Implement 'del' in insert mode and tests.

internal/editor/integration_insert_test.go

@@ -392,3 +392,67 @@ func TestInsertModeBackspace(t *testing.T) {
 		}
 	})
 }
+
+func TestInsertModeDelete(t *testing.T) {
+	t.Run("test delete deletes character", func(t *testing.T) {
+		lines := []string{"world"}
+		tm := newTestModelWithCursorPosAndLines(t, lines, action.Position{Col: 3, Line: 0})
+		sendKeys(tm, "i", "delete", "esc")
+
+		m := getFinalModel(t, tm)
+		if m.lines[0] != "word" {
+			t.Errorf("lines[0] = %q, want 'word'", m.lines[0])
+		}
+	})
+
+	t.Run("test delete at end of line joins lines", func(t *testing.T) {
+		lines := []string{"hello", "world"}
+		tm := newTestModelWithCursorPosAndLines(t, lines, action.Position{Col: 5, Line: 0})
+		sendKeys(tm, "i", "delete", "esc")
+
+		m := getFinalModel(t, tm)
+		if len(m.lines) != 1 {
+			t.Errorf("len(lines) = %d, want 1", len(m.lines))
+		}
+		if m.lines[0] != "helloworld" {
+			t.Errorf("lines[0] = %q, want 'helloworld'", m.lines[0])
+		}
+	})
+
+	t.Run("test delete at start of empty line joins lines", func(t *testing.T) {
+		lines := []string{"", "world"}
+		tm := newTestModelWithLines(t, lines)
+		sendKeys(tm, "i", "delete", "esc")
+
+		m := getFinalModel(t, tm)
+		if len(m.lines) != 1 {
+			t.Errorf("len(lines) = %d, want 1", len(m.lines))
+		}
+		if m.lines[0] != "world" {
+			t.Errorf("lines[0] = %q, want 'world'", m.lines[0])
+		}
+	})
+
+	t.Run("test delete at end of last line does nothing", func(t *testing.T) {
+		lines := []string{"hello"}
+		tm := newTestModelWithCursorPosAndLines(t, lines, action.Position{Col: 5, Line: 0})
+		sendKeys(tm, "i", "delete", "esc")
+
+		m := getFinalModel(t, tm)
+		if m.lines[0] != "hello" {
+			t.Errorf("lines[0] = %q, want 'hello'", m.lines[0])
+		}
+	})
+
+	t.Run("test multiple delete", func(t *testing.T) {
+		lines := []string{"hello"}
+		tm := newTestModelWithCursorPosAndLines(t, lines, action.Position{Col: 1, Line: 0})
+		sendKeys(tm, "i", "delete", "delete", "delete", "esc")
+
+		m := getFinalModel(t, tm)
+		if m.lines[0] != "ho" {
+			t.Errorf("lines[0] = %q, want 'he'", m.lines[0])
+		}
+	})
+
+}

internal/editor/model.go

@@ -185,6 +185,15 @@ func (m *Model) processInsertKey(key string) {
 			m.SetCursorX(newX)
 		}
 
+	case "delete":
+		if x == len(l) && y < m.LineCount() {
+			nextLine := m.Line(y + 1)
+			m.SetLine(y, l+nextLine)
+			m.DeleteLine(y + 1)
+		} else if x >= 0 {
+			m.SetLine(y, l[:x]+l[x+1:])
+		}
+
 	// Regular character
 	default:
 		if x < len(l) {

internal/input/keymap.go

@@ -19,7 +19,7 @@ func NewNormalKeymap() *Keymap {
 			"h":  motion.MoveLeft{Count: 1},
 			"l":  motion.MoveRight{Count: 1},
 			"G":  motion.MoveToBottom{},
-			"gg": motion.MoveToTop{}, // multi-key example
+			"gg": motion.MoveToTop{},
 			"0":  motion.MoveToLineStart{},
 			"$":  motion.MoveToLineEnd{},
 		},