feature: add key forwarding

README.md

@@ -18,6 +18,7 @@ list of features
 | blacklist applications     | [x]  |
 | use media-keys as hotkey   | [x]  |
 | synthesize a key-press     | [x]  |
+| noremap / key forwarding   | [x]  |
 
 ### Install
 
@@ -96,6 +97,7 @@ mode         = 'name of mode' | <mode> ',' <mode>
 action       = <keysym> '[' <proc_map_lst> ']' | <keysym> '->' '[' <proc_map_lst> ']'
                <keysym> ':' <command>          | <keysym> '->' ':' <command>
                <keysym> ';' <mode>             | <keysym> '->' ';' <mode>
+               <keysym> '|' <keysym>
 
 keysym       = <mod> '-' <key> | <key>
 
@@ -172,3 +174,11 @@ General options that configure the behaviour of **skhd**:
     "google chrome"
 ]
 ```
+
+Key forwarding (noremap like functionality):
+
+```
+# specify source key (left) and target key (right) to synthesize
+cmd - 1 : yabai -m space --focus 1
+ctrl - 1 | cmd - 1 # press `ctrl - 1` will be `cmd - 1`, bypassing `cmd - 1` command above
+```

src/hotkey.c

@@ -163,6 +163,34 @@ find_process_command_mapping(struct hotkey *hotkey, uint32_t *capture, struct ca
     return result;
 }
 
+bool find_and_forward_hotkey(struct hotkey *k, struct mode *m, CGEventRef event)
+{
+    struct hotkey *found = table_find(&m->hotkey_map, k);
+    if (!found || !found->forwarded_hotkey) return false;
+    debug("forwarding hotkey\n");
+    struct hotkey *forwarded = found->forwarded_hotkey;
+
+    int flags = 0;
+    if (has_flags(forwarded, Hotkey_Flag_Alt)) {
+        flags |= kCGEventFlagMaskAlternate;
+    }
+    if (has_flags(forwarded, Hotkey_Flag_Shift)) {
+        flags |= kCGEventFlagMaskShift;
+    }
+    if (has_flags(forwarded, Hotkey_Flag_Cmd)) {
+        flags |= kCGEventFlagMaskCommand;
+    }
+    if (has_flags(forwarded, Hotkey_Flag_Control)) {
+        flags |= kCGEventFlagMaskControl;
+    }
+    if (has_flags(forwarded, Hotkey_Flag_Fn)) {
+        flags |= kCGEventFlagMaskSecondaryFn;
+    }
+    CGEventSetFlags(event, flags);
+    CGEventSetIntegerValueField(event, kCGKeyboardEventKeycode, forwarded->key);
+    return true;
+}
+
 bool find_and_exec_hotkey(struct hotkey *k, struct table *t, struct mode **m, struct carbon_event *carbon)
 {
     uint32_t c = MODE_CAPTURE((int)(*m)->capture);
@@ -212,6 +240,7 @@ void free_mode_map(struct table *mode_map)
             }
             buf_free(hotkey->command);
 
+            if (hotkey->forwarded_hotkey) free(hotkey->forwarded_hotkey);
             free(hotkey);
 next:;
         }

src/hotkey.h

@@ -76,6 +76,7 @@ struct hotkey
     char **command;
     char *wildcard_command;
     struct mode **mode_list;
+    struct hotkey *forwarded_hotkey;
 };
 
 #define internal static

src/parse.c

@@ -317,7 +317,16 @@ parse_hotkey(struct parser *parser)
         hotkey->flags |= Hotkey_Flag_Passthrough;
     }
 
-    if (parser_match(parser, Token_Command)) {
+    if (parser_match(parser, Token_Forward)) {
+        debug("  forward key stroke: {\n");
+        struct hotkey *forwarded = parse_keypress(parser);
+        if (!forwarded) {
+            parser_report_error(parser, parser_peek(parser), "expect keysym\n");
+            goto err;
+        }
+        hotkey->forwarded_hotkey = forwarded;
+        debug("  }\n");
+    } else if (parser_match(parser, Token_Command)) {
         parse_command(parser, hotkey);
     } else if (parser_match(parser, Token_BeginList)) {
         parse_process_command_list(parser, hotkey);

src/skhd.c

@@ -165,8 +165,11 @@ internal EVENT_TAP_CALLBACK(key_handler)
         if (table_find(&blacklst, carbon.process_name)) return event;
         if (!current_mode) return event;
 
-        BEGIN_TIMED_BLOCK("handle_keypress");
         struct hotkey eventkey = create_eventkey(event);
+        if (find_and_forward_hotkey(&eventkey, current_mode, event)) {
+            return event;
+        }
+        BEGIN_TIMED_BLOCK("handle_keypress");
         bool result = find_and_exec_hotkey(&eventkey, &mode_map, &current_mode, &carbon);
         END_TIMED_BLOCK();
 

src/tokenize.c

@@ -219,6 +219,15 @@ get_token(struct tokenizer *tokenizer)
             token.type = Token_Command;
         }
     } break;
+    case '|': {
+        eat_whitespace(tokenizer);
+
+        token.text = tokenizer->at;
+        token.line = tokenizer->line;
+        token.cursor = tokenizer->cursor;
+
+        token.type = Token_Forward;
+    } break;
     default:  {
         if (c == '0' && *tokenizer->at == 'x') {
             advance(tokenizer);

src/tokenize.h

@@ -47,6 +47,7 @@ enum token_type
     Token_Key,
 
     Token_Decl,
+    Token_Forward,
     Token_Comma,
     Token_Insert,
     Token_Plus,