paleolimbot commented on code in PR #13397: URL: https://github.com/apache/arrow/pull/13397#discussion_r918201900
########## r/src/compute.cpp: ########## @@ -574,3 +576,171 @@ SEXP compute__CallFunction(std::string func_name, cpp11::list args, cpp11::list std::vector<std::string> compute__GetFunctionNames() { return arrow::compute::GetFunctionRegistry()->GetFunctionNames(); } + +class RScalarUDFKernelState : public arrow::compute::KernelState { + public: + RScalarUDFKernelState(cpp11::sexp exec_func, cpp11::sexp resolver) + : exec_func_(exec_func), resolver_(resolver) {} + + cpp11::function exec_func_; + cpp11::function resolver_; +}; + +arrow::Result<arrow::TypeHolder> ResolveScalarUDFOutputType( + arrow::compute::KernelContext* context, + const std::vector<arrow::TypeHolder>& input_types) { + return SafeCallIntoR<arrow::TypeHolder>( + [&]() -> arrow::TypeHolder { + auto kernel = + reinterpret_cast<const arrow::compute::ScalarKernel*>(context->kernel()); + auto state = std::dynamic_pointer_cast<RScalarUDFKernelState>(kernel->data); + + cpp11::writable::list input_types_sexp(input_types.size()); + for (size_t i = 0; i < input_types.size(); i++) { + input_types_sexp[i] = + cpp11::to_r6<arrow::DataType>(input_types[i].GetSharedPtr()); + } + + cpp11::sexp output_type_sexp = state->resolver_(input_types_sexp); + if (!Rf_inherits(output_type_sexp, "DataType")) { + cpp11::stop("arrow_scalar_function resolver must return a DataType"); + } + + return arrow::TypeHolder( + cpp11::as_cpp<std::shared_ptr<arrow::DataType>>(output_type_sexp)); + }, + "resolve scalar user-defined function output data type"); +} + +arrow::Status CallRScalarUDF(arrow::compute::KernelContext* context, + const arrow::compute::ExecSpan& span, + arrow::compute::ExecResult* result) { + if (result->is_array_span()) { + return arrow::Status::NotImplemented("ArraySpan result from R scalar UDF"); + } + + return SafeCallIntoRVoid( + [&]() { + auto kernel = + reinterpret_cast<const arrow::compute::ScalarKernel*>(context->kernel()); + auto state = std::dynamic_pointer_cast<RScalarUDFKernelState>(kernel->data); + + cpp11::writable::list args_sexp(span.num_values()); + + for (int i = 0; i < span.num_values(); i++) { + const arrow::compute::ExecValue& exec_val = span[i]; + if (exec_val.is_array()) { + std::shared_ptr<arrow::Array> array = exec_val.array.ToArray(); + args_sexp[i] = cpp11::to_r6<arrow::Array>(array); Review Comment: Fixed! -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@arrow.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org