diff --git a/fcore/core-key.sml b/fcore/core-key.sml
index d20ab95..bec6cfe 100644
--- a/fcore/core-key.sml
+++ b/fcore/core-key.sml
@@ -135,6 +135,8 @@ sig
     , jump: key_code
     , attack: key_code
     }
+
+  val keyFromString: string -> key_code option
 end
 
 structure CoreKey :> CORE_KEY =
@@ -274,4 +276,128 @@ struct
     , jump: key_code
     , attack: key_code
     }
+
+  fun keyFromString str =
+    case str of
+      "KEY_SPACE" => SOME KEY_SPACE
+    | "KEY_APOSTROPHE" => SOME KEY_APOSTROPHE
+    | "KEY_COMMA" => SOME KEY_COMMA
+    | "KEY_MINUS" => SOME KEY_MINUS
+    | "KEY_PERIOD" => SOME KEY_PERIOD
+    | "KEY_SLASH" => SOME KEY_SLASH
+    | "KEY_0" => SOME KEY_0
+    | "KEY_1" => SOME KEY_1
+    | "KEY_2" => SOME KEY_2
+    | "KEY_3" => SOME KEY_3
+    | "KEY_4" => SOME KEY_4
+    | "KEY_5" => SOME KEY_5
+    | "KEY_6" => SOME KEY_6
+    | "KEY_7" => SOME KEY_7
+    | "KEY_8" => SOME KEY_8
+    | "KEY_9" => SOME KEY_9
+    | "KEY_SEMICOLON" => SOME KEY_SEMICOLON
+    | "KEY_EQUAL" => SOME KEY_EQUAL
+    | "KEY_A" => SOME KEY_A
+    | "KEY_B" => SOME KEY_B
+    | "KEY_C" => SOME KEY_C
+    | "KEY_D" => SOME KEY_D
+    | "KEY_E" => SOME KEY_E
+    | "KEY_F" => SOME KEY_F
+    | "KEY_G" => SOME KEY_G
+    | "KEY_H" => SOME KEY_H
+    | "KEY_I" => SOME KEY_I
+    | "KEY_J" => SOME KEY_J
+    | "KEY_K" => SOME KEY_K
+    | "KEY_L" => SOME KEY_L
+    | "KEY_M" => SOME KEY_M
+    | "KEY_N" => SOME KEY_N
+    | "KEY_O" => SOME KEY_O
+    | "KEY_P" => SOME KEY_P
+    | "KEY_Q" => SOME KEY_Q
+    | "KEY_R" => SOME KEY_R
+    | "KEY_S" => SOME KEY_S
+    | "KEY_T" => SOME KEY_T
+    | "KEY_U" => SOME KEY_U
+    | "KEY_V" => SOME KEY_V
+    | "KEY_W" => SOME KEY_W
+    | "KEY_X" => SOME KEY_X
+    | "KEY_Y" => SOME KEY_Y
+    | "KEY_Z" => SOME KEY_Z
+    | "KEY_LEFT_BRACKET" => SOME KEY_LEFT_BRACKET
+    | "KEY_BACKSLASH" => SOME KEY_BACKSLASH
+    | "KEY_RIGHT_BRACKET" => SOME KEY_RIGHT_BRACKET
+    | "KEY_GRAVE_ACCENT" => SOME KEY_GRAVE_ACCENT
+    | "KEY_WORLD_1" => SOME KEY_WORLD_1
+    | "KEY_WORLD_2" => SOME KEY_WORLD_2
+    | "KEY_ESCAPE" => SOME KEY_ESCAPE
+    | "KEY_ENTER" => SOME KEY_ENTER
+    | "KEY_TAB" => SOME KEY_TAB
+    | "KEY_BACKSPACE" => SOME KEY_BACKSPACE
+    | "KEY_INSERT" => SOME KEY_INSERT
+    | "KEY_DELETE" => SOME KEY_DELETE
+    | "KEY_LEFT" => SOME KEY_LEFT
+    | "KEY_RIGHT" => SOME KEY_RIGHT
+    | "KEY_DOWN" => SOME KEY_DOWN
+    | "KEY_UP" => SOME KEY_UP
+    | "KEY_PAGE_UP" => SOME KEY_PAGE_UP
+    | "KEY_PAGE_DOWN" => SOME KEY_PAGE_DOWN
+    | "KEY_HOME" => SOME KEY_HOME
+    | "KEY_END" => SOME KEY_END
+    | "KEY_CAPS_LOCK" => SOME KEY_CAPS_LOCK
+    | "KEY_SCROLL_LOCK" => SOME KEY_SCROLL_LOCK
+    | "KEY_NUM_LOCK" => SOME KEY_NUM_LOCK
+    | "KEY_PRINT_SCREEN" => SOME KEY_PRINT_SCREEN
+    | "KEY_PAUSE" => SOME KEY_PAUSE
+    | "KEY_F1" => SOME KEY_F1
+    | "KEY_F2" => SOME KEY_F2
+    | "KEY_F3" => SOME KEY_F3
+    | "KEY_F4" => SOME KEY_F4
+    | "KEY_F5" => SOME KEY_F5
+    | "KEY_F6" => SOME KEY_F6
+    | "KEY_F7" => SOME KEY_F7
+    | "KEY_F8" => SOME KEY_F8
+    | "KEY_F9" => SOME KEY_F9
+    | "KEY_F10" => SOME KEY_F10
+    | "KEY_F11" => SOME KEY_F11
+    | "KEY_F12" => SOME KEY_F12
+    | "KEY_F13" => SOME KEY_F13
+    | "KEY_F14" => SOME KEY_F14
+    | "KEY_F15" => SOME KEY_F15
+    | "KEY_F16" => SOME KEY_F16
+    | "KEY_F17" => SOME KEY_F17
+    | "KEY_F18" => SOME KEY_F18
+    | "KEY_F19" => SOME KEY_F19
+    | "KEY_F20" => SOME KEY_F20
+    | "KEY_F21" => SOME KEY_F21
+    | "KEY_F22" => SOME KEY_F22
+    | "KEY_F23" => SOME KEY_F23
+    | "KEY_F24" => SOME KEY_F24
+    | "KEY_F25" => SOME KEY_F25
+    | "KEY_KP_0" => SOME KEY_KP_0
+    | "KEY_KP_1" => SOME KEY_KP_1
+    | "KEY_KP_2" => SOME KEY_KP_2
+    | "KEY_KP_3" => SOME KEY_KP_3
+    | "KEY_KP_4" => SOME KEY_KP_4
+    | "KEY_KP_5" => SOME KEY_KP_5
+    | "KEY_KP_6" => SOME KEY_KP_6
+    | "KEY_KP_7" => SOME KEY_KP_7
+    | "KEY_KP_8" => SOME KEY_KP_8
+    | "KEY_KP_9" => SOME KEY_KP_9
+    | "KEY_KP_DECIMAL" => SOME KEY_KP_DECIMAL
+    | "KEY_KP_DIVIDE" => SOME KEY_KP_DIVIDE
+    | "KEY_KP_MULTIPLY" => SOME KEY_KP_MULTIPLY
+    | "KEY_KP_SUBTRACT" => SOME KEY_KP_SUBTRACT
+    | "KEY_KP_ADD" => SOME KEY_KP_ADD
+    | "KEY_KP_ENTER" => SOME KEY_KP_ENTER
+    | "KEY_KP_EQUAL" => SOME KEY_KP_EQUAL
+    | "KEY_LEFT_SHIFT" => SOME KEY_LEFT_SHIFT
+    | "KEY_LEFT_CONTROL" => SOME KEY_LEFT_CONTROL
+    | "KEY_LEFT_ALT" => SOME KEY_LEFT_ALT
+    | "KEY_LEFT_SUPER" => SOME KEY_LEFT_SUPER
+    | "KEY_RIGHT_SHIFT" => SOME KEY_RIGHT_SHIFT
+    | "KEY_RIGHT_CONTROL" => SOME KEY_RIGHT_CONTROL
+    | "KEY_RIGHT_ALT" => SOME KEY_RIGHT_ALT
+    | "KEY_RIGHT_SUPER" => SOME KEY_RIGHT_SUPER
+    | "KEY_MENU" => SOME KEY_MENU
+    | _ => NONE
 end
diff --git a/oms.mlb b/oms.mlb
index 810912c..6852636 100644
--- a/oms.mlb
+++ b/oms.mlb
@@ -72,4 +72,5 @@ end
 shell/input-state.sml
 shell/gl-shaders.sml
 shell/gl-draw.sml
+shell/parse-controls.sml
 shell/shell.sml
diff --git a/shell/input-state.sml b/shell/input-state.sml
index 8cff41f..5607e65 100644
--- a/shell/input-state.sml
+++ b/shell/input-state.sml
@@ -30,7 +30,9 @@ struct
     , jumpHeld = !(#jumpHeld state)
     }
 
-  fun actionToBool action = action = Input.PRESS
+  (* there are three action states reported by OS: PRESS, REPEAT and RELEASE. 
+   * If input is PRESS or REPEAT, then return true, or else return false. *)
+  fun actionToBool action = action <> Input.RELEASE
 
   fun handleKey (key, action) =
     case GlfwKeyMap.codeFromKey key of
diff --git a/shell/parse-controls.sml b/shell/parse-controls.sml
new file mode 100644
index 0000000..3e5beda
--- /dev/null
+++ b/shell/parse-controls.sml
@@ -0,0 +1 @@
+structure ParseControls = struct end