terminal: Add Alt key bindings for terminal (#14556)

CharlesChen0823 and Peter Tripp created

- Makes using emacs-style alt/option/meta key shortcuts work in terminal (e.g. `M-%`)
- Fixes: #14543 

Co-authored-by: Peter Tripp <peter@zed.dev>

Change summary

crates/terminal/src/mappings/keys.rs | 97 ++++++++++++++++++++++++++++++
1 file changed, 97 insertions(+)

Detailed changes

crates/terminal/src/mappings/keys.rs 🔗

@@ -192,6 +192,103 @@ pub fn to_esc_str(keystroke: &Keystroke, mode: &TermMode, alt_is_meta: bool) ->
         ("^", AlacModifiers::Ctrl) => Some("\x1e".to_string()), //30
         ("_", AlacModifiers::Ctrl) => Some("\x1f".to_string()), //31
         ("?", AlacModifiers::Ctrl) => Some("\x7f".to_string()), //127
+        // Mapping of Alt+key; emacs meta key: M-
+        ("a", AlacModifiers::Alt) => Some("\x1ba".to_string()),
+        ("A", AlacModifiers::Alt) => Some("\x1bA".to_string()),
+        ("b", AlacModifiers::Alt) => Some("\x1bb".to_string()),
+        ("B", AlacModifiers::Alt) => Some("\x1bB".to_string()),
+        ("c", AlacModifiers::Alt) => Some("\x1bc".to_string()),
+        ("C", AlacModifiers::Alt) => Some("\x1bC".to_string()),
+        ("d", AlacModifiers::Alt) => Some("\x1bd".to_string()),
+        ("D", AlacModifiers::Alt) => Some("\x1bD".to_string()),
+        ("e", AlacModifiers::Alt) => Some("\x1be".to_string()),
+        ("E", AlacModifiers::Alt) => Some("\x1bE".to_string()),
+        ("f", AlacModifiers::Alt) => Some("\x1bf".to_string()),
+        ("F", AlacModifiers::Alt) => Some("\x1bF".to_string()),
+        ("g", AlacModifiers::Alt) => Some("\x1bg".to_string()),
+        ("G", AlacModifiers::Alt) => Some("\x1bG".to_string()),
+        ("h", AlacModifiers::Alt) => Some("\x1bh".to_string()),
+        ("H", AlacModifiers::Alt) => Some("\x1bH".to_string()),
+        ("i", AlacModifiers::Alt) => Some("\x1bi".to_string()),
+        ("I", AlacModifiers::Alt) => Some("\x1bI".to_string()),
+        ("j", AlacModifiers::Alt) => Some("\x1bj".to_string()),
+        ("J", AlacModifiers::Alt) => Some("\x1bJ".to_string()),
+        ("k", AlacModifiers::Alt) => Some("\x1bk".to_string()),
+        ("K", AlacModifiers::Alt) => Some("\x1bK".to_string()),
+        ("l", AlacModifiers::Alt) => Some("\x1bl".to_string()),
+        ("L", AlacModifiers::Alt) => Some("\x1bL".to_string()),
+        ("m", AlacModifiers::Alt) => Some("\x1bm".to_string()),
+        ("M", AlacModifiers::Alt) => Some("\x1bM".to_string()),
+        ("n", AlacModifiers::Alt) => Some("\x1bn".to_string()),
+        ("N", AlacModifiers::Alt) => Some("\x1bN".to_string()),
+        ("o", AlacModifiers::Alt) => Some("\x1bo".to_string()),
+        ("O", AlacModifiers::Alt) => Some("\x1bO".to_string()),
+        ("p", AlacModifiers::Alt) => Some("\x1bp".to_string()),
+        ("P", AlacModifiers::Alt) => Some("\x1bP".to_string()),
+        ("q", AlacModifiers::Alt) => Some("\x1bq".to_string()),
+        ("Q", AlacModifiers::Alt) => Some("\x1bQ".to_string()),
+        ("r", AlacModifiers::Alt) => Some("\x1br".to_string()),
+        ("R", AlacModifiers::Alt) => Some("\x1bR".to_string()),
+        ("s", AlacModifiers::Alt) => Some("\x1bs".to_string()),
+        ("S", AlacModifiers::Alt) => Some("\x1bS".to_string()),
+        ("t", AlacModifiers::Alt) => Some("\x1bt".to_string()),
+        ("T", AlacModifiers::Alt) => Some("\x1bT".to_string()),
+        ("u", AlacModifiers::Alt) => Some("\x1bu".to_string()),
+        ("U", AlacModifiers::Alt) => Some("\x1bU".to_string()),
+        ("v", AlacModifiers::Alt) => Some("\x1bv".to_string()),
+        ("V", AlacModifiers::Alt) => Some("\x1bV".to_string()),
+        ("w", AlacModifiers::Alt) => Some("\x1bw".to_string()),
+        ("W", AlacModifiers::Alt) => Some("\x1bW".to_string()),
+        ("x", AlacModifiers::Alt) => Some("\x1bx".to_string()),
+        ("X", AlacModifiers::Alt) => Some("\x1bX".to_string()),
+        ("y", AlacModifiers::Alt) => Some("\x1by".to_string()),
+        ("Y", AlacModifiers::Alt) => Some("\x1bY".to_string()),
+        ("z", AlacModifiers::Alt) => Some("\x1bz".to_string()),
+        ("Z", AlacModifiers::Alt) => Some("\x1bZ".to_string()),
+        // Emacs Numeric arguments / prefix arguments
+        ("0", AlacModifiers::Alt) => Some("\x1b0".to_string()),
+        ("1", AlacModifiers::Alt) => Some("\x1b1".to_string()),
+        ("2", AlacModifiers::Alt) => Some("\x1b2".to_string()),
+        ("3", AlacModifiers::Alt) => Some("\x1b3".to_string()),
+        ("4", AlacModifiers::Alt) => Some("\x1b4".to_string()),
+        ("5", AlacModifiers::Alt) => Some("\x1b5".to_string()),
+        ("6", AlacModifiers::Alt) => Some("\x1b6".to_string()),
+        ("7", AlacModifiers::Alt) => Some("\x1b7".to_string()),
+        ("8", AlacModifiers::Alt) => Some("\x1b8".to_string()),
+        ("9", AlacModifiers::Alt) => Some("\x1b9".to_string()),
+        // Various Emacs Meta key combinations
+        ("!", AlacModifiers::Alt) => Some("\x1b!".to_string()),
+        // ("\"", AlacModifiers::Alt) => Some("\x1b\"".to_string()),
+        // ("#", AlacModifiers::Alt) => Some("\x1b#".to_string()),
+        ("$", AlacModifiers::Alt) => Some("\x1b$".to_string()),
+        ("%", AlacModifiers::Alt) => Some("\x1b%".to_string()),
+        ("&", AlacModifiers::Alt) => Some("\x1b&".to_string()),
+        ("'", AlacModifiers::Alt) => Some("\x1b'".to_string()),
+        ("(", AlacModifiers::Alt) => Some("\x1b(".to_string()),
+        (")", AlacModifiers::Alt) => Some("\x1b)".to_string()),
+        // ("*", AlacModifiers::Alt) => Some("\x1b*".to_string()),
+        // ("+", AlacModifiers::Alt) => Some("\x1b+".to_string()),
+        (",", AlacModifiers::Alt) => Some("\x1b,".to_string()),
+        ("-", AlacModifiers::Alt) => Some("\x1b-".to_string()),
+        (".", AlacModifiers::Alt) => Some("\x1b.".to_string()),
+        ("/", AlacModifiers::Alt) => Some("\x1b/".to_string()),
+        (":", AlacModifiers::Alt) => Some("\x1b:".to_string()),
+        (";", AlacModifiers::Alt) => Some("\x1b;".to_string()),
+        ("<", AlacModifiers::Alt) => Some("\x1b<".to_string()),
+        ("=", AlacModifiers::Alt) => Some("\x1b=".to_string()),
+        (">", AlacModifiers::Alt) => Some("\x1b>".to_string()),
+        ("?", AlacModifiers::Alt) => Some("\x1b?".to_string()),
+        ("@", AlacModifiers::Alt) => Some("\x1b@".to_string()),
+        // ("[", AlacModifiers::Alt) => Some("\x1b[".to_string()),
+        ("\\", AlacModifiers::Alt) => Some("\x1b\\".to_string()),
+        // ("]", AlacModifiers::Alt) => Some("\x1b]".to_string()),
+        ("^", AlacModifiers::Alt) => Some("\x1b^".to_string()),
+        // ("_", AlacModifiers::Alt) => Some("\x1b_".to_string()),
+        ("`", AlacModifiers::Alt) => Some("\x1b`".to_string()),
+        ("{", AlacModifiers::Alt) => Some("\x1b{".to_string()),
+        ("|", AlacModifiers::Alt) => Some("\x1b|".to_string()),
+        ("}", AlacModifiers::Alt) => Some("\x1b}".to_string()),
+        ("~", AlacModifiers::Alt) => Some("\x1b~".to_string()),
         _ => None,
     };
     if manual_esc_str.is_some() {