what is going on

src/database.cpp

@@ -1,4 +1,5 @@
 #include "rapi.hpp"
+#include "r_progress_bar_display.hpp"
 
 #include "duckdb/main/client_context.hpp"
 #include "duckdb/parser/parsed_data/create_table_function_info.hpp"
@@ -16,6 +17,51 @@ static bool CastRstringToVarchar(Vector &source, Vector &result, idx_t count, Ca
 	return true;
 }
 
+unique_ptr<ProgressBarDisplay> RProgressBarDisplay::Create() {
+	return make_uniq<RProgressBarDisplay>();
+}
+
+void RProgressBarDisplay::Initialize() {
+	auto progress_display = Rf_GetOption(RStrings::get().progress_display_sym, R_BaseEnv);
+	if (Rf_isFunction(progress_display)) {
+		progress_callback = progress_display;
+	}
+	D_ASSERT(progress_callback != R_NilValue);
+}
+
+RProgressBarDisplay::RProgressBarDisplay() : ProgressBarDisplay() {
+	// Empty
+}
+
+void RProgressBarDisplay::Update(double percentage) {
+	if (progress_callback == R_NilValue) {
+		Initialize();
+	}
+	if (progress_callback != R_NilValue) {
+	  try {
+	    cpp11::sexp call = Rf_lang2(progress_callback, Rf_ScalarReal(percentage));
+	    cpp11::safe[Rf_eval](call, R_BaseEnv);
+	  } catch (std::exception &e) {
+	    cpp11::stop("RProgressBarDisplay: Failed to update progress bar: %s", e.what());
+	  }
+	}
+}
+
+void RProgressBarDisplay::Finish() {
+	Update(100);
+}
+
+static void SetDefaultConfigArguments(ClientContext &context) {
+  auto progress_display = Rf_GetOption(RStrings::get().progress_display_sym, R_BaseEnv);
+  if (Rf_isFunction(progress_display)) {
+    auto &config = ClientConfig::GetConfig(context);
+    config.enable_progress_bar = true;
+  }
+
+  // Set the function used to create the display for the progress bar
+  context.config.display_create_func = RProgressBarDisplay::Create;
+}
+
 [[cpp11::register]] duckdb::db_eptr_t rapi_startup(std::string dbdir, bool readonly, cpp11::list configsexp, bool environment_scan) {
 	const char *dbdirchar;
 
@@ -76,6 +122,7 @@ static bool CastRstringToVarchar(Vector &source, Vector &result, idx_t count, Ca
 	CreateTableFunctionInfo info(scan_fun);
 	Connection conn(*wrapper->db);
 	auto &context = *conn.context;
+	SetDefaultConfigArguments(context);
 	auto &catalog = Catalog::GetSystemCatalog(context);
 	context.transaction.BeginTransaction();
 

src/include/r_progress_bar_display.hpp

@@ -0,0 +1,28 @@
+#pragma once
+
+#include "rapi.hpp"
+#include "duckdb/common/progress_bar/progress_bar_display.hpp"
+#include "duckdb/common/helper.hpp"
+
+namespace duckdb {
+
+class RProgressBarDisplay : public ProgressBarDisplay {
+public:
+	RProgressBarDisplay();
+	virtual ~RProgressBarDisplay() {
+	}
+
+	static unique_ptr<ProgressBarDisplay> Create();
+
+public:
+	void Update(double percentage) override;
+	void Finish() override;
+
+private:
+	void Initialize();
+
+private:
+	SEXP progress_callback = R_NilValue;
+};
+
+} // namespace duckdb

src/include/rapi.hpp

@@ -171,6 +171,7 @@ struct RStrings {
 	SEXP ImportRecordBatchReader_sym;
 	SEXP materialize_callback_sym;
 	SEXP materialize_message_sym;
+	SEXP progress_display_sym;
 	SEXP duckdb_row_names_sym;
 	SEXP duckdb_vector_sym;
 

src/utils.cpp

@@ -82,6 +82,7 @@ RStrings::RStrings() {
 	Table__from_record_batches_sym = Rf_install("Table__from_record_batches");
 	materialize_message_sym = Rf_install("duckdb.materialize_message");
 	materialize_callback_sym = Rf_install("duckdb.materialize_callback");
+	progress_display_sym = Rf_install("duckdb.progress_display");
 	duckdb_row_names_sym = Rf_install("duckdb_row_names");
 	duckdb_vector_sym = Rf_install("duckdb_vector");
 }