feat: implemented the % motion! tested as well

FEATURES.md

@@ -57,7 +57,7 @@
 - [ ] `#` - Search word under cursor backward
 
 ### Other Movement
-- [ ] `%` - Jump to matching bracket
+- [x] `%` - Jump to matching bracket
 - [ ] `{` - Jump to previous paragraph
 - [ ] `}` - Jump to next paragraph
 - [ ] `(` - Jump to previous sentence

internal/editor/integration_motion_jump_test.go

@@ -725,3 +725,378 @@ func TestMoveToColumnInVisualMode(t *testing.T) {
 		}
 	})
 }
+
+func TestJumpToMatchingDelimiter(t *testing.T) {
+	tests := []struct {
+		name     string
+		lines    []string
+		start    core.Position
+		expected core.Position
+	}{
+		{
+			name:     "opening paren jumps forward to matching paren",
+			lines:    []string{"a(b(c)d)e"},
+			start:    core.Position{Line: 0, Col: 1},
+			expected: core.Position{Line: 0, Col: 7},
+		},
+		{
+			name:     "closing paren jumps backward to matching opening paren",
+			lines:    []string{"a(b(c)d)e"},
+			start:    core.Position{Line: 0, Col: 7},
+			expected: core.Position{Line: 0, Col: 1},
+		},
+		{
+			name:     "opening square bracket jumps forward with nesting",
+			lines:    []string{"x[ab[c]d]y"},
+			start:    core.Position{Line: 0, Col: 1},
+			expected: core.Position{Line: 0, Col: 8},
+		},
+		{
+			name:     "closing square bracket jumps backward with nesting",
+			lines:    []string{"x[ab[c]d]y"},
+			start:    core.Position{Line: 0, Col: 8},
+			expected: core.Position{Line: 0, Col: 1},
+		},
+		{
+			name:     "opening brace jumps forward across lines",
+			lines:    []string{"if (ok) {", "  call()", "}"},
+			start:    core.Position{Line: 0, Col: 8},
+			expected: core.Position{Line: 2, Col: 0},
+		},
+		{
+			name:     "closing brace jumps backward across lines",
+			lines:    []string{"if (ok) {", "  call()", "}"},
+			start:    core.Position{Line: 2, Col: 0},
+			expected: core.Position{Line: 0, Col: 8},
+		},
+		{
+			name:     "searches forward on current line when not on delimiter",
+			lines:    []string{"xx (a(b)c) yy"},
+			start:    core.Position{Line: 0, Col: 0},
+			expected: core.Position{Line: 0, Col: 9},
+		},
+		{
+			name:     "no delimiter at or after cursor does nothing",
+			lines:    []string{"xx (a(b)c) yy"},
+			start:    core.Position{Line: 0, Col: 10},
+			expected: core.Position{Line: 0, Col: 10},
+		},
+		{
+			name:     "unmatched opening delimiter does nothing",
+			lines:    []string{"x (abc"},
+			start:    core.Position{Line: 0, Col: 2},
+			expected: core.Position{Line: 0, Col: 2},
+		},
+		{
+			name:     "unmatched closing delimiter does nothing",
+			lines:    []string{"abc)"},
+			start:    core.Position{Line: 0, Col: 3},
+			expected: core.Position{Line: 0, Col: 3},
+		},
+		{
+			name:     "backward matching across lines handles nested delimiters",
+			lines:    []string{"if (a +", "    (b * c)", ")"},
+			start:    core.Position{Line: 2, Col: 0},
+			expected: core.Position{Line: 0, Col: 3},
+		},
+		{
+			name:     "forward matching across lines handles nested delimiters",
+			lines:    []string{"if (a +", "    (b * c)", ")"},
+			start:    core.Position{Line: 0, Col: 3},
+			expected: core.Position{Line: 2, Col: 0},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tm := newTestModelWithLinesAndCursorPos(t, tt.lines, tt.start)
+			sendKeys(tm, "%")
+
+			m := getFinalModel(t, tm)
+			if m.ActiveWindow().Cursor.Line != tt.expected.Line {
+				t.Errorf("CursorY() = %d, want %d", m.ActiveWindow().Cursor.Line, tt.expected.Line)
+			}
+			if m.ActiveWindow().Cursor.Col != tt.expected.Col {
+				t.Errorf("CursorX() = %d, want %d", m.ActiveWindow().Cursor.Col, tt.expected.Col)
+			}
+		})
+	}
+}
+
+func TestJumpToMatchingDelimiterInVisualMode(t *testing.T) {
+	t.Run("test 'v%' selects to matching delimiter", func(t *testing.T) {
+		lines := []string{"foo(bar)baz"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 0, Col: 3})
+		sendKeys(tm, "v", "%")
+
+		m := getFinalModel(t, tm)
+		if m.Mode() != core.VisualMode {
+			t.Errorf("Mode() = %v, want VisualMode", m.Mode())
+		}
+		if m.ActiveWindow().Anchor.Col != 3 {
+			t.Errorf("AnchorX() = %d, want 3", m.ActiveWindow().Anchor.Col)
+		}
+		if m.ActiveWindow().Cursor.Col != 7 {
+			t.Errorf("CursorX() = %d, want 7", m.ActiveWindow().Cursor.Col)
+		}
+	})
+
+	t.Run("test 'v%' from closing delimiter selects backward", func(t *testing.T) {
+		lines := []string{"foo(bar)baz"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 0, Col: 7})
+		sendKeys(tm, "v", "%")
+
+		m := getFinalModel(t, tm)
+		if m.Mode() != core.VisualMode {
+			t.Errorf("Mode() = %v, want VisualMode", m.Mode())
+		}
+		if m.ActiveWindow().Anchor.Col != 7 {
+			t.Errorf("AnchorX() = %d, want 7", m.ActiveWindow().Anchor.Col)
+		}
+		if m.ActiveWindow().Cursor.Col != 3 {
+			t.Errorf("CursorX() = %d, want 3", m.ActiveWindow().Cursor.Col)
+		}
+	})
+
+	t.Run("test 'v%' searches forward on current line before selecting", func(t *testing.T) {
+		lines := []string{"xx (a(b)c) yy"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 0, Col: 0})
+		sendKeys(tm, "v", "%")
+
+		m := getFinalModel(t, tm)
+		if m.Mode() != core.VisualMode {
+			t.Errorf("Mode() = %v, want VisualMode", m.Mode())
+		}
+		if m.ActiveWindow().Anchor.Col != 0 {
+			t.Errorf("AnchorX() = %d, want 0", m.ActiveWindow().Anchor.Col)
+		}
+		if m.ActiveWindow().Cursor.Col != 9 {
+			t.Errorf("CursorX() = %d, want 9", m.ActiveWindow().Cursor.Col)
+		}
+	})
+
+	t.Run("test 'v%' with no delimiter after cursor keeps selection in place", func(t *testing.T) {
+		lines := []string{"xx (a(b)c) yy"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 0, Col: 10})
+		sendKeys(tm, "v", "%")
+
+		m := getFinalModel(t, tm)
+		if m.Mode() != core.VisualMode {
+			t.Errorf("Mode() = %v, want VisualMode", m.Mode())
+		}
+		if m.ActiveWindow().Anchor.Col != 10 {
+			t.Errorf("AnchorX() = %d, want 10", m.ActiveWindow().Anchor.Col)
+		}
+		if m.ActiveWindow().Cursor.Col != 10 {
+			t.Errorf("CursorX() = %d, want 10", m.ActiveWindow().Cursor.Col)
+		}
+	})
+
+	t.Run("test 'v%' on unmatched opening delimiter keeps selection in place", func(t *testing.T) {
+		lines := []string{"x (abc"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 0, Col: 2})
+		sendKeys(tm, "v", "%")
+
+		m := getFinalModel(t, tm)
+		if m.Mode() != core.VisualMode {
+			t.Errorf("Mode() = %v, want VisualMode", m.Mode())
+		}
+		if m.ActiveWindow().Anchor.Col != 2 {
+			t.Errorf("AnchorX() = %d, want 2", m.ActiveWindow().Anchor.Col)
+		}
+		if m.ActiveWindow().Cursor.Col != 2 {
+			t.Errorf("CursorX() = %d, want 2", m.ActiveWindow().Cursor.Col)
+		}
+	})
+
+	t.Run("test 'v%d' deletes the matched delimiter range", func(t *testing.T) {
+		lines := []string{"foo(bar)baz"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 0, Col: 3})
+		sendKeys(tm, "v", "%", "d")
+
+		m := getFinalModel(t, tm)
+		if m.Mode() != core.NormalMode {
+			t.Errorf("Mode() = %v, want NormalMode", m.Mode())
+		}
+		if m.ActiveBuffer().Lines[0].String() != "foobaz" {
+			t.Errorf("Line(0) = %q, want 'foobaz'", m.ActiveBuffer().Lines[0].String())
+		}
+	})
+
+	t.Run("test 'V%' spans matching lines", func(t *testing.T) {
+		lines := []string{"if (ok) {", "  call()", "}"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 0, Col: 8})
+		sendKeys(tm, "V", "%")
+
+		m := getFinalModel(t, tm)
+		if m.Mode() != core.VisualLineMode {
+			t.Errorf("Mode() = %v, want VisualLineMode", m.Mode())
+		}
+		if m.ActiveWindow().Anchor.Line != 0 {
+			t.Errorf("AnchorY() = %d, want 0", m.ActiveWindow().Anchor.Line)
+		}
+		if m.ActiveWindow().Cursor.Line != 2 {
+			t.Errorf("CursorY() = %d, want 2", m.ActiveWindow().Cursor.Line)
+		}
+	})
+
+	t.Run("test 'V%' from closing delimiter selects backward across lines", func(t *testing.T) {
+		lines := []string{"if (ok) {", "  call()", "}"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 2, Col: 0})
+		sendKeys(tm, "V", "%")
+
+		m := getFinalModel(t, tm)
+		if m.Mode() != core.VisualLineMode {
+			t.Errorf("Mode() = %v, want VisualLineMode", m.Mode())
+		}
+		if m.ActiveWindow().Anchor.Line != 2 {
+			t.Errorf("AnchorY() = %d, want 2", m.ActiveWindow().Anchor.Line)
+		}
+		if m.ActiveWindow().Cursor.Line != 0 {
+			t.Errorf("CursorY() = %d, want 0", m.ActiveWindow().Cursor.Line)
+		}
+	})
+
+	t.Run("test 'V%' with no delimiter after cursor keeps selection in place", func(t *testing.T) {
+		lines := []string{"xx (a(b)c) yy"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 0, Col: 10})
+		sendKeys(tm, "V", "%")
+
+		m := getFinalModel(t, tm)
+		if m.Mode() != core.VisualLineMode {
+			t.Errorf("Mode() = %v, want VisualLineMode", m.Mode())
+		}
+		if m.ActiveWindow().Anchor.Line != 0 || m.ActiveWindow().Anchor.Col != 10 {
+			t.Errorf("anchor = (%d,%d), want (0,10)", m.ActiveWindow().Anchor.Line, m.ActiveWindow().Anchor.Col)
+		}
+		if m.ActiveWindow().Cursor.Line != 0 || m.ActiveWindow().Cursor.Col != 10 {
+			t.Errorf("cursor = (%d,%d), want (0,10)", m.ActiveWindow().Cursor.Line, m.ActiveWindow().Cursor.Col)
+		}
+	})
+
+	t.Run("test 'V%' on unmatched opening delimiter keeps selection in place", func(t *testing.T) {
+		lines := []string{"if (abc"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 0, Col: 3})
+		sendKeys(tm, "V", "%")
+
+		m := getFinalModel(t, tm)
+		if m.Mode() != core.VisualLineMode {
+			t.Errorf("Mode() = %v, want VisualLineMode", m.Mode())
+		}
+		if m.ActiveWindow().Anchor.Line != 0 || m.ActiveWindow().Anchor.Col != 3 {
+			t.Errorf("anchor = (%d,%d), want (0,3)", m.ActiveWindow().Anchor.Line, m.ActiveWindow().Anchor.Col)
+		}
+		if m.ActiveWindow().Cursor.Line != 0 || m.ActiveWindow().Cursor.Col != 3 {
+			t.Errorf("cursor = (%d,%d), want (0,3)", m.ActiveWindow().Cursor.Line, m.ActiveWindow().Cursor.Col)
+		}
+	})
+
+	t.Run("test 'V%d' deletes linewise matched range", func(t *testing.T) {
+		lines := []string{"if (ok) {", "  call()", "}"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 0, Col: 8})
+		sendKeys(tm, "V", "%", "d")
+
+		m := getFinalModel(t, tm)
+		if m.Mode() != core.NormalMode {
+			t.Errorf("Mode() = %v, want NormalMode", m.Mode())
+		}
+		if m.ActiveBuffer().LineCount() != 1 {
+			t.Errorf("LineCount() = %d, want 1", m.ActiveBuffer().LineCount())
+		}
+		if m.ActiveBuffer().Lines[0].String() != "" {
+			t.Errorf("Line(0) = %q, want ''", m.ActiveBuffer().Lines[0].String())
+		}
+	})
+
+	t.Run("test 'ctrl+v%' updates block selection to matching delimiter", func(t *testing.T) {
+		lines := []string{"if (ok) {", "  call()", "}"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 0, Col: 8})
+		sendKeys(tm, "ctrl+v", "%")
+
+		m := getFinalModel(t, tm)
+		if m.Mode() != core.VisualBlockMode {
+			t.Errorf("Mode() = %v, want VisualBlockMode", m.Mode())
+		}
+		if m.ActiveWindow().Anchor.Line != 0 || m.ActiveWindow().Anchor.Col != 8 {
+			t.Errorf("anchor = (%d,%d), want (0,8)", m.ActiveWindow().Anchor.Line, m.ActiveWindow().Anchor.Col)
+		}
+		if m.ActiveWindow().Cursor.Line != 2 || m.ActiveWindow().Cursor.Col != 0 {
+			t.Errorf("cursor = (%d,%d), want (2,0)", m.ActiveWindow().Cursor.Line, m.ActiveWindow().Cursor.Col)
+		}
+	})
+
+	t.Run("test 'ctrl+v%' from closing delimiter selects backward", func(t *testing.T) {
+		lines := []string{"if (ok) {", "  call()", "}"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 2, Col: 0})
+		sendKeys(tm, "ctrl+v", "%")
+
+		m := getFinalModel(t, tm)
+		if m.Mode() != core.VisualBlockMode {
+			t.Errorf("Mode() = %v, want VisualBlockMode", m.Mode())
+		}
+		if m.ActiveWindow().Anchor.Line != 2 || m.ActiveWindow().Anchor.Col != 0 {
+			t.Errorf("anchor = (%d,%d), want (2,0)", m.ActiveWindow().Anchor.Line, m.ActiveWindow().Anchor.Col)
+		}
+		if m.ActiveWindow().Cursor.Line != 0 || m.ActiveWindow().Cursor.Col != 8 {
+			t.Errorf("cursor = (%d,%d), want (0,8)", m.ActiveWindow().Cursor.Line, m.ActiveWindow().Cursor.Col)
+		}
+	})
+
+	t.Run("test 'ctrl+v%' with no delimiter after cursor keeps block selection in place", func(t *testing.T) {
+		lines := []string{"xx (a(b)c) yy"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 0, Col: 10})
+		sendKeys(tm, "ctrl+v", "%")
+
+		m := getFinalModel(t, tm)
+		if m.Mode() != core.VisualBlockMode {
+			t.Errorf("Mode() = %v, want VisualBlockMode", m.Mode())
+		}
+		if m.ActiveWindow().Anchor.Line != 0 || m.ActiveWindow().Anchor.Col != 10 {
+			t.Errorf("anchor = (%d,%d), want (0,10)", m.ActiveWindow().Anchor.Line, m.ActiveWindow().Anchor.Col)
+		}
+		if m.ActiveWindow().Cursor.Line != 0 || m.ActiveWindow().Cursor.Col != 10 {
+			t.Errorf("cursor = (%d,%d), want (0,10)", m.ActiveWindow().Cursor.Line, m.ActiveWindow().Cursor.Col)
+		}
+	})
+
+	t.Run("test 'ctrl+v%y' yanks block and exits visual mode", func(t *testing.T) {
+		lines := []string{"if (ok) {", "  call()", "}"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 0, Col: 8})
+		sendKeys(tm, "ctrl+v", "%", "y")
+
+		m := getFinalModel(t, tm)
+		if m.Mode() != core.NormalMode {
+			t.Errorf("Mode() = %v, want NormalMode", m.Mode())
+		}
+	})
+}
+
+func TestJumpToMatchingDelimiterIgnoresCount(t *testing.T) {
+	t.Run("test '5%' in normal mode still performs delimiter matching", func(t *testing.T) {
+		lines := []string{"a(b)c"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 0, Col: 1})
+		sendKeys(tm, "5", "%")
+
+		m := getFinalModel(t, tm)
+		if m.ActiveWindow().Cursor.Col != 3 {
+			t.Errorf("CursorX() = %d, want 3", m.ActiveWindow().Cursor.Col)
+		}
+	})
+
+	t.Run("test 'v5%' in visual mode still performs delimiter matching", func(t *testing.T) {
+		lines := []string{"a(b)c"}
+		tm := newTestModelWithLinesAndCursorPos(t, lines, core.Position{Line: 0, Col: 1})
+		sendKeys(tm, "v", "5", "%")
+
+		m := getFinalModel(t, tm)
+		if m.Mode() != core.VisualMode {
+			t.Errorf("Mode() = %v, want VisualMode", m.Mode())
+		}
+		if m.ActiveWindow().Anchor.Col != 1 {
+			t.Errorf("AnchorX() = %d, want 1", m.ActiveWindow().Anchor.Col)
+		}
+		if m.ActiveWindow().Cursor.Col != 3 {
+			t.Errorf("CursorX() = %d, want 3", m.ActiveWindow().Cursor.Col)
+		}
+	})
+}

internal/input/keymap.go

@@ -50,6 +50,7 @@ func NewNormalKeymap() *Keymap {
 			"ctrl+f": motion.ScrollDownPage{Divisor: 1},
 			";":      action.RepeatFind{Count: 1, Reverse: false},
 			",":      action.RepeatFind{Count: 1, Reverse: true},
+			"%":      motion.JumpToMatchingDelimiter{},
 		},
 		operators: map[string]action.Operator{
 			"d": operator.DeleteOperator{},
@@ -148,6 +149,7 @@ func NewVisualKeymap() *Keymap {
 			"ctrl+f": motion.ScrollDownPage{Divisor: 1},
 			";":      action.RepeatFind{Count: 1, Reverse: false},
 			",":      action.RepeatFind{Count: 1, Reverse: true},
+			"%":      motion.JumpToMatchingDelimiter{},
 			// TODO: O and o. These are fun ones! Should be simple too
 		},
 		operators: map[string]action.Operator{

internal/motion/command_test.go

@@ -315,7 +315,7 @@ func TestCommandHistoryIntegration(t *testing.T) {
 func TestCommandHistoryWithLongHistory(t *testing.T) {
 	t.Run("navigate through 20 commands", func(t *testing.T) {
 		history := make([]string, 20)
-		for i := 0; i < 20; i++ {
+		for i := range 20 {
 			history[i] = string(rune('A' + i))
 		}
 
@@ -329,7 +329,7 @@ func TestCommandHistoryWithLongHistory(t *testing.T) {
 		upAction := MoveCommandHistoryUp{}
 
 		// Navigate to 10th command
-		for i := 0; i < 10; i++ {
+		for range 10 {
 			upAction.Execute(m)
 		}
 
@@ -344,7 +344,7 @@ func TestCommandHistoryWithLongHistory(t *testing.T) {
 
 	t.Run("navigate to very end of long history", func(t *testing.T) {
 		history := make([]string, 50)
-		for i := 0; i < 50; i++ {
+		for i := range 50 {
 			history[i] = string(rune('0' + (i % 10)))
 		}
 
@@ -358,7 +358,7 @@ func TestCommandHistoryWithLongHistory(t *testing.T) {
 		upAction := MoveCommandHistoryUp{}
 
 		// Navigate all the way to the end
-		for i := 0; i < 100; i++ { // Try to go past end
+		for range 100 { // Try to go past end
 			upAction.Execute(m)
 		}
 

internal/motion/delimiter_utils.go

@@ -0,0 +1,113 @@
+package motion
+
+import "git.gophernest.net/azpect/TextEditor/internal/core"
+
+// Delimiter matching helpers operate on byte-indexed columns, which matches the
+// rest of the editor cursor model.
+
+func isDelimiter(ch byte) bool {
+	switch ch {
+	case '{', '}', '[', ']', '(', ')':
+		return true
+	default:
+		return false
+	}
+}
+
+func isOpeningDelimiter(ch byte) bool {
+	return ch == '{' || ch == '[' || ch == '('
+}
+
+func getOppositeDelimiter(ch byte) (byte, bool) {
+	switch ch {
+	case '{':
+		return '}', true
+	case '}':
+		return '{', true
+	case '[':
+		return ']', true
+	case ']':
+		return '[', true
+	case '(':
+		return ')', true
+	case ')':
+		return '(', true
+	default:
+		return 0, false
+	}
+}
+
+func findDelimiterOnLine(line string, startCol int) (int, byte, bool) {
+	if len(line) == 0 {
+		return 0, 0, false
+	}
+
+	col := max(0, startCol)
+	for col < len(line) {
+		ch := line[col]
+		if isDelimiter(ch) {
+			return col, ch, true
+		}
+		col++
+	}
+
+	return 0, 0, false
+}
+
+func findMatchingForward(buf *core.Buffer, line, col int, startDelim, matchDelim byte) (core.Position, bool) {
+	depth := 0
+
+	for y := line; y < buf.LineCount(); y++ {
+		text := buf.Line(y)
+		xStart := 0
+		if y == line {
+			xStart = col + 1
+		}
+
+		for x := xStart; x < len(text); x++ {
+			ch := text[x]
+			if ch == startDelim {
+				depth++
+				continue
+			}
+
+			if ch == matchDelim {
+				if depth == 0 {
+					return core.Position{Line: y, Col: x}, true
+				}
+				depth--
+			}
+		}
+	}
+
+	return core.Position{}, false
+}
+
+func findMatchingBackward(buf *core.Buffer, line, col int, startDelim, matchDelim byte) (core.Position, bool) {
+	depth := 0
+
+	for y := line; y >= 0; y-- {
+		text := buf.Line(y)
+		xStart := len(text) - 1
+		if y == line {
+			xStart = col - 1
+		}
+
+		for x := xStart; x >= 0; x-- {
+			ch := text[x]
+			if ch == startDelim {
+				depth++
+				continue
+			}
+
+			if ch == matchDelim {
+				if depth == 0 {
+					return core.Position{Line: y, Col: x}, true
+				}
+				depth--
+			}
+		}
+	}
+
+	return core.Position{}, false
+}

internal/motion/jump.go

@@ -22,10 +22,7 @@ func visibleLineBounds(win *core.Window, buf *core.Buffer) (int, int) {
 
 	start := win.ScrollY
 	end := start + win.ViewportHeight() - 1
-	end = min(end, buf.LineCount()-1)
+	end = max(min(end, buf.LineCount()-1), start)
-	if end < start {
-		end = start
-	}
 
 	return start, end
 }
@@ -293,3 +290,43 @@ func (a MoveToScreenBottom) Type() core.MotionType { return core.Linewise }
 func (a MoveToScreenBottom) WithCount(n int) action.Action {
 	return MoveToScreenBottom{Count: n}
 }
+
+// Used for the % motion, not countable
+type JumpToMatchingDelimiter struct{}
+
+func (a JumpToMatchingDelimiter) Execute(m action.Model) tea.Cmd {
+	buf := m.ActiveBuffer()
+	if buf.LineCount() == 0 {
+		return nil
+	}
+
+	win := m.ActiveWindow()
+	lineIdx := win.Cursor.Line
+	line := buf.Line(lineIdx)
+
+	col, startDelim, found := findDelimiterOnLine(line, win.Cursor.Col)
+	if !found {
+		return nil
+	}
+
+	matchDelim, ok := getOppositeDelimiter(startDelim)
+	if !ok {
+		return nil
+	}
+
+	var target core.Position
+	if isOpeningDelimiter(startDelim) {
+		target, found = findMatchingForward(buf, lineIdx, col, startDelim, matchDelim)
+	} else {
+		target, found = findMatchingBackward(buf, lineIdx, col, startDelim, matchDelim)
+	}
+
+	if !found {
+		return nil
+	}
+
+	win.SetCursorPos(target.Line, target.Col)
+	return nil
+}
+
+func (a JumpToMatchingDelimiter) Type() core.MotionType { return core.CharwiseInclusive }

internal/textobject/delimiter.go

@@ -194,7 +194,7 @@ func isValidPair(line string, startDelim, endDelim rune, startPos, endPos int) b
 		// A closing quote has an odd number of quotes before it (1, 3, 5, ...)
 
 		quotesBeforeStart := 0
-		for i := 0; i < startPos; i++ {
+		for i := range startPos {
 			if rune(line[i]) == startDelim {
 				quotesBeforeStart++
 			}
@@ -470,7 +470,7 @@ func isCursorBetween(cursor, start, end core.Position) bool {
 
 // hasOnlyWhitespaceBefore checks if there is only whitespace before the character at col.
 func hasOnlyWhitespaceBefore(line string, col int) bool {
-	for i := 0; i < col; i++ {
+	for i := range col {
 		if !isWhitespace(rune(line[i])) {
 			return false
 		}

v0.1.md

@@ -9,7 +9,7 @@
 - [x] Buffer switching
 - [ ] Search (/, ?, n, N) with highlighting
 - [x] Syntax highlighting via treesitter
-- [ ] % (matching bracket)
+- [x] % (matching bracket)
 - [x] J (join lines)
 - [x] H/M/L (screen movement)
 - [ ] Status line (mode, filename, position, modified flag)
@@ -18,7 +18,6 @@
 ## Should Have (Makes it Usable)
 - [ ] :substitute (%s/old/new/g) - at least basic version
 - [ ] Better command-mode autocomplete/hints
-- [ ] Configuration file support (~/.gimrc or similar)
 - [ ] ~Persistent undo history~
 - [ ] ~Line wrapping display option~
 - [x] Horizontal scroll
@@ -40,3 +39,4 @@
 - Macros → v0.2
 - Git integration → v0.3
 - Plugin system → v1.0
+- Configuration file -> v0.3