
--- a/src/natives/dylib_lib.h
+++ b/src/natives/dylib_lib.h
@@ -13,11 +13,13 @@
 
 #include <cstring>
 #include <sstream>
+#include <vector>
 
 namespace nasal {
 
 void dynamic_library_destructor(void*);
 
+std::vector<std::string> possible_dylib_path();
 std::string search_dynamic_library_path(const std::string&);
 
 var builtin_dlopen(context*, gc*);