Add bazel statements needed for pybind11 and export common.h

WORKSPACE

@@ -65,3 +65,53 @@ http_archive(
     urls = ["https://github.com/bazelbuild/platforms/archive/refs/tags/0.0.6.zip"],
     strip_prefix = "platforms-0.0.6",
 )
+
+http_archive(
+    name = "rules_python",
+    sha256 = "62ddebb766b4d6ddf1712f753dac5740bea072646f630eb9982caa09ad8a7687",
+    strip_prefix = "rules_python-0.39.0",
+    url = "https://github.com/bazelbuild/rules_python/releases/download/0.39.0/rules_python-0.39.0.tar.gz",
+)
+
+
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+http_archive(
+    name = "rules_proto",
+    sha256 = "14a225870ab4e91869652cfd69ef2028277fc1dc4910d65d353b62d6e0ae21f4",
+    strip_prefix = "rules_proto-7.1.0",
+    url = "https://github.com/bazelbuild/rules_proto/releases/download/7.1.0/rules_proto-7.1.0.tar.gz",
+)
+
+load("@rules_proto//proto:repositories.bzl", "rules_proto_dependencies")
+rules_proto_dependencies()
+
+load("@rules_proto//proto:toolchains.bzl", "rules_proto_toolchains")
+rules_proto_toolchains()
+
+
+load("@rules_python//python:repositories.bzl", "py_repositories", "python_register_toolchains")
+
+py_repositories()
+
+python_register_toolchains(
+    name = "python",
+    ignore_root_user_error = True,
+    python_version = "3.12",
+)
+
+
+http_archive(
+  name = "pybind11_bazel",
+  strip_prefix = "pybind11_bazel-2.13.6",
+  sha256 = "9df284330336958c837fb70dc34c0a6254dac52a5c983b3373a8c2bbb79ac35e",
+  urls = ["https://github.com/pybind/pybind11_bazel/archive/v2.13.6.zip"],
+)
+# We still require the pybind library.
+http_archive(
+  name = "pybind11",
+  build_file = "@pybind11_bazel//:pybind11-BUILD.bazel",
+  strip_prefix = "pybind11-2.13.6",
+  sha256 = "d0a116e91f64a4a2d8fb7590c34242df92258a61ec644b79127951e821b47be6",
+  urls = ["https://github.com/pybind/pybind11/archive/v2.13.6.zip"],
+)

src/BUILD

@@ -13,6 +13,8 @@
 # limitations under the License.
 
 # load("@benchmark//:benchmark.bzl", "cc_benchmark")
+load("@pybind11_bazel//:build_defs.bzl", "pybind_extension")
+load("@rules_python//python:defs.bzl", "py_library")
 
 package(default_visibility = ["//visibility:public"])
 
@@ -63,6 +65,26 @@ cc_library(
     ],
 )
 
+
+pybind_extension(
+    name = "tesseract_decoder",
+    srcs = [
+        "common.pybind.h",
+        "tesseract.pybind.cc",
+    ],
+    deps = [
+        ":libcommon",
+    ],
+)
+
+
+py_library(
+    name="lib_tesseract_decoder",
+    data=[":tesseract_decoder"],
+    imports=["src"],
+)
+
+
 cc_library(
     name = "libutils",
     srcs = ["utils.cc"],
@@ -171,3 +193,4 @@ cc_binary(
         "@nlohmann_json//:json",
     ],
 )
+

src/common.pybind.h

@@ -0,0 +1,38 @@
+#ifndef TESSERACT_COMMON_PY_H
+#define TESSERACT_COMMON_PY_H
+
+#include <vector>
+
+#include <pybind11/pybind11.h>
+#include <pybind11/stl.h>
+#include <pybind11/operators.h>
+
+#include "common.h"
+
+namespace py = pybind11;
+
+void add_common_module(py::module &root)
+{
+    auto m = root.def_submodule("common", "classes commonly used by the decoder");
+
+    // TODO: add as_dem_instruction_targets
+    py::class_<common::Symptom>(m, "Symptom")
+        .def(py::init<std::vector<int>, common::ObservablesMask>(), py::arg("detectors") = std::vector<int>(), py::arg("observables") = 0)
+        .def_readwrite("detectors", &common::Symptom::detectors)
+        .def_readwrite("observables", &common::Symptom::observables)
+        .def("__str__", &common::Symptom::str)
+        .def(py::self == py::self)
+        .def(py::self != py::self);
+
+    // TODO: add constructor with stim::DemInstruction.
+    py::class_<common::Error>(m, "Error")
+        .def_readwrite("likelihood_cost", &common::Error::likelihood_cost)
+        .def_readwrite("probability", &common::Error::probability)
+        .def_readwrite("symptom", &common::Error::symptom)
+        .def("__str__", &common::Error::str)
+        .def(py::init<>())
+        .def(py::init<double, std::vector<int> &, common::ObservablesMask, std::vector<bool> &>())
+        .def(py::init<double, double, std::vector<int> &, common::ObservablesMask, std::vector<bool> &>());
+}
+
+#endif

src/tesseract.pybind.cc

@@ -0,0 +1,9 @@
+#include <pybind11/pybind11.h>
+#include "pybind11/detail/common.h"
+
+#include "common.pybind.h"
+
+PYBIND11_MODULE(tesseract_py, m)
+{
+    add_common_module(m);
+}