implement key and modifier alias

README.md

@@ -168,6 +168,25 @@ command  = command is executed through '$SHELL -c' and
            an EOL character signifies the end of the bind.
 ```
 
+Aliases can also be used anywhere a modifier or a key is expected:
+```
+# alias as modifier
+.alias $hyper cmd + alt + ctrl
+$hyper - t : open -a Terminal.app
+
+# alias as key
+.alias $capslock 0x39
+ctrl - $capslock : open -a Notes.app
+
+# alias as mod-key
+.alias $exclamation_mark shift - 1
+$hyper - $exclamation_mark : open -a "System Preferences.app"
+
+# alias within alias
+.alias $terminal_key $hyper + shift - t
+$terminal_key : open -a Terminal.app
+```
+
 General options that configure the behaviour of **skhd**:
 ```
 # specify a file that should be included as an additional config-file.

examples/skhdrc

@@ -113,3 +113,22 @@ cmd + shift - return : ~/Scripts/qtb.sh
 
 # open mpv
 cmd - m : open -na /Applications/mpv.app $(pbpaste)
+
+###################
+#  using aliases
+
+# alias as modifier
+.alias $hyper cmd + alt + ctrl
+$hyper - t : open -a Terminal.app
+
+# alias as key
+.alias $capslock 0x39
+ctrl - $capslock : open -a Notes.app
+
+# alias as mod-key
+.alias $exclamation_mark shift - 1
+$hyper - $exclamation_mark : open -a "System Preferences.app"
+
+# alias within alias
+.alias $terminal_key $hyper + shift - t
+$terminal_key : open -a Terminal.app

src/hashtable.h

@@ -88,11 +88,11 @@ void *table_find(struct table *table, void *key)
     return bucket ? bucket->value : NULL;
 }
 
-void table_add(struct table *table, void *key, void *value)
+void table_newkeyvalue(struct table *table, void *key, void *value, bool do_replace)
 {
     struct bucket **bucket = table_get_bucket(table, key);
     if (*bucket) {
-        if (!(*bucket)->value) {
+        if (do_replace || !(*bucket)->value) {
             (*bucket)->value = value;
         }
     } else {
@@ -101,6 +101,16 @@ void table_add(struct table *table, void *key, void *value)
     }
 }
 
+void table_add(struct table *table, void *key, void *value)
+{
+    table_newkeyvalue(table, key, value, false);
+}
+
+void table_replace(struct table *table, void *key, void *value)
+{
+    table_newkeyvalue(table, key, value, true);
+}
+
 void *table_remove(struct table *table, void *key)
 {
     void *result = NULL;

src/hotkey.c

@@ -219,20 +219,30 @@ next:;
         free(mode);
     }
 
-    if (mode_count) {
-        free(modes);
-        buf_free(freed_pointers);
-    }
+    free(modes);
+    buf_free(freed_pointers);
 }
 
 void free_blacklist(struct table *blacklst)
 {
     int count;
     void **items = table_reset(blacklst, &count);
     for (int index = 0; index < count; ++index) {
-        char *item = (char *) items[index];
-        free(item);
+        free(items[index]);
     }
+
+    free(items);
+}
+
+void free_alias_map(struct table *alias_map)
+{
+    int count;
+    void **items = table_reset(alias_map, &count);
+    for (int index = 0; index < count; ++index) {
+        free(items[index]);
+    }
+
+    free(items);
 }
 
 static void

src/hotkey.h

@@ -43,6 +43,7 @@ enum hotkey_flag
     Hotkey_Flag_LControl    = (1 << 10),
     Hotkey_Flag_RControl    = (1 << 11),
     Hotkey_Flag_Fn          = (1 << 12),
+    Hotkey_Flag_Modifier    = ((Hotkey_Flag_Fn << 1) - 1),
     Hotkey_Flag_Passthrough = (1 << 13),
     Hotkey_Flag_Activate    = (1 << 14),
     Hotkey_Flag_NX          = (1 << 15),
@@ -109,6 +110,7 @@ bool intercept_systemkey(CGEventRef event, struct hotkey *eventkey);
 bool find_and_exec_hotkey(struct hotkey *k, struct table *t, struct mode **m, struct carbon_event *carbon);
 void free_mode_map(struct table *mode_map);
 void free_blacklist(struct table *blacklst);
+void free_alias_map(struct table *alias_map);
 
 void init_shell(void);