Claude's attempt at wrapping code

CLAUDE.md

@@ -0,0 +1,47 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project
+
+Textual Diff View — a terminal UI widget (`DiffView`) for displaying diffs, built on the Textual framework. Published to PyPI as `textual-diff-view`.
+
+## Commands
+
+```bash
+# Run all tests
+make test
+# or: uv run pytest tests/
+
+# Update visual snapshots
+make update-snapshots
+# or: uv run pytest tests/ --snapshot-update
+
+# Run a single test
+uv run pytest tests/test_diff_view.py::test_name
+
+# Run example app
+uv run python examples/tdiff.py examples/example1.rs examples/example2.rs
+```
+
+## Architecture
+
+The entire widget lives in `src/textual_diff_view/_diff_view.py`. Public API is just `DiffView` and `LoadError`, exported from `__init__.py`.
+
+**Widget hierarchy** (all Textual widgets):
+- `DiffView` (main widget, `VerticalGroup`) — owns the diff state and renders either split or unified layout via `compose_split()` / `compose_unified()`. Uses Textual's `reactive` attributes with `recompose=True` to re-layout on mode change.
+- `DiffScrollContainer` (`HorizontalGroup`) — syncs horizontal scroll between left/right panels in split view.
+- `LineContent` (`Visual`) — renders a single diff line with syntax highlighting and character-level diff marks.
+- `LineAnnotations` — shows line numbers and optional +/- markers.
+- `DiffCode` (`Static`) — container for code lines, supports text selection.
+- `Ellipsis` — collapsed section indicator (⋮).
+
+**Diff computation**: Uses `difflib.SequenceMatcher` for line-level diffs, then character-level diffs on changed lines. Expensive computation is offloaded via `prepare()` (runs in thread pool). Results are lazily cached via properties (`grouped_opcodes`, `highlighted_code_lines`).
+
+**Syntax highlighting**: Uses Textual's `highlight` module, auto-detecting language from file path.
+
+## Testing
+
+- `tests/test_diff_view.py` — unit tests (fill_lists, counting, opcodes, tab expansion, loading, mounting)
+- `tests/test_snapshots.py` — visual regression tests via `pytest-textual-snapshot`
+- CI runs on Linux/Windows/macOS across Python 3.11–3.14

examples/tdiff.py

@@ -12,10 +12,12 @@ class DiffApp(App):
     BINDINGS = [
         ("space", "toggle('split')", "Toggle split"),
         ("a", "toggle('annotations')", "Toggle annotations"),
+        ("w", "toggle('wrap')", "Toggle wrap"),
     ]
 
     split = var(True)
     annotations = var(True)
+    wrap = var(False)
 
     def __init__(self, original: str, modified: str) -> None:
         self.original = original
@@ -32,7 +34,7 @@ async def on_mount(self) -> None:
         except LoadError as error:
             self.notify(str(error), title="Failed to load code", severity="error")
         else:
-            diff_view.data_bind(DiffApp.split, DiffApp.annotations)
+            diff_view.data_bind(DiffApp.split, DiffApp.annotations, DiffApp.wrap)
             await self.query_one("#diff-container").mount(diff_view)