From 0f7d8a68dc8036cfc0b64dd3d2bea6203721b253 Mon Sep 17 00:00:00 2001
From: Kruno Tomola Fabro <krunotf@memgraph.io>
Date: Tue, 23 Aug 2016 14:16:54 +0100
Subject: [PATCH 1/3] Tmp commit.
---
include/utils/iterator/filter.hpp | 49 +++++++++++++++++++++++++++++
include/utils/iterator/iterator.hpp | 1 +
include/utils/iterator/query.hpp | 29 +++++++++++++++++
poc/tool.cpp | 3 +-
4 files changed, 81 insertions(+), 1 deletion(-)
create mode 100644 include/utils/iterator/filter.hpp
create mode 100644 include/utils/iterator/query.hpp
diff --git a/include/utils/iterator/filter.hpp b/include/utils/iterator/filter.hpp
new file mode 100644
index 000000000..2a45d23fe
--- /dev/null
+++ b/include/utils/iterator/filter.hpp
@@ -0,0 +1,49 @@
+#pragma once
+
+#include "utils/iterator/iterator_base.hpp"
+#include "utils/option.hpp"
+
+namespace iter
+{
+
+// Class which filters values T returned by I iterator if OP returns true for
+// them.
+// T - type of return value
+// I - iterator type
+// OP - type of filter function
+template <class T, class I, class OP>
+class Filter : public IteratorBase<T>
+{
+
+public:
+ Filter() = delete;
+
+ // Filter operation is designed to be used in chained calls which operate on
+ // a
+ // iterator. Filter will in that usecase receive other iterator by value and
+ // std::move is a optimization for it.
+ Filter(I &&iter, OP &&op) : iter(std::move(iter)), op(std::move(op)) {}
+
+ Option<T> next() final
+ {
+ auto item = iter.next();
+ if (item.is_present() && op(item.get())) {
+ return std::move(item);
+ } else {
+ return Option<T>();
+ }
+ }
+
+private:
+ I iter;
+ OP op;
+};
+
+template <class I, class OP>
+auto make_filter(I &&iter, OP &&op)
+{
+ // Compiler cant deduce type T. decltype is here to help with it.
+ return Filter<decltype(iter.next().take()), I, OP>(std::move(iter),
+ std::move(op));
+}
+}
diff --git a/include/utils/iterator/iterator.hpp b/include/utils/iterator/iterator.hpp
index 93e48a67d..8a42b10ac 100644
--- a/include/utils/iterator/iterator.hpp
+++ b/include/utils/iterator/iterator.hpp
@@ -1,6 +1,7 @@
#pragma once
#include "utils/iterator/accessor.hpp"
+#include "utils/iterator/filter.hpp"
#include "utils/iterator/for_all.hpp"
#include "utils/iterator/iterator_accessor.hpp"
#include "utils/iterator/iterator_base.hpp"
diff --git a/include/utils/iterator/query.hpp b/include/utils/iterator/query.hpp
new file mode 100644
index 000000000..b3fa64365
--- /dev/null
+++ b/include/utils/iterator/query.hpp
@@ -0,0 +1,29 @@
+#pragma once
+
+#include "storage/vertex_accessor.hpp"
+#include "utils/iterator/iterator.hpp"
+#include "utils/option.hpp"
+
+namespace query_help
+{
+
+template <class A>
+bool fill(A &a)
+{
+ return a.fill();
+}
+};
+
+// Base iterator for next() kind iterator.
+// Vertex::Accessor - type of return value
+template <>
+class IteratorBase<Vertex::Accessor>
+{
+public:
+ virtual Option<Vertex::Accessor> next() = 0;
+
+ auto fill()
+ {
+ return iter::make_filter(std::move(*this), query_help::fill);
+ }
+};
diff --git a/poc/tool.cpp b/poc/tool.cpp
index 616db34f2..a60ee9ae7 100644
--- a/poc/tool.cpp
+++ b/poc/tool.cpp
@@ -13,6 +13,7 @@
#include "storage/record_accessor.cpp"
#include "storage/vertex_accessor.cpp"
#include "utils/command_line/arguments.hpp"
+#include "utils/iterator/query.hpp"
using namespace std;
@@ -164,7 +165,7 @@ void oportunity_employe_company(
const EdgeType &type_created, const EdgeType &type_works_in,
const Label &label_company)
{
- iter::for_all_fill(va.in(), [&](auto opp_e) {
+ iter::for_all(va.in().fill(), [&](auto opp_e) {
// cout << " oec.in()" << endl;
from_fill(opp_e, type_created, [&](auto creator) {
// cout << " type_created" << endl;
From 4542b56c188b4ec2218df538497c41e1e08076e8 Mon Sep 17 00:00:00 2001
From: Kruno Tomola Fabro <krunotf@memgraph.io>
Date: Tue, 30 Aug 2016 02:32:31 +0100
Subject: [PATCH 2/3] tmp commit
---
include/barrier/barrier.hpp | 23 +++-
include/barrier/trans.hpp | 8 +-
include/database/db_accessor.hpp | 8 ++
include/query_engine/hardcode/queries.hpp | 134 ++++++++++++++++++----
include/utils/iterator/filter.hpp | 52 +++++++++
include/utils/iterator/for_all.hpp | 13 +++
poc/profile.hpp | 13 ---
src/barrier/barrier.cpp | 15 ++-
8 files changed, 227 insertions(+), 39 deletions(-)
create mode 100644 include/utils/iterator/filter.hpp
diff --git a/include/barrier/barrier.hpp b/include/barrier/barrier.hpp
index e201b9d61..748358c54 100644
--- a/include/barrier/barrier.hpp
+++ b/include/barrier/barrier.hpp
@@ -25,6 +25,7 @@ class EdgeIterator;
// TYPED ITERATORS
class VertexAccessIterator;
+class EdgeAccessIterator;
class OutEdgesIterator;
class InEdgesIterator;
@@ -247,6 +248,8 @@ public:
VertexAccessor vertex_insert();
+ EdgeAccessIterator edge_access();
+
Option<const EdgeAccessor> edge_find(const Id &id);
EdgeAccessor edge_insert(VertexAccessor const &from,
@@ -309,6 +312,22 @@ public:
Option<const VertexAccessor> next();
};
+// TODO: Find reasons of such great size ant try to decrease it.
+class EdgeAccessIterator : private Sized<552, 8>
+{
+public:
+ template <class T>
+ EdgeAccessIterator(T &&d);
+
+ EdgeAccessIterator(const EdgeAccessIterator &other) = delete;
+ EdgeAccessIterator(EdgeAccessIterator &&other);
+ ~EdgeAccessIterator();
+ EdgeAccessIterator &operator=(const EdgeAccessIterator &other) = delete;
+ EdgeAccessIterator &operator=(EdgeAccessIterator &&other) = delete;
+
+ Option<const EdgeAccessor> next();
+};
+
class OutEdgesIterator : private Sized<40, 8>
{
public:
@@ -442,10 +461,10 @@ public:
void write_success_empty();
void write_ignored();
void write_fields(const std::vector<std::string> &fields);
- void write_field(const std::string& field);
+ void write_field(const std::string &field);
void write_list_header(size_t size);
void write_record();
- void write_meta(const std::string& type);
+ void write_meta(const std::string &type);
void send();
void chunk();
};
diff --git a/include/barrier/trans.hpp b/include/barrier/trans.hpp
index af7c8ad76..2aa927d98 100644
--- a/include/barrier/trans.hpp
+++ b/include/barrier/trans.hpp
@@ -5,9 +5,9 @@
// This is the place for imports from memgraph .hpp
#include "communication/bolt/v1/serialization/bolt_serializer.hpp"
#include "communication/bolt/v1/serialization/record_stream.hpp"
-#include "io/network/socket.hpp"
#include "database/db.hpp"
#include "database/db_accessor.hpp"
+#include "io/network/socket.hpp"
#include "storage/edge_type/edge_type.hpp"
#include "storage/edge_x_vertex.hpp"
#include "storage/label/label.hpp"
@@ -126,6 +126,9 @@
using vertex_access_iterator_t =
decltype(((::DbAccessor *)(std::nullptr_t()))->vertex_access());
+using edge_access_iterator_t =
+ decltype(((::DbAccessor *)(std::nullptr_t()))->edge_access());
+
using out_edge_iterator_t =
decltype(((::VertexAccessor *)(std::nullptr_t()))->out());
@@ -160,6 +163,7 @@ TRANSFORM_REF(VertexIterator,
TRANSFORM_REF(EdgeIterator,
std::unique_ptr<IteratorBase<const ::EdgeAccessor>>);
TRANSFORM_REF(VertexAccessIterator, vertex_access_iterator_t);
+TRANSFORM_REF(EdgeAccessIterator, edge_access_iterator_t);
TRANSFORM_REF(OutEdgesIterator, out_edge_iterator_t);
TRANSFORM_REF(InEdgesIterator, in_edge_iterator_t);
@@ -190,6 +194,8 @@ TRANSFORM_VALUE(VertexPropertyKey,
::VertexPropertyFamily::PropertyType::PropertyFamilyKey);
TRANSFORM_VALUE_ONE(VertexAccessIterator, vertex_access_iterator_t);
MOVE_CONSTRUCTOR_FORCED(VertexAccessIterator, vertex_access_iterator_t);
+TRANSFORM_VALUE_ONE(EdgeAccessIterator, edge_access_iterator_t);
+MOVE_CONSTRUCTOR_FORCED(EdgeAccessIterator, edge_access_iterator_t);
TRANSFORM_VALUE_ONE(OutEdgesIterator, out_edge_iterator_t);
MOVE_CONSTRUCTOR_FORCED(OutEdgesIterator, out_edge_iterator_t);
TRANSFORM_VALUE_ONE(InEdgesIterator, in_edge_iterator_t);
diff --git a/include/database/db_accessor.hpp b/include/database/db_accessor.hpp
index 8614a341a..8df93dfb8 100644
--- a/include/database/db_accessor.hpp
+++ b/include/database/db_accessor.hpp
@@ -69,6 +69,14 @@ public:
VertexAccessor vertex_insert();
// ******************* EDGE METHODS
+ auto edge_access()
+ {
+ return iter::make_map(
+ iter::make_iter(this->db_transaction.db.graph.edges.access()),
+ [&](auto e) -> auto {
+ return EdgeAccessor(&(e->second), db_transaction);
+ });
+ }
Option<const EdgeAccessor> edge_find(const Id &id);
diff --git a/include/query_engine/hardcode/queries.hpp b/include/query_engine/hardcode/queries.hpp
index f50d7c0c4..11b7bfa5a 100644
--- a/include/query_engine/hardcode/queries.hpp
+++ b/include/query_engine/hardcode/queries.hpp
@@ -20,8 +20,7 @@ auto load_queries(Db &db)
auto vertex_accessor = t.vertex_insert();
vertex_accessor.set(prop_key, args[0]);
- t.commit();
- return true;
+ return t.commit();
};
queries[11597417457737499503u] = create_node;
@@ -34,8 +33,7 @@ auto load_queries(Db &db)
vertex_accessor.set(prop_key, args[0]);
vertex_accessor.add_label(label);
// cout_properties(vertex_accessor.properties());
- t.commit();
- return true;
+ return t.commit();
};
auto create_account = [&db](const properties_t &args) {
@@ -53,8 +51,7 @@ auto load_queries(Db &db)
vertex_accessor.set(prop_created, args[3]);
vertex_accessor.add_label(label);
// cout_properties(vertex_accessor.properties());
- t.commit();
- return true;
+ return t.commit();
};
auto find_node_by_internal_id = [&db](const properties_t &args) {
@@ -71,8 +68,7 @@ auto load_queries(Db &db)
for (auto label_ref : vertex_accessor.labels()) {
// cout << label_ref.get() << endl;
}
- t.commit();
- return true;
+ return t.commit();
};
auto create_edge = [&db](const properties_t &args) {
@@ -89,13 +85,13 @@ auto load_queries(Db &db)
edge_accessor.edge_type(edge_type);
- t.commit();
+ bool ret = t.commit();
// cout << edge_accessor.edge_type() << endl;
// cout_properties(edge_accessor.properties());
- return true;
+ return ret;
};
auto find_edge_by_internal_id = [&db](const properties_t &args) {
@@ -119,9 +115,7 @@ auto load_queries(Db &db)
cout << "TO:" << endl;
// cout_properties(to->data.props);
- t.commit();
-
- return true;
+ return t.commit();
};
auto update_node = [&db](const properties_t &args) {
@@ -135,9 +129,7 @@ auto load_queries(Db &db)
v.set(prop_name, args[1]);
// cout_properties(v.properties());
- t.commit();
-
- return true;
+ return t.commit();
};
// MATCH (n1), (n2) WHERE ID(n1)=0 AND ID(n2)=1 CREATE (n1)<-[r:IS {age: 25,
@@ -158,8 +150,7 @@ auto load_queries(Db &db)
auto &IS = t.type_find_or_create("IS");
r.edge_type(IS);
- t.commit();
- return true;
+ return t.commit();
};
// MATCH (n) RETURN n
@@ -172,7 +163,7 @@ auto load_queries(Db &db)
}
});
- return t.commit(), true;
+ return t.commit();
};
// MATCH (n:LABEL) RETURN n
@@ -186,9 +177,106 @@ auto load_queries(Db &db)
iter::for_all(label.index().for_range(t),
[&](auto a) { cout << a.at(prop_key) << endl; });
- return t.commit(), true;
+ return t.commit();
};
+ // MATCH (n) DELETE n
+ auto match_all_delete = [&db](const properties_t &args) {
+ DbAccessor t(db);
+
+ iter::for_all(t.vertex_access(), [&](auto a) {
+ if (a.fill()) {
+ a.remove();
+ }
+ });
+
+ return t.commit();
+ };
+
+ // MATCH (n:LABEL) DELETE n
+ auto match_label_delete = [&db](const properties_t &args) {
+ DbAccessor t(db);
+
+ auto &label = t.label_find_or_create("LABEL");
+
+ iter::for_all(label.index().for_range(t), [&](auto a) {
+ if (a.fill()) {
+ a.remove();
+ }
+ });
+
+ return t.commit();
+ };
+
+ // MATCH (n) WHERE ID(n) = id DELETE n
+ auto match_id_delete = [&db](const properties_t &args) {
+ DbAccessor t(db);
+
+ auto ov = t.vertex_find(args[0]->as<Int64>().value);
+ if (!option_fill(ov)) return t.commit(), false;
+
+ auto v = ov.take();
+ v.remove();
+
+ return t.commit();
+ };
+
+ // MATCH ()-[r]-() WHERE ID(r) = 0 DELETE r
+ auto match_edge_id_delete = [&db](const properties_t &args) {
+ DbAccessor t(db);
+
+ auto ov = t.edge_find(args[0]->as<Int64>().value);
+ if (!option_fill(ov)) return t.commit(), false;
+
+ auto v = ov.take();
+ v.remove();
+
+ return t.commit();
+ };
+
+ // MATCH ()-[r]-() DELETE r
+ auto match_edge_all_delete = [&db](const properties_t &args) {
+ DbAccessor t(db);
+
+ iter::for_all(t.edge_access(), [&](auto a) {
+ if (a.fill()) {
+ a.remove();
+ }
+ });
+
+ return t.commit();
+ };
+
+ // MATCH ()-[r:TYPE]-() DELETE r
+ auto match_edge_type_delete = [&db](const properties_t &args) {
+ DbAccessor t(db);
+
+ auto &type = t.type_find_or_create("TYPE");
+
+ iter::for_all(type.index().for_range(t), [&](auto a) {
+ if (a.fill()) {
+ a.remove();
+ }
+ });
+
+ return t.commit();
+ };
+
+ // MATCH ()-[r]-() WHERE ID(r) = 0 DELETE r
+ auto = [&db](const properties_t &args) {
+ DbAccessor t(db);
+
+ return t.commit();
+ };
+
+ // Blueprint:
+ // auto = [&db](const properties_t &args) {
+ // DbAccessor t(db);
+ //
+ //
+ // return t.commit();
+ // };
+
queries[15284086425088081497u] = match_all_nodes;
queries[4857652843629217005u] = match_by_label;
queries[15648836733456301916u] = create_edge_v2;
@@ -199,6 +287,12 @@ auto load_queries(Db &db)
queries[11198568396549106428u] = find_node_by_internal_id;
queries[8320600413058284114u] = find_edge_by_internal_id;
queries[6813335159006269041u] = update_node;
+ queries[10506105811763742758u] = match_all_delete;
+ queries[13742779491897528506u] = match_label_delete;
+ queries[11349462498691305864u] = match_id_delete;
+ queries[6963549500479100885u] = match_edge_id_delete;
+ queries[14897166600223619735u] = match_edge_all_delete;
+ queries[16888549834923624215u] = match_edge_type_delete;
return queries;
}
diff --git a/include/utils/iterator/filter.hpp b/include/utils/iterator/filter.hpp
new file mode 100644
index 000000000..ddbc45700
--- /dev/null
+++ b/include/utils/iterator/filter.hpp
@@ -0,0 +1,52 @@
+#pragma once
+
+#include "utils/iterator/iterator_base.hpp"
+#include "utils/option.hpp"
+
+namespace iter
+{
+
+// Class which maps values returned by I iterator into value of type T with OP
+// function.
+// T - type of return value
+// I - iterator type
+// OP - type of mapper function
+template <class T, class I, class OP>
+class Map : public IteratorBase<T>
+{
+
+public:
+ Map() = delete;
+
+ // Map operation is designed to be used in chained calls which operate on a
+ // iterator. Map will in that usecase receive other iterator by value and
+ // std::move is a optimization for it.
+ Map(I &&iter, OP &&op) : iter(std::move(iter)), op(std::move(op)) {}
+
+ Map(Map &&m) : iter(std::move(m.iter)), op(std::move(m.op)) {}
+
+ ~Map() final {}
+
+ Option<T> next() final
+ {
+ auto item = iter.next();
+ if (item.is_present()) {
+ return Option<T>(op(item.take()));
+ } else {
+ return Option<T>();
+ }
+ }
+
+private:
+ I iter;
+ OP op;
+};
+
+template <class I, class OP>
+auto make_map(I &&iter, OP &&op)
+{
+ // Compiler cant deduce type T. decltype is here to help with it.
+ return Map<decltype(op(iter.next().take())), I, OP>(std::move(iter),
+ std::move(op));
+}
+}
diff --git a/include/utils/iterator/for_all.hpp b/include/utils/iterator/for_all.hpp
index 043f2c882..d68344aff 100644
--- a/include/utils/iterator/for_all.hpp
+++ b/include/utils/iterator/for_all.hpp
@@ -25,4 +25,17 @@ void for_all(std::unique_ptr<I> &&iter, C &&consumer)
e = iter->next();
}
}
+
+template <class I, class C>
+void find(I iter, C &&consumer)
+{
+ auto e = iter.next();
+ while (e.is_present()) {
+
+ if (consumer(e.take())) {
+ return;
+ }
+ e = iter.next();
+ }
+}
}
diff --git a/poc/profile.hpp b/poc/profile.hpp
index 9e4548f21..0dea2abca 100644
--- a/poc/profile.hpp
+++ b/poc/profile.hpp
@@ -115,19 +115,6 @@ void for_all_fill(I iter, C &&consumer)
}
}
-template <class I, class C>
-void find(I iter, C &&consumer)
-{
- auto e = iter.next();
- while (e.is_present()) {
-
- if (consumer(e.take())) {
- return;
- }
- e = iter.next();
- }
-}
-
template <class I, class C>
void find_fill(I iter, C &&consumer)
{
diff --git a/src/barrier/barrier.cpp b/src/barrier/barrier.cpp
index 7031230bd..a2630d0a3 100644
--- a/src/barrier/barrier.cpp
+++ b/src/barrier/barrier.cpp
@@ -148,6 +148,8 @@ Option<const VertexAccessor> DbAccessor::vertex_find(const Id &id)
VertexAccessor DbAccessor::vertex_insert() { return CALL(vertex_insert()); }
+EdgeAccessIterator DbAccessor::edge_access() { return CALL(edge_access()); }
+
Option<const EdgeAccessor> DbAccessor::edge_find(const Id &id)
{
return HALF_CALL(edge_find(id)).map<const EdgeAccessor>();
@@ -467,6 +469,14 @@ Option<const VertexAccessor> VertexAccessIterator::next()
return HALF_CALL(next()).map<const VertexAccessor>();
}
+// ************************* EdgeAccessIterator
+DESTRUCTOR(EdgeAccessIterator, edge_access_iterator_t);
+
+Option<const EdgeAccessor> EdgeAccessIterator::next()
+{
+ return HALF_CALL(next()).map<const EdgeAccessor>();
+}
+
// ************************* VertexPropertyKey
DESTRUCTOR(VertexPropertyKey, PropertyFamilyKey);
@@ -596,7 +606,7 @@ void RecordStream<Stream>::write_fields(const std::vector<std::string> &fields)
}
template <class Stream>
-void RecordStream<Stream>::write_field(const std::string& field)
+void RecordStream<Stream>::write_field(const std::string &field)
{
HALF_CALL(write_field(field));
}
@@ -614,7 +624,7 @@ void RecordStream<Stream>::write_record()
}
template <class Stream>
-void RecordStream<Stream>::write_meta(const std::string& type)
+void RecordStream<Stream>::write_meta(const std::string &type)
{
HALF_CALL(write_meta(type));
}
@@ -632,7 +642,6 @@ void RecordStream<Stream>::chunk()
}
template class RecordStream<io::Socket>;
-
}
// **************************** ERROR EXAMPLES ****************************** //
From 57a3c053e82d564eedc2446047443e323f211418 Mon Sep 17 00:00:00 2001
From: Kruno Tomola Fabro <krunotf@memgraph.io>
Date: Tue, 30 Aug 2016 02:32:53 +0100
Subject: [PATCH 3/3] tmp commit
---
include/query_engine/hardcode/queries.hpp | 14 ++++++++++----
include/utils/iterator/filter.hpp | 22 ++++++++++++----------
2 files changed, 22 insertions(+), 14 deletions(-)
diff --git a/include/query_engine/hardcode/queries.hpp b/include/query_engine/hardcode/queries.hpp
index 11b7bfa5a..8d1a0c86b 100644
--- a/include/query_engine/hardcode/queries.hpp
+++ b/include/query_engine/hardcode/queries.hpp
@@ -221,7 +221,7 @@ auto load_queries(Db &db)
return t.commit();
};
- // MATCH ()-[r]-() WHERE ID(r) = 0 DELETE r
+ // MATCH ()-[r]-() WHERE ID(r) = id DELETE r
auto match_edge_id_delete = [&db](const properties_t &args) {
DbAccessor t(db);
@@ -262,11 +262,17 @@ auto load_queries(Db &db)
return t.commit();
};
- // MATCH ()-[r]-() WHERE ID(r) = 0 DELETE r
- auto = [&db](const properties_t &args) {
+ // MATCH (n)-[:TYPE]->(m) WHERE ID(n) = id RETURN m
+ auto match_type_id_return = [&db](const properties_t &args) {
DbAccessor t(db);
- return t.commit();
+ auto ov = t.vertex_find(args[0]->as<Int64>().value);
+ if (!option_fill(ov)) return t.commit(), false;
+ auto v = ov.take();
+
+ auto resoults = iter::make_f`
+
+ return t.commit();
};
// Blueprint:
diff --git a/include/utils/iterator/filter.hpp b/include/utils/iterator/filter.hpp
index ddbc45700..fc908f19c 100644
--- a/include/utils/iterator/filter.hpp
+++ b/include/utils/iterator/filter.hpp
@@ -6,26 +6,28 @@
namespace iter
{
-// Class which maps values returned by I iterator into value of type T with OP
+// Class which filters values returned by I iterator into value of type T with
+// OP
// function.
// T - type of return value
// I - iterator type
// OP - type of mapper function
template <class T, class I, class OP>
-class Map : public IteratorBase<T>
+class Filter : public IteratorBase<T>
{
public:
- Map() = delete;
+ Filter() = delete;
- // Map operation is designed to be used in chained calls which operate on a
- // iterator. Map will in that usecase receive other iterator by value and
+ // Filter operation is designed to be used in chained calls which operate on
+ // a
+ // iterator. Filter will in that usecase receive other iterator by value and
// std::move is a optimization for it.
- Map(I &&iter, OP &&op) : iter(std::move(iter)), op(std::move(op)) {}
+ Filter(I &&iter, OP &&op) : iter(std::move(iter)), op(std::move(op)) {}
- Map(Map &&m) : iter(std::move(m.iter)), op(std::move(m.op)) {}
+ Filter(Filter &&m) : iter(std::move(m.iter)), op(std::move(m.op)) {}
- ~Map() final {}
+ ~Filter() final {}
Option<T> next() final
{
@@ -46,7 +48,7 @@ template <class I, class OP>
auto make_map(I &&iter, OP &&op)
{
// Compiler cant deduce type T. decltype is here to help with it.
- return Map<decltype(op(iter.next().take())), I, OP>(std::move(iter),
- std::move(op));
+ return Filter<decltype(op(iter.next().take())), I, OP>(std::move(iter),
+ std::move(op));
}
}