adds support for fn as a modifier key (#169)

Author: smithkyle

src/keypress.h

@@ -20,7 +20,8 @@ extern "C"
 		MOD_META = kCGEventFlagMaskCommand,
 		MOD_ALT = kCGEventFlagMaskAlternate,
 		MOD_CONTROL = kCGEventFlagMaskControl,
-		MOD_SHIFT = kCGEventFlagMaskShift
+		MOD_SHIFT = kCGEventFlagMaskShift,
+		MOD_FUNCTION = kCGEventFlagMaskSecondaryFn
 	} MMKeyFlags;
 
 	extern MMKeyFlags flagBuffer;
@@ -32,7 +33,8 @@ extern "C"
 		MOD_META = Mod4Mask,
 		MOD_ALT = Mod1Mask,
 		MOD_CONTROL = ControlMask,
-		MOD_SHIFT = ShiftMask
+		MOD_SHIFT = ShiftMask,
+		MOD_FUNCTION = 0
 	};
 
 	typedef unsigned int MMKeyFlags;
@@ -45,7 +47,8 @@ extern "C"
 		/* MOD_ALT = 0,
 		MOD_CONTROL = 0,
 		MOD_SHIFT = 0, */
-		MOD_META = MOD_WIN
+		MOD_META = MOD_WIN,
+		MOD_FUNCTION = 0
 	};
 
 	typedef unsigned int MMKeyFlags;

src/macos/keypress.c

@@ -67,6 +67,9 @@ void toggleKeyCode(MMKeyCode code, const bool down, MMKeyFlags flags) {
     if (code == K_SHIFT || code == K_RIGHTSHIFT) {
       flags |= MOD_SHIFT;
     }
+    if (code == K_FUNCTION) {
+      flags |= MOD_FUNCTION;
+    }
 
     MMKeyFlags activeKeyFlags;
     if (down) {

src/main.cc

@@ -361,6 +361,8 @@ int CheckKeyFlags(std::string &flagString, MMKeyFlags *flags) {
         *flags = MOD_CONTROL;
     } else if (flagString == "shift" || flagString == "right_shift") {
         *flags = MOD_SHIFT;
+    } else if (flagString == "fn") {
+        *flags = MOD_FUNCTION;
     } else if (flagString == "none") {
         *flags = MOD_NONE;
     } else {