exduckdb

#include "duckdb/function/table/summary.hpp"
#include "duckdb/function/table_function.hpp"
#include "duckdb/function/function_set.hpp"
#include "duckdb/common/file_system.hpp"

// this function makes not that much sense on its own but is a demo for table-parameter table-producing functions

namespace duckdb {

static unique_ptr<FunctionData> SummaryFunctionBind(ClientContext &context, vector<Value> &inputs,
                                                    unordered_map<string, Value> &named_parameters,
                                                    vector<LogicalType> &input_table_types,
                                                    vector<string> &input_table_names,
                                                    vector<LogicalType> &return_types, vector<string> &names) {

	return_types.push_back(LogicalType::VARCHAR);
	names.emplace_back("summary");

	for (idx_t i = 0; i < input_table_types.size(); i++) {
		return_types.push_back(input_table_types[i]);
		names.emplace_back(input_table_names[i]);
	}

	return make_unique<TableFunctionData>();
}

static void SummaryFunction(ClientContext &context, const FunctionData *bind_data_p, FunctionOperatorData *state_p,
                            DataChunk *input, DataChunk &output) {
	D_ASSERT(input);
	output.SetCardinality(input->size());

	for (idx_t row_idx = 0; row_idx < input->size(); row_idx++) {
		string summary_val = "[";

		for (idx_t col_idx = 0; col_idx < input->ColumnCount(); col_idx++) {
			summary_val += input->GetValue(col_idx, row_idx).ToString();
			if (col_idx < input->ColumnCount() - 1) {
				summary_val += ", ";
			}
		}
		summary_val += "]";
		output.SetValue(0, row_idx, Value(summary_val));
	}
	for (idx_t col_idx = 0; col_idx < input->ColumnCount(); col_idx++) {
		output.data[col_idx + 1].Reference(input->data[col_idx]);
	}
}

void SummaryTableFunction::RegisterFunction(BuiltinFunctions &set) {
	TableFunctionSet summary("summary");
	summary.AddFunction(TableFunction({LogicalType::TABLE}, SummaryFunction, SummaryFunctionBind));
	set.AddFunction(summary);
}

} // namespace duckdb