add readline shortcuts to textbox (ctrl+w, ctrl+u, ctrl+k)

uiterm/textbox.go

@@ -63,9 +63,12 @@ func (t *Textbox) uiDraw() {
 func (t *Textbox) uiKeyEvent(mod Modifier, key Key) {
 	redraw := false
 	switch key {
-	case KeyCtrlC:
+	case KeyCtrlC, KeyCtrlU, KeyCtrlK:
 		t.Text = ""
 		redraw = true
+	case KeyCtrlW:
+		t.Text = deleteWord(t.Text)
+		redraw = true
 	case KeyEnter:
 		if t.Input != nil {
 			t.Input(t.ui, t, t.Text)
@@ -91,6 +94,16 @@ func (t *Textbox) uiKeyEvent(mod Modifier, key Key) {
 	}
 }
 
+func deleteWord(s string) string {
+	// Trim trailing spaces, then trim non-spaces (the word)
+	s = strings.TrimRight(s, " ")
+	i := strings.LastIndex(s, " ")
+	if i < 0 {
+		return ""
+	}
+	return s[:i+1]
+}
+
 func (t *Textbox) uiCharacterEvent(chr rune) {
 	if len(t.Text) >= maxTextboxLen {
 		return