feat: YAML-driven torch op codegen with canonical naming and exposed semantic params

CMakeLists.txt

@@ -92,31 +92,71 @@ endif()
 if(AUTO_DETECT_BACKENDS)
     message(STATUS "Auto-detecting available backends...")
 
+    # The Python that scikit-build's build-isolated environment hands
+    # us does not have `torch` (only `[build-system].requires` is
+    # installed).  Fall back to a list of common system interpreters so
+    # the auto-detection finds `torch` when it is in the install env
+    # but not the build env.  The first interpreter that successfully
+    # imports `torch` wins and is reused by the `WITH_TORCH` block
+    # below for include / library lookups.
     find_package(Python COMPONENTS Interpreter QUIET)
 
-    if(Python_FOUND)
+    set(_torch_python_candidates "${Python_EXECUTABLE}")
+    foreach(_candidate
+            python3
+            python
+            /usr/bin/python3
+            /usr/local/bin/python3
+            /opt/conda/bin/python
+            /opt/conda/bin/python3)
+        find_program(_resolved_${_candidate} ${_candidate})
+        if(_resolved_${_candidate} AND
+           NOT _resolved_${_candidate} STREQUAL "${Python_EXECUTABLE}")
+            list(APPEND _torch_python_candidates "${_resolved_${_candidate}}")
+        endif()
+    endforeach()
+
+    foreach(_py ${_torch_python_candidates})
+        if(NOT _py)
+            continue()
+        endif()
+
         execute_process(
-            COMMAND ${Python_EXECUTABLE} -c "import torch"
+            COMMAND "${_py}" -c "import torch"
             RESULT_VARIABLE _torch_import_result
             OUTPUT_QUIET
             ERROR_QUIET
         )
 
         if(_torch_import_result EQUAL 0)
-            set(WITH_TORCH ON)
-            message(STATUS "Auto-detected PyTorch.")
+            set(_TORCH_PYTHON "${_py}")
+            break()
         endif()
+    endforeach()
+
+    if(_TORCH_PYTHON)
+        set(WITH_TORCH ON)
+        message(STATUS "Auto-detected PyTorch (via ${_TORCH_PYTHON}).")
     endif()
 endif()
 
 if(WITH_TORCH)
     find_package(Python COMPONENTS Interpreter REQUIRED)
 
+    # Prefer the interpreter that the auto-detect block already
+    # confirmed has `torch` (this is the system Python on hosts that
+    # use scikit-build's build-isolation, where the build interpreter
+    # does not have `torch`).  Fall back to `Python_EXECUTABLE` for
+    # explicit `-DWITH_TORCH=ON` invocations.
+    if(NOT _TORCH_PYTHON)
+        set(_TORCH_PYTHON "${Python_EXECUTABLE}")
+    endif()
+
     # Query `torch` paths directly instead of using `find_package(Torch)`,
     # which pulls in Caffe2's CMake config and may fail on platforms with
     # non-standard CUDA toolchains.
     execute_process(
-        COMMAND ${Python_EXECUTABLE} -c "from torch.utils.cpp_extension import include_paths; print(';'.join(include_paths()))"
+        COMMAND ${_TORCH_PYTHON} -c "from torch.utils.cpp_extension import include_paths; print(';'.join(include_paths()))"
         OUTPUT_VARIABLE TORCH_INCLUDE_DIRS
         OUTPUT_STRIP_TRAILING_WHITESPACE
         RESULT_VARIABLE _torch_result
@@ -127,7 +167,7 @@ if(WITH_TORCH)
     endif()
 
     execute_process(
-        COMMAND ${Python_EXECUTABLE} -c "from torch.utils.cpp_extension import library_paths; print(';'.join(library_paths()))"
+        COMMAND ${_TORCH_PYTHON} -c "from torch.utils.cpp_extension import library_paths; print(';'.join(library_paths()))"
         OUTPUT_VARIABLE _torch_lib_dirs
         OUTPUT_STRIP_TRAILING_WHITESPACE
     )
@@ -144,7 +184,7 @@ if(WITH_TORCH)
     # the bundled `NEEDED` entries (otherwise: `undefined reference to
     # _gfortran_etime@GFORTRAN_8` etc.).
     execute_process(
-        COMMAND ${Python_EXECUTABLE} -c "import os, torch; d = os.path.dirname(torch.__file__); p = os.path.join(os.path.dirname(d), 'torch.libs'); print(p if os.path.isdir(p) else '')"
+        COMMAND ${_TORCH_PYTHON} -c "import os, torch; d = os.path.dirname(torch.__file__); p = os.path.join(os.path.dirname(d), 'torch.libs'); print(p if os.path.isdir(p) else '')"
         OUTPUT_VARIABLE TORCH_BUNDLED_LIBS_DIR
         OUTPUT_STRIP_TRAILING_WHITESPACE
     )
@@ -163,7 +203,7 @@ if(WITH_TORCH)
     # A mismatch causes linker errors (e.g. undefined reference to
     # `c10::Device::Device(std::string const&)`).
     execute_process(
-        COMMAND ${Python_EXECUTABLE} -c "import torch; print(int(torch.compiled_with_cxx11_abi()))"
+        COMMAND ${_TORCH_PYTHON} -c "import torch; print(int(torch.compiled_with_cxx11_abi()))"
         OUTPUT_VARIABLE TORCH_CXX11_ABI
         OUTPUT_STRIP_TRAILING_WHITESPACE
         RESULT_VARIABLE _torch_abi_result

pyproject.toml

@@ -1,5 +1,5 @@
 [build-system]
-requires = ["scikit-build-core", "pybind11", "libclang"]
+requires = ["scikit-build-core", "pybind11", "libclang", "pyyaml", "clang-format"]
 build-backend = "scikit_build_core.build"
 
 [project]