update: enhance `PyCases` interfaces

src/core_ffi/CMakeLists.txt

@@ -18,6 +18,7 @@ if (KLSK_PYTHON_FFI)
         py_ffi/wrapper/cases.cc
         py_ffi/wrapper/py_group_union.cc
         py_ffi/wrapper/py_group.cc
+        py_ffi/binder/cases.cc
     )
     target_include_directories(klotski_py PRIVATE py_ffi/include)
     target_include_directories(klotski_py PRIVATE py_ffi)

src/core_ffi/py_ffi/binder.cc

@@ -24,6 +24,8 @@ using klotski::ffi::PyExc_CodecError;
 using klotski::ffi::PyGroup;
 using klotski::ffi::PyGroupUnion;
 
+extern void bind_cases(const py::module_ &m);
+
 void bind_common_code(const py::module_ &m) {
     py::class_<PyCommonCode>(m, "CommonCode")
         .def(py::init<uint64_t>())
@@ -100,22 +102,11 @@ PYBIND11_MODULE(klotski, m) {
     m.def("all_cases", &all_cases);
     m.def("group_demo", &group_demo);
 
-    auto py_cases = py::class_<PyCases>(m, "Cases")
-        .def("size", &PyCases::size)
-        .def("__iter__", &PyCases::common_codes, py::keep_alive<0, 1>())
-        .def("short_codes", &PyCases::short_codes, py::keep_alive<0, 1>());
-
-    py::class_<PyCases::ShortCodeIter>(py_cases, "ShortCodeIter")
-            .def("__iter__", [](PyCases::ShortCodeIter &it) -> PyCases::ShortCodeIter& { return it; })
-            .def("__next__", &PyCases::ShortCodeIter::next);
-
-    py::class_<PyCases::CommonCodeIter>(py_cases, "CommonCodeIter")
-            .def("__iter__", [](PyCases::CommonCodeIter &it) -> PyCases::CommonCodeIter& { return it; })
-            .def("__next__", &PyCases::CommonCodeIter::next);
-
     bind_short_code(m);
     bind_common_code(m);
 
+    bind_cases(m);
+
     py::class_<PyGroupUnion>(m, "GroupUnion")
         .def(py::init<uint8_t>())
         .def(py::init<PyShortCode>())

src/core_ffi/py_ffi/binder/cases.cc

@@ -0,0 +1,21 @@
+#include <pybind11/pybind11.h>
+#include <pybind11/operators.h>
+
+#include "include/py_cases.h"
+
+namespace py = pybind11;
+
+using klotski::ffi::PyCases;
+using klotski::ffi::PyCasesIter;
+
+void bind_cases(const py::module_ &m) {
+    py::class_<PyCases>(m, "Cases")
+        .def(py::self == py::self)
+        .def("__len__", &PyCases::size)
+        .def("__repr__", &PyCases::repr)
+        .def("__getitem__", &PyCases::at)
+        .def("__iter__", &PyCases::codes, py::keep_alive<0, 1>());
+
+    py::class_<PyCasesIter>(m, "CasesIter")
+        .def("__next__", &PyCasesIter::next);
+}

src/core_ffi/py_ffi/include/py_cases.h

@@ -11,35 +11,27 @@ namespace klotski::ffi {
 
 using cases::RangesUnion;
 
-class PyCases {
+class PyCasesIter {
 public:
-    PyCases() = delete;
-
-    // ------------------------------------------------------------------------------------- //
+    /// Construct from RangesUnion reference.
+    explicit PyCasesIter(const RangesUnion &data);
 
-    class CommonCodeIter {
-    public:
-        PyCommonCode next();
-        explicit CommonCodeIter(const RangesUnion &data);
+    /// Get the next CommonCode or throw a stop_iteration exception.
+    PyCommonCode next();
 
-    private:
-        uint8_t head_ {0};
-        uint32_t index_ {0};
-        const RangesUnion &data_;
-    };
-
-    class ShortCodeIter {
-    public:
-        PyShortCode next();
-        explicit ShortCodeIter(CommonCodeIter iter);
+private:
+    uint8_t head_ {0};
+    uint32_t index_ {0};
+    const RangesUnion &data_;
+};
 
-    private:
-        CommonCodeIter iter_;
-    };
+class PyCases {
+public:
+    PyCases() = delete;
 
     // ------------------------------------------------------------------------------------- //
 
-    /// Constructing from rvalue.
+    /// Constructing from r-value.
     static PyCases from(RangesUnion &&data) noexcept;
 
     /// Constructing from longer-lived reference.
@@ -48,20 +40,23 @@ public:
     // ------------------------------------------------------------------------------------- //
 
     /// Get the number of cases.
-    [[nodiscard]] size_t size() const;
-
-    /// Get ShortCode iterator of cases.
-    [[nodiscard]] ShortCodeIter short_codes() const;
+    [[nodiscard]] size_t size() const noexcept;
 
     /// Get CommonCode iterator of cases.
-    [[nodiscard]] CommonCodeIter common_codes() const;
+    [[nodiscard]] PyCasesIter codes() const noexcept;
 
     /// Get the CommonCode of the specified index.
-    [[nodiscard]] PyCommonCode operator[](size_t index) const;
+    [[nodiscard]] PyCommonCode at(size_t index) const; // TODO: allow `-1` index
 
     // ------------------------------------------------------------------------------------- //
 
-    // TODO: add len / repr
+    /// Wrapper of `__repr__` method in Python.
+    static std::string repr(const PyCases &cases) noexcept;
+
+    /// Compare the cases contents of two PyCases.
+    friend constexpr auto operator==(const PyCases &lhs, const PyCases &rhs);
+
+    // ------------------------------------------------------------------------------------- //
 
 private:
     explicit PyCases(RangesUnion &&data);
@@ -78,6 +73,8 @@ private:
     // ------------------------------------------------------------------------------------- //
 };
 
-// TODO: allow compare
+constexpr auto operator==(const PyCases &lhs, const PyCases &rhs) {
+    return lhs.data_ref() == rhs.data_ref();
+}
 
 } // namespace klotski::ffi

src/core_ffi/py_ffi/wrapper/cases.cc

@@ -1,3 +1,4 @@
+#include <format>
 #include <pybind11/pybind11.h>
 
 #include "include/py_cases.h"
@@ -6,35 +7,25 @@ namespace py = pybind11;
 
 using namespace klotski::ffi;
 
-using ShortCodeIter = PyCases::ShortCodeIter;
-using CommonCodeIter = PyCases::CommonCodeIter;
-
 // ----------------------------------------------------------------------------------------- //
 
-CommonCodeIter::CommonCodeIter(const RangesUnion &data) : data_(data) {}
-
-ShortCodeIter::ShortCodeIter(PyCases::CommonCodeIter iter) : iter_(iter) {}
+PyCasesIter::PyCasesIter(const RangesUnion &data) : data_(data) {}
 
-PyShortCode ShortCodeIter::next() {
-    return iter_.next().short_code();
-}
-
-PyCommonCode CommonCodeIter::next() {
+PyCommonCode PyCasesIter::next() {
     while (head_ < 16) {
         const auto &ranges = data_[head_];
         if (index_ < ranges.size()) {
             auto code = (static_cast<uint64_t>(head_) << 32) | ranges[index_++];
             return std::bit_cast<PyCommonCode>(code);
         }
-        ++head_;
-        index_ = 0;
+        index_ = 0, ++head_;
     }
     throw py::stop_iteration();
 }
 
 // ----------------------------------------------------------------------------------------- //
 
-size_t PyCases::size() const {
+size_t PyCases::size() const noexcept {
     size_t num = 0;
     for (const auto &x : data_ref()) { // TODO: fetch from RangesUnion.size()
         num += x.size();
@@ -42,16 +33,11 @@ size_t PyCases::size() const {
     return num;
 }
 
-auto PyCases::short_codes() const -> ShortCodeIter {
-    return ShortCodeIter(common_codes());
+PyCasesIter PyCases::codes() const noexcept {
+    return PyCasesIter(data_ref());
 }
 
-auto PyCases::common_codes() const -> CommonCodeIter {
-    return CommonCodeIter(data_ref());
-}
-
-PyCommonCode PyCases::operator[](size_t index) const {
-
+PyCommonCode PyCases::at(size_t index) const {
     if (index >= size()) {
         throw py::index_error("cases index out of range");
     }
@@ -72,6 +58,10 @@ PyCommonCode PyCases::operator[](size_t index) const {
     return std::bit_cast<PyCommonCode>(code);
 }
 
+std::string PyCases::repr(const PyCases &cases) noexcept {
+    return std::format("<klotski.Cases size={}>", cases.size());
+}
+
 // ----------------------------------------------------------------------------------------- //
 
 PyCases PyCases::from(RangesUnion &&data) noexcept {