feat: data frame with lazy relation AltrepDataFrameRelation

R/cpp11.R

@@ -80,6 +80,10 @@ rapi_rel_filter <- function(rel, exprs) {
   .Call(`_duckdb_rapi_rel_filter`, rel, exprs)
 }
 
+rapi_rel_project2 <- function(df, con, exprs) {
+  .Call(`_duckdb_rapi_rel_project2`, df, con, exprs)
+}
+
 rapi_rel_project <- function(rel, exprs) {
   .Call(`_duckdb_rapi_rel_project`, rel, exprs)
 }

R/relational.R

@@ -133,6 +133,19 @@ rel_project <- function(rel, exprs) {
   rethrow_rapi_rel_project(rel, exprs)
 }
 
+#' Lazily project a DuckDB relation object
+#' @param rel the DuckDB relation object
+#' @param exprs a list of DuckDB expressions to project
+#' @return the now projected `duckdb_relation` object
+#' @noRd
+#' @examples
+#' con <- DBI::dbConnect(duckdb())
+#' rel <- rel_from_df(con, mtcars)
+#' rel2 <- rel_project(rel, list(expr_reference("cyl"), expr_reference("disp")))
+rel_project2 <- function(df, con, exprs) {
+  rethrow_rapi_rel_project2(as.data.frame(df), con@conn_ref, exprs)
+}
+
 #' Lazily filter a DuckDB relation object
 #' @param rel the DuckDB relation object
 #' @param exprs a list of DuckDB expressions to filter by

R/rethrow-gen.R

@@ -189,6 +189,15 @@ rethrow_rapi_rel_project <- function(rel, exprs, call = parent.frame(2)) {
   )
 }
 
+rethrow_rapi_rel_project2 <- function(df, con, exprs, call = parent.frame(2)) {
+  rlang::try_fetch(
+    rapi_rel_project2(df, con, exprs),
+    error = function(e) {
+      rethrow_error_from_rapi(e, call)
+    }
+  )
+}
+
 rethrow_rapi_rel_aggregate <- function(rel, groups, aggregates, call = parent.frame(2)) {
   rlang::try_fetch(
     rapi_rel_aggregate(rel, groups, aggregates),
@@ -580,6 +589,7 @@ rethrow_restore <- function() {
   rethrow_rapi_rel_from_df <<- rapi_rel_from_df
   rethrow_rapi_rel_filter <<- rapi_rel_filter
   rethrow_rapi_rel_project <<- rapi_rel_project
+  rethrow_rapi_rel_project2 <<- rapi_rel_project2
   rethrow_rapi_rel_aggregate <<- rapi_rel_aggregate
   rethrow_rapi_rel_order <<- rapi_rel_order
   rethrow_rapi_expr_window <<- rapi_expr_window

src/CMakeLists.txt

@@ -10,6 +10,7 @@ add_library(
   register.cpp
   relational.cpp
   reltoaltrep.cpp
+  altrepdataframe_relation.cpp
   scan.cpp
   statement.cpp
   transform.cpp

src/Makevars

@@ -16,4 +16,4 @@ include Makevars.duckdb
 
 CXX_STD = CXX17
 PKG_CPPFLAGS = -Iinclude -I../inst/include -DDUCKDB_DISABLE_PRINT -DDUCKDB_R_BUILD -DBROTLI_ENCODER_CLEANUP_ON_OOM -Iduckdb/src/include -Iduckdb/third_party/concurrentqueue -Iduckdb/third_party/fast_float -Iduckdb/third_party/fastpforlib -Iduckdb/third_party/fmt/include -Iduckdb/third_party/fsst -Iduckdb/third_party/httplib -Iduckdb/third_party/hyperloglog -Iduckdb/third_party/jaro_winkler -Iduckdb/third_party/jaro_winkler/details -Iduckdb/third_party/libpg_query -Iduckdb/third_party/libpg_query/include -Iduckdb/third_party/lz4 -Iduckdb/third_party/brotli/include -Iduckdb/third_party/brotli/common -Iduckdb/third_party/brotli/dec -Iduckdb/third_party/brotli/enc -Iduckdb/third_party/mbedtls -Iduckdb/third_party/mbedtls/include -Iduckdb/third_party/mbedtls/library -Iduckdb/third_party/miniz -Iduckdb/third_party/pcg -Iduckdb/third_party/re2 -Iduckdb/third_party/skiplist -Iduckdb/third_party/tdigest -Iduckdb/third_party/utf8proc -Iduckdb/third_party/utf8proc/include -Iduckdb/third_party/yyjson/include -Iduckdb/third_party/zstd/include -Iduckdb/extension/parquet/include -Iduckdb/third_party/parquet -Iduckdb/third_party/thrift -Iduckdb/third_party/lz4 -Iduckdb/third_party/brotli/include -Iduckdb/third_party/brotli/common -Iduckdb/third_party/brotli/dec -Iduckdb/third_party/brotli/enc -Iduckdb/third_party/snappy -Iduckdb/third_party/mbedtls -Iduckdb/third_party/mbedtls/include -Iduckdb/third_party/zstd/include -Iduckdb/extension/core_functions/include -I../inst/include -Iduckdb -DDUCKDB_EXTENSION_PARQUET_LINKED -DDUCKDB_BUILD_LIBRARY -DDUCKDB_EXTENSION_CORE_FUNCTIONS_LINKED -DDUCKDB_BUILD_LIBRARY
-OBJECTS=rfuns.o database.o connection.o statement.o register.o relational.o scan.o signal.o transform.o utils.o reltoaltrep.o types.o cpp11.o $(SOURCES)
+OBJECTS=rfuns.o database.o connection.o statement.o register.o relational.o scan.o signal.o transform.o utils.o reltoaltrep.o altrepdataframe_relation.o types.o cpp11.o $(SOURCES)

src/altrepdataframe_relation.cpp

@@ -0,0 +1,22 @@
+#include "altrepdataframe_relation.hpp"
+
+namespace duckdb {
+
+AltrepDataFrameRelation::AltrepDataFrameRelation(shared_ptr<Relation> parent)
+// TODO: which RelationType should be used?
+	: Relation(parent->context, RelationType::AGGREGATE_RELATION), parent(std::move(parent)) {
+}
+
+const vector<ColumnDefinition> &AltrepDataFrameRelation::Columns() {
+	return parent->Columns();
+}
+
+string AltrepDataFrameRelation::ToString(idx_t depth) {
+	return parent->ToString(depth);
+}
+
+bool AltrepDataFrameRelation::IsReadOnly() {
+	return parent->IsReadOnly();
+}
+
+}

src/cpp11.cpp

@@ -154,6 +154,13 @@ extern "C" SEXP _duckdb_rapi_rel_filter(SEXP rel, SEXP exprs) {
   END_CPP11
 }
 // relational.cpp
+SEXP rapi_rel_project2(data_frame df, duckdb::conn_eptr_t con, list exprs);
+extern "C" SEXP _duckdb_rapi_rel_project2(SEXP df, SEXP con, SEXP exprs) {
+  BEGIN_CPP11
+    return cpp11::as_sexp(rapi_rel_project2(cpp11::as_cpp<cpp11::decay_t<data_frame>>(df), cpp11::as_cpp<cpp11::decay_t<duckdb::conn_eptr_t>>(con), cpp11::as_cpp<cpp11::decay_t<list>>(exprs)));
+  END_CPP11
+}
+// relational.cpp
 SEXP rapi_rel_project(duckdb::rel_extptr_t rel, list exprs);
 extern "C" SEXP _duckdb_rapi_rel_project(SEXP rel, SEXP exprs) {
   BEGIN_CPP11
@@ -499,6 +506,7 @@ static const R_CallMethodDef CallEntries[] = {
     {"_duckdb_rapi_rel_names",               (DL_FUNC) &_duckdb_rapi_rel_names,               1},
     {"_duckdb_rapi_rel_order",               (DL_FUNC) &_duckdb_rapi_rel_order,               3},
     {"_duckdb_rapi_rel_project",             (DL_FUNC) &_duckdb_rapi_rel_project,             2},
+    {"_duckdb_rapi_rel_project2",            (DL_FUNC) &_duckdb_rapi_rel_project2,            3},
     {"_duckdb_rapi_rel_set_alias",           (DL_FUNC) &_duckdb_rapi_rel_set_alias,           2},
     {"_duckdb_rapi_rel_set_diff",            (DL_FUNC) &_duckdb_rapi_rel_set_diff,            2},
     {"_duckdb_rapi_rel_set_intersect",       (DL_FUNC) &_duckdb_rapi_rel_set_intersect,       2},

src/include/altrepdataframe_relation.hpp

@@ -0,0 +1,17 @@
+#include "duckdb/main/relation.hpp"
+
+namespace duckdb {
+
+class AltrepDataFrameRelation final : public Relation {
+public:
+	AltrepDataFrameRelation(shared_ptr<Relation> parent);
+
+	shared_ptr<Relation> parent;
+public:
+	const vector<ColumnDefinition> &Columns() override;
+	string ToString(idx_t depth) override;
+	bool IsReadOnly() override;
+};
+
+}
+

src/relational.cpp

@@ -162,6 +162,29 @@ using namespace cpp11;
 	return make_external_prot<RelationWrapper>("duckdb_relation", prot, res);
 }
 
+[[cpp11::register]] SEXP rapi_rel_project2(data_frame df, duckdb::conn_eptr_t con, list exprs) {
+	if (exprs.size() == 0) {
+		warning("rel_project without projection expressions has no effect");
+		return df;
+	}
+	vector<duckdb::unique_ptr<ParsedExpression>> projections;
+	vector<string> aliases;
+
+	for (expr_extptr_t expr : exprs) {
+		auto dexpr = expr->Copy();
+		aliases.push_back(dexpr->GetName());
+		projections.push_back(std::move(dexpr));
+	}
+
+	duckdb::rel_extptr_t rel = cpp11::as_cpp<cpp11::decay_t<duckdb::rel_extptr_t>>(rapi_rel_from_df(con, df, false));
+
+	auto res = make_shared_ptr<ProjectionRelation>(rel->rel, std::move(projections), std::move(aliases));
+
+	cpp11::writable::list prot = {rel};
+
+	return make_external_prot<RelationWrapper>("duckdb_relation", prot, res);
+}
+
 [[cpp11::register]] SEXP rapi_rel_project(duckdb::rel_extptr_t rel, list exprs) {
 	if (exprs.size() == 0) {
 		warning("rel_project without projection expressions has no effect");