diff --git a/makefile b/makefile
index fae646d8c..5c3360d18 100644
--- a/makefile
+++ b/makefile
@@ -190,10 +190,13 @@ build-mk:
 	cd build && make -j16 build_z3_ocaml_bindings
 .PHONY:build
 
-# /bin/sh: 1: ocamlfind ocamlc -where: not found
+build-nj:
+	cd build && ninja
+.PHONY:build-nj
+
 build:
 	cd build && ninja build_z3_ocaml_bindings
-.PHONY:build-nj
+.PHONY:build
 
 dot:
 	cd build && dot -Tpng -o deps.png deps.dot
diff --git a/src/api/ml/CMakeLists.txt b/src/api/ml/CMakeLists.txt
index 71902f820..5cd31d444 100644
--- a/src/api/ml/CMakeLists.txt
+++ b/src/api/ml/CMakeLists.txt
@@ -1,6 +1,3 @@
-###############################################################################
-# Install
-###############################################################################
 find_package(OCaml REQUIRED)
 
 set(exe_ext ${CMAKE_EXECUTABLE_SUFFIX})
@@ -13,7 +10,7 @@ set(z3ml_bin ${CMAKE_CURRENT_BINARY_DIR})
 if (Z3_BUILD_OCAML_EXTERNAL_LIBZ3)
   add_custom_target(libz3_z3ml
     ALL
-    DEPENDS "${Z3_BUILD_OCAML_EXTERNAL_LIBZ3}/libz3${so_ext}"
+    DEPENDS ${Z3_BUILD_OCAML_EXTERNAL_LIBZ3}/libz3${so_ext}
   )
   set(libz3_path ${Z3_BUILD_OCAML_EXTERNAL_LIBZ3})
 else()
@@ -24,13 +21,11 @@ else()
   set(libz3_path ${PROJECT_BINARY_DIR})
 endif()
 
-set(Z3ml_native_stubs_c "${z3ml_bin}/z3native_stubs.c")
-
 add_custom_command(
   OUTPUT
-    "${z3ml_bin}/z3native.ml"
-    ${Z3ml_native_stubs_c}
-  COMMAND "${PYTHON_EXECUTABLE}"
+    ${z3ml_bin}/z3native.ml
+    ${z3ml_bin}/z3native_stubs.c
+  COMMAND "${Python3_EXECUTABLE}"
     "${PROJECT_SOURCE_DIR}/scripts/update_api.py"
     ${Z3_FULL_PATH_API_HEADER_FILES_TO_SCAN}
     "--ml-src-dir"
@@ -38,37 +33,36 @@ add_custom_command(
     "--ml-output-dir"
     "${CMAKE_CURRENT_BINARY_DIR}"
   DEPENDS
+    ${PROJECT_SOURCE_DIR}/scripts/update_api.py
     ${Z3_FULL_PATH_API_HEADER_FILES_TO_SCAN}
-    "${PROJECT_SOURCE_DIR}/scripts/update_api.py"
     ${Z3_GENERATED_FILE_EXTRA_DEPENDENCIES}
-  COMMENT "Generatinging ${z3ml_bin}/z3native.ml and ${Z3ml_native_stubs_c}"
+  COMMENT "Generatinging ${z3ml_bin}/z3native.ml and ${z3ml_bin}/z3native_stubs.c"
   VERBATIM
 )
 
-set(gen_z3enum "${z3ml_bin}/z3enums.ml")
 add_custom_command(
   OUTPUT 
-    ${gen_z3enum}
-  COMMAND "${PYTHON_EXECUTABLE}"
+    ${z3ml_bin}/z3enums.ml
+  COMMAND "${Python3_EXECUTABLE}"
     "${PROJECT_SOURCE_DIR}/scripts/mk_consts_files.py"
     ${Z3_FULL_PATH_API_HEADER_FILES_TO_SCAN}
     "--ml-output-dir"
     "${CMAKE_CURRENT_BINARY_DIR}"
   DEPENDS
+    ${PROJECT_SOURCE_DIR}/scripts/mk_consts_files.py
     ${Z3_FULL_PATH_API_HEADER_FILES_TO_SCAN}
-    "${PROJECT_SOURCE_DIR}/scripts/mk_consts_files.py"
     ${Z3_GENERATED_FILE_EXTRA_DEPENDENCIES}
-  COMMENT "Generating ${gen_z3enum}"
+  COMMENT "Generating ${z3ml_bin}/z3enums.ml"
   VERBATIM
 )
 
 add_custom_command(
-  OUTPUT  "${z3ml_bin}/z3.ml"
-          "${z3ml_bin}/z3.mli"
+  OUTPUT  ${z3ml_bin}/z3.ml
+          ${z3ml_bin}/z3.mli
   COMMAND "${CMAKE_COMMAND}" "-E" "copy" "${z3ml_src}/z3.ml" "${z3ml_bin}/z3.ml"
   COMMAND "${CMAKE_COMMAND}" "-E" "copy" "${z3ml_src}/z3.mli" "${z3ml_bin}/z3.mli"
-  DEPENDS "${z3ml_src}/z3.ml"
-          "${z3ml_src}/z3.mli"
+  DEPENDS ${z3ml_src}/z3.ml
+          ${z3ml_src}/z3.mli
   COMMENT "Copying z3.ml and z3.mli to build area")
 
 set(z3ml_common_flags  "-package" "zarith"
@@ -88,17 +82,16 @@ add_custom_command(
           "-I" "${PROJECT_SOURCE_DIR}/src/api"
           "-I" "${ocaml_stub_lib_path}"
           "-c" "${z3ml_bin}/z3native_stubs.c"
-  DEPENDS ${Z3ml_native_stubs_c}
+  DEPENDS ${z3ml_bin}/z3native_stubs.c
   COMMENT "Building z3native_stubs.o"
   VERBATIM)
 
 # z3enum.ml depends on nothing
-
 add_custom_command(
-  OUTPUT "${z3ml_bin}/z3enums.mli"
-         "${z3ml_bin}/z3enums.cmi"
-         "${z3ml_bin}/z3enums.cmo"
-         "${z3ml_bin}/z3enums.cmx"
+  OUTPUT ${z3ml_bin}/z3enums.mli
+         ${z3ml_bin}/z3enums.cmi
+         ${z3ml_bin}/z3enums.cmo
+         ${z3ml_bin}/z3enums.cmx
   COMMAND "${OCAMLFIND}" "ocamlc"   ${z3ml_common_flags}
          "-i" 
          "-c" "${z3ml_bin}/z3enums.ml"
@@ -109,17 +102,16 @@ add_custom_command(
          "-c" "${z3ml_bin}/z3enums.ml"
   COMMAND "${OCAMLFIND}" "ocamlopt" ${z3ml_common_flags}
           "-c" "${z3ml_bin}/z3enums.ml"
-  DEPENDS ${gen_z3enum}
+  DEPENDS ${z3ml_bin}/z3enums.ml
   COMMENT "Building z3enums.{mli,cmi,cmo,cmx}"
   VERBATIM)
 
 # z3native.ml depends on z3enums
-
 add_custom_command(
-  OUTPUT "${z3ml_bin}/z3native.mli"
-         "${z3ml_bin}/z3native.cmi"
-         "${z3ml_bin}/z3native.cmo"
-         "${z3ml_bin}/z3native.cmx"
+  OUTPUT ${z3ml_bin}/z3native.mli
+         ${z3ml_bin}/z3native.cmi
+         ${z3ml_bin}/z3native.cmo
+         ${z3ml_bin}/z3native.cmx
   COMMAND "${OCAMLFIND}" "ocamlc"   ${z3ml_common_flags}
          "-i" 
          "-c" "${z3ml_bin}/z3native.ml"
@@ -130,30 +122,30 @@ add_custom_command(
           "-c" "${z3ml_bin}/z3native.ml"
   COMMAND "${OCAMLFIND}" "ocamlopt" ${z3ml_common_flags}
           "-c" "${z3ml_bin}/z3native.ml"
-  DEPENDS "${z3ml_bin}/z3enums.cmo"
-          "${z3ml_bin}/z3native.ml"
+  DEPENDS ${z3ml_bin}/z3enums.cmo
+          ${z3ml_bin}/z3native.ml
   COMMENT "Building z3native.{mli,cmi,cmo,cmx}"
   VERBATIM)
 
 # z3.ml depends on z3enums and z3native
-
 add_custom_command(
-  OUTPUT "${z3ml_bin}/z3.cmi"
-         "${z3ml_bin}/z3.cmo"
-         "${z3ml_bin}/z3.cmx"
+  OUTPUT ${z3ml_bin}/z3.cmi
+         ${z3ml_bin}/z3.cmo
+         ${z3ml_bin}/z3.cmx
   COMMAND "${OCAMLFIND}" "ocamlc"   ${z3ml_common_flags}
           "-c" "${z3ml_bin}/z3.mli"
   COMMAND "${OCAMLFIND}" "ocamlc"   ${z3ml_common_flags}
           "-c" "${z3ml_bin}/z3.ml"
   COMMAND "${OCAMLFIND}" "ocamlopt" ${z3ml_common_flags}
           "-c" "${z3ml_bin}/z3.ml" 
-  DEPENDS "${z3ml_bin}/z3enums.cmo"
-          "${z3ml_bin}/z3native.cmo"
-          "${z3ml_bin}/z3.ml"
-          "${z3ml_bin}/z3.mli"
+  DEPENDS ${z3ml_bin}/z3enums.cmo
+          ${z3ml_bin}/z3native.cmo
+          ${z3ml_bin}/z3.ml
+          ${z3ml_bin}/z3.mli
   COMMENT "Building z3.cmo"
   VERBATIM)
 
+# making ocaml stublibs  
 execute_process(
   COMMAND ${OCAMLFIND} printconf destdir
   OUTPUT_VARIABLE ocaml_destdir_path
@@ -173,37 +165,119 @@ set(ocamlmklib_flags "-o" "z3ml"
                      "-I" "${z3ml_bin}")
 
 add_custom_command(
-  OUTPUT "${z3ml_bin}/dllz3ml${so_ext}"
-         "${z3ml_bin}/libz3ml.a"
-         "${z3ml_bin}/z3ml.cma"
-         "${z3ml_bin}/z3ml.cmxa"
-         "${z3ml_bin}/z3ml.cmxs"
+  OUTPUT ${z3ml_bin}/dllz3ml${so_ext}
+         ${z3ml_bin}/libz3ml.a
+         ${z3ml_bin}/z3ml.cma
+         ${z3ml_bin}/z3ml.cmxa
+         ${z3ml_bin}/z3ml.cmxs
   COMMAND "${OCAMLFIND}" "ocamlmklib" ${ocamlmklib_flags}
-    "${z3ml_bin}/z3enums.cmo"
-    "${z3ml_bin}/z3native.cmo"
-    "${z3ml_bin}/z3native_stubs.o"
-    "${z3ml_bin}/z3.cmo"
+          "${z3ml_bin}/z3enums.cmo"
+          "${z3ml_bin}/z3native.cmo"
+          "${z3ml_bin}/z3native_stubs.o"
+          "${z3ml_bin}/z3.cmo"
   COMMAND "${OCAMLFIND}" "ocamlmklib" ${ocamlmklib_flags}
-    "${z3ml_bin}/z3enums.cmx"
-    "${z3ml_bin}/z3native.cmx"
-    "${z3ml_bin}/z3native_stubs.o"
-    "${z3ml_bin}/z3.cmx"
+          "${z3ml_bin}/z3enums.cmx"
+          "${z3ml_bin}/z3native.cmx"
+          "${z3ml_bin}/z3native_stubs.o"
+          "${z3ml_bin}/z3.cmx"
   COMMAND "${OCAMLFIND}" "ocamlopt" "-linkall" "-shared"
-    "-o" "${z3ml_bin}/z3ml.cmxs"
-    "-I" "${z3ml_bin}"
-    "${z3ml_bin}/z3ml.cmxa"
+          "-o" "${z3ml_bin}/z3ml.cmxs"
+          "-I" "${z3ml_bin}"
+          "${z3ml_bin}/z3ml.cmxa"
    DEPENDS
-    libz3_z3ml
-    ${z3ml_bin}/z3native_stubs.o
-    "${z3ml_bin}/z3enums.cmo"
-    "${z3ml_bin}/z3native.cmo"
-    "${z3ml_bin}/z3.cmo"
-    "${z3ml_bin}/z3enums.cmx"
-    "${z3ml_bin}/z3native.cmx"
-    "${z3ml_bin}/z3.cmx"
+          libz3_z3ml
+          ${z3ml_bin}/z3native_stubs.o
+          ${z3ml_bin}/z3enums.cmo
+          ${z3ml_bin}/z3native.cmo
+          ${z3ml_bin}/z3.cmo
+          ${z3ml_bin}/z3enums.cmx
+          ${z3ml_bin}/z3native.cmx
+          ${z3ml_bin}/z3.cmx
   COMMENT "Building z3ml.{cma,cmxa,cmxs}, dllz3ml${so_ext}, and libz3ml.a"
   VERBATIM)
 
+###############################################################################
+# Example
+###############################################################################
+ 
+add_custom_command(
+  OUTPUT  ${z3ml_bin}/ml_example.ml
+  COMMAND "${CMAKE_COMMAND}" "-E" 
+          "copy" "${PROJECT_SOURCE_DIR}/examples/ml/ml_example.ml" "${z3ml_bin}/ml_example.ml"
+  DEPENDS ${PROJECT_SOURCE_DIR}/examples/ml/ml_example.ml
+  COMMENT "Copying ml_example.ml to build area")
+
+execute_process(
+  COMMAND ${OCAMLFIND} query zarith
+  OUTPUT_VARIABLE ocaml_pkg_zarith_path
+  OUTPUT_STRIP_TRAILING_WHITESPACE)
+
+add_custom_command(
+  OUTPUT ${z3ml_bin}/ml_example${bc_ext}
+         ${z3ml_bin}/ml_example.bc.log
+  COMMAND "${OCAMLFIND}" "ocamlc"
+    "-o" "${z3ml_bin}/ml_example${bc_ext}"
+    "-package" "zarith"
+    "-I" "+threads"
+    "-I" "${z3ml_bin}"
+    "-dllpath" "${z3ml_bin}"
+    "-I" ${ocaml_stublibs_path}
+    "-dllpath" ${ocaml_stublibs_path}
+    "${ocaml_pkg_zarith_path}/zarith.cma"
+    "${z3ml_bin}/z3ml.cma"
+    "${z3ml_bin}/ml_example.ml"
+  COMMAND 
+    "ocamlrun" "${z3ml_bin}/ml_example${bc_ext}"
+    ">" "${z3ml_bin}/ml_example.bc.log"
+  DEPENDS
+    ${z3ml_bin}/z3ml.cma
+    ${z3ml_bin}/dllz3ml${so_ext}
+    ${z3ml_bin}/ml_example.ml
+  COMMENT "Testing build and run ml_example bytecode"
+  VERBATIM)
+
+add_custom_command(
+  OUTPUT ${z3ml_bin}/ml_example${exe_ext}
+         ${z3ml_bin}/ml_example.log
+  COMMAND "${OCAMLFIND}" "ocamlopt"
+    "-o" "${z3ml_bin}/ml_example${exe_ext}"
+    "-I" "+threads"
+    "-package" "zarith"
+    "-linkpkg"
+    "-I" "${z3ml_bin}"
+    "${z3ml_bin}/z3ml.cmxa"
+    "${z3ml_bin}/ml_example.ml"
+  COMMAND "${z3ml_bin}/ml_example${exe_ext}"
+    ">" "${z3ml_bin}/ml_example.log"
+  DEPENDS
+    ${z3ml_bin}/z3ml.cmxa
+    ${z3ml_bin}/dllz3ml${so_ext}
+    ${z3ml_bin}/ml_example.ml
+  COMMENT "Testing build and run ml_example natively"
+  VERBATIM)
+
+add_custom_target(build_ocaml_example
+  ALL
+  DEPENDS
+    ${z3ml_bin}/ml_example${bc_ext}
+    ${z3ml_bin}/ml_example${exe_ext}
+)
+
+add_custom_target(build_z3_ocaml_bindings
+  ALL
+  DEPENDS
+    ${z3ml_bin}/z3ml.cma
+    ${z3ml_bin}/z3ml.cmxa
+    ${z3ml_bin}/z3ml.cmxs
+    ${z3ml_bin}/dllz3ml${so_ext}
+    ${z3ml_bin}/libz3ml.a
+    build_ocaml_example
+)
+
+###############################################################################
+# Install
+###############################################################################
+
 # Hacky: When the os is APPLE, a fix command will mutate `libz3.dylib` and `dlllibz3.so` inplace.
 # I don't know how to use conditional `COMMAND` nor specify a file dependency for itself
 # Renaming it and back seems a simple solution.
@@ -224,92 +298,4 @@ add_custom_command(
 #     COMMAND mv "${z3ml_bin}/dllz3ml.pre${so_ext}" "${z3ml_bin}/dllz3ml${so_ext}"
 #     DEPENDS "${z3ml_bin}/dllz3ml.pre${so_ext}"
 #   )
-# endif()
-
-###############################################################################
-# Example
-###############################################################################
- 
-add_custom_command(
-  OUTPUT  "${z3ml_bin}/ml_example.ml"
-  COMMAND "${CMAKE_COMMAND}" "-E" 
-          "copy" "${PROJECT_SOURCE_DIR}/examples/ml/ml_example.ml" "${z3ml_bin}/ml_example.ml"
-  DEPENDS "${PROJECT_SOURCE_DIR}/examples/ml/ml_example.ml"
-  COMMENT "Copying ml_example.ml to build area")
-
-execute_process(
-  COMMAND ${OCAMLFIND} query zarith
-  OUTPUT_VARIABLE ocaml_pkg_zarith_path
-  OUTPUT_STRIP_TRAILING_WHITESPACE)
-
-add_custom_command(
-  OUTPUT "${z3ml_bin}/ml_example${bc_ext}"
-         "${z3ml_bin}/ml_example.bc.log"
-  COMMAND "${OCAMLFIND}" "ocamlc"
-    "-o" "${z3ml_bin}/ml_example${bc_ext}"
-    "-package" "zarith"
-    "-I" "+threads"
-    "-I" "${z3ml_bin}"
-    "-dllpath" "${z3ml_bin}"
-    "-I" ${ocaml_stublibs_path}
-    "-dllpath" ${ocaml_stublibs_path}
-    "${ocaml_pkg_zarith_path}/zarith.cma"
-    "${z3ml_bin}/z3ml.cma"
-    "${z3ml_bin}/ml_example.ml"
-  COMMAND 
-    "ocamlrun" "${z3ml_bin}/ml_example${bc_ext}"
-    ">" "${z3ml_bin}/ml_example.bc.log"
-  DEPENDS
-    "${z3ml_bin}/z3ml.cma"
-    "${z3ml_bin}/dllz3ml${so_ext}"
-    "${z3ml_bin}/ml_example.ml"
-  COMMENT "Testing build and run ml_example bytecode"
-  VERBATIM)
-
-add_custom_command(
-  OUTPUT "${z3ml_bin}/ml_example${exe_ext}"
-         "${z3ml_bin}/ml_example.log"
-  COMMAND "${OCAMLFIND}" "ocamlopt"
-    "-o" "${z3ml_bin}/ml_example${exe_ext}"
-    "-I" "+threads"
-    "-package" "zarith"
-    "-linkpkg"
-    "-I" "${z3ml_bin}"
-    "${z3ml_bin}/z3ml.cmxa"
-    "${z3ml_bin}/ml_example.ml"
-  COMMAND "${z3ml_bin}/ml_example${exe_ext}"
-    ">" "${z3ml_bin}/ml_example.log"
-  DEPENDS
-    "${z3ml_bin}/z3ml.cmxa"
-    "${z3ml_bin}/dllz3ml${so_ext}"
-    "${z3ml_bin}/ml_example.ml"
-  COMMENT "Testing build and run ml_example natively"
-  VERBATIM)
-
-add_custom_target(build_ocaml_example
-  ALL
-  DEPENDS
-    "${z3ml_bin}/ml_example${bc_ext}"
-    "${z3ml_bin}/ml_example${exe_ext}"
-)
-
-add_custom_target(build_z3_ocaml_bindings
-  ALL
-  DEPENDS
-    ${gen_z3enum}
-    "${z3ml_bin}/z3enums.mli"
-    ${Z3ml_native_stubs_c}
-    "${z3ml_bin}/z3native.ml"
-    "${z3ml_bin}/z3native.mli"  
-  
-    "${z3ml_bin}/z3ml.cma"
-    "${z3ml_bin}/z3ml.cmxa"
-    "${z3ml_bin}/z3ml.cmxs"
-    "${z3ml_bin}/dllz3ml${so_ext}"
-    "${z3ml_bin}/libz3ml.a"
-    build_ocaml_example
-)
-
-###############################################################################
-# Install
-###############################################################################
+# endif()
\ No newline at end of file