Function IsReserved

internal/keys/parse.go:152–180

IsReserved reports whether the given key combination is reserved for navigation and should not be reassigned. Only unmodified keys are checked.

(key tcell.Key, r rune, mod tcell.ModMask)

// IsReserved reports whether the given key combination is reserved for
// navigation and should not be reassigned. Only unmodified keys are checked.
func IsReserved(key tcell.Key, r rune, mod tcell.ModMask) bool {
	// Unmodified navigation keys cannot be remapped.
	if mod == 0 {
		switch key {
		case tcell.KeyUp, tcell.KeyDown, tcell.KeyLeft, tcell.KeyRight,
			tcell.KeyEsc, tcell.KeyEnter, tcell.KeyBackspace, tcell.KeyBackspace2,
			tcell.KeyTab:
			return true
		case tcell.KeyRune:
			switch unicode.ToLower(r) {
			case 'h', 'j', 'k', 'l':
				return true
			}
		}
	}

	// System-reserved combinations like Ctrl+C should not be reused.
	if key == tcell.KeyRune && (mod&tcell.ModCtrl) != 0 {
		other := mod &^ (tcell.ModCtrl | tcell.ModShift)
		if other == 0 {
			switch unicode.ToLower(r) {
			case 'c', 'd':
				return true
			}
		}
	}

	return false
}

// NormalizeEvent converts an EventKey into a canonical (key,rune,mod) triple.
// Ctrl+A style events are normalized to KeyRune with the corresponding rune.