Add pybind11/eigen.h type_caster for pkbind; simplify RDP bindings

CLAUDE.md

@@ -0,0 +1,81 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+**pocket_numpy** (repo: xtensor-numpy) is a C++ project that integrates the pocketpy lightweight Python interpreter with numpy-like array functionality powered by xtensor and Eigen. It produces:
+- A native CLI (`pocketpy.exe`) that runs Python scripts with numpy support
+- Python wheels via pybind11 (package name: `pocket_numpy`)
+- A WebAssembly build for browser deployment
+
+## Build & Test Commands
+
+```bash
+# Build (installs in editable mode with scikit-build-core)
+make build
+
+# Run numpy tests via pocketpy CLI
+make test                              # runs: build/pocketpy.exe tests/test_numpy.py
+
+# Run a single test file
+build/pocketpy.exe tests/test_numpy.py
+
+# Run tests via pytest (after pip install)
+python3 -m pytest tests/
+
+# Install as pip package
+make python_install
+
+# Build WASM
+make build_wasm
+
+# Serve WASM demo locally
+make serve_wasm
+```
+
+## Architecture
+
+### Core Type System (`include/numpy.hpp`)
+
+Defines C++ type aliases (int8–64, uint8–64, float32, float64, bool_, complex64/128) and `dtype_traits<T>` template for runtime dtype identification. Contains the `ndarray<T>` template backed by `xt::xarray<T>`.
+
+### Polymorphic ndarray (`include/ndarray_binding.hpp`)
+
+`ndarray_base` is an abstract base class with ~80+ virtual methods (shape, reductions, slicing, arithmetic, sorting, etc.). `ndarray<T>` is the concrete template implementation. This virtual dispatch pattern enables a single Python-facing interface that works across all numeric types via `std::unique_ptr<ndarray_base>`.
+
+### Module Bindings (`src/numpy.cpp`)
+
+Registers the `numpy` module into pocketpy's runtime. Binds all ndarray methods, array creation functions (ones, zeros, full, arange, linspace, identity), random number generation, and dtype attributes. This is the largest source file.
+
+### RDP Bindings (`src/pybind.cpp` + `src/rdp.hpp`)
+
+Ramer-Douglas-Peucker polyline simplification exposed via pybind11 as the `_core` module. Supports 2D and 3D point arrays using Eigen matrix types.
+
+### CLI Entry Point (`src/main.cpp`)
+
+Initializes pocketpy, registers the numpy module via `py_module_initialize()`, then executes a Python script or enters REPL mode.
+
+### Dependencies
+
+- **pocketpy** — git submodule at `pocketpy/`
+- **xtensor, xtl, Eigen** — vendored headers in `include/`
+- **pybind11** — required via pip/CMake for Python wheel builds
+
+### Build Targets (CMake)
+
+- `numpy` — static library (numpy.cpp + pocketpy)
+- `pocketpy_cli` — CLI executable linked against numpy
+- `_core` — pybind11 module for RDP bindings
+
+## Git Policy
+
+- **NEVER use `git commit --amend`**. Always create a new commit instead. Amending rewrites history and can destroy previous work, especially after a failed pre-commit hook where `--amend` would silently modify the wrong commit.
+
+## Key Conventions
+
+- C++17 required; C11 for pocketpy C sources
+- Default build type is Release with `-O3`; debug uses `-O0 -ggdb`
+- xtensor warnings are suppressed by default (`SHOW_XTENSOR_WARNINGS=OFF`)
+- Tests are standalone Python scripts (not pytest-based) so they can also run under pocketpy and WASM
+- macOS deployment target is 10.14+ (required for `std::visit`)

README.md

@@ -6,6 +6,10 @@ python3 -m pocket_numpy --help
 python3 -m pocket_numpy tests/test_numpy.py
 ```
 
+# Try is online
+
+<https://cubao.github.io/xtensor-numpy>
+
 ---
 
 # How to build (for dev)