Implement map projection

Adds support for openCypher Map Projection specification.

Makefile

@@ -102,7 +102,7 @@ REGRESS = scan \
           cypher_union \
           cypher_call \
           cypher_merge \
-	  cypher_subquery \
+          cypher_subquery \
           age_global_graph \
           age_load \
           index \
@@ -111,6 +111,7 @@ REGRESS = scan \
           name_validation \
           jsonb_operators \
           list_comprehension \
+          map_projection \
           drop
 
 srcdir=`pwd`

regress/expected/map_projection.out

@@ -0,0 +1,171 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+LOAD 'age';
+SET search_path TO ag_catalog;
+SELECT create_graph('map_proj');
+NOTICE:  graph "map_proj" has been created
+ create_graph 
+--------------
+
+(1 row)
+
+SELECT * FROM cypher('map_proj',
+$$
+    CREATE
+        (tom:Actor {name:'Tom Hanks', age:60}),
+        (bale:Actor {name:'Christian Bale', age:50}),
+        (tom)-[:ACTED_IN {during: 1990}]->(:Movie {title:'Forrest Gump'}),
+        (tom)-[:ACTED_IN {during: 1995}]->(:Movie {title:'Finch'}),
+        (tom)-[:ACTED_IN {during: 1999}]->(:Movie {title:'The Circle'}),
+        (bale)-[:ACTED_IN {during: 2002}]->(:Movie {title:'The Prestige'}),
+        (bale)-[:ACTED_IN {during: 2008}]->(:Movie {title:'The Dark Knight'})
+$$) as (a agtype);
+ a 
+---
+(0 rows)
+
+-- all property selection
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map RETURN map { .* } $$) as (a agtype);
+             a              
+----------------------------
+ {"age": 50, "name": "Bob"}
+(1 row)
+
+-- property selector
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map RETURN map { .name } $$) as (a agtype);
+        a        
+-----------------
+ {"name": "Bob"}
+(1 row)
+
+-- literal entry
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map RETURN map { name:'Tom' } $$) as (a agtype);
+        a        
+-----------------
+ {"name": "Tom"}
+(1 row)
+
+-- variable selector
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map, 'Tom' as name RETURN map { name } $$) as (a agtype);
+        a        
+-----------------
+ {"name": "Tom"}
+(1 row)
+
+-- duplicate all property selector
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map RETURN map { .*, .* } $$) as (a agtype);
+             a              
+----------------------------
+ {"age": 50, "name": "Bob"}
+(1 row)
+
+-- name being selected twice
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map RETURN map { .name, .* } $$) as (a agtype);
+             a              
+----------------------------
+ {"age": 50, "name": "Bob"}
+(1 row)
+
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map RETURN map { .name, .name } $$) as (a agtype);
+        a        
+-----------------
+ {"name": "Bob"}
+(1 row)
+
+-- name being selected twice with different value
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map RETURN map { name:'Tom', .* } $$) as (a agtype);
+             a              
+----------------------------
+ {"age": 50, "name": "Tom"}
+(1 row)
+
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map, 'Tom' as name RETURN map { name, .* } $$) as (a agtype);
+             a              
+----------------------------
+ {"age": 50, "name": "Tom"}
+(1 row)
+
+-- new entry added
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map RETURN map { .name, .age, height:180 } $$) as (a agtype);
+                     a                     
+-------------------------------------------
+ {"age": 50, "name": "Bob", "height": 180}
+(1 row)
+
+-- NULL as a map
+SELECT * FROM cypher('map_proj', $$ WITH NULL AS map RETURN map { .name } $$) as (a agtype);
+ a  
+----
+ {}
+(1 row)
+
+-- vertex as a map
+SELECT * FROM cypher('map_proj', $$ MATCH (n:Actor) RETURN n { .name } $$) as (a agtype);
+             a              
+----------------------------
+ {"name": "Tom Hanks"}
+ {"name": "Christian Bale"}
+(2 rows)
+
+-- edge as a map
+SELECT * FROM cypher('map_proj', $$ MATCH ()-[e:ACTED_IN]->() RETURN e { .during } $$) as (a agtype);
+        a         
+------------------
+ {"during": 1990}
+ {"during": 1995}
+ {"during": 1999}
+ {"during": 2002}
+ {"during": 2008}
+(5 rows)
+
+-- syntax error
+SELECT * FROM cypher('map_proj', $$ WITH 12 AS map RETURN map { .name } $$) as (a agtype);
+ERROR:  properties() argument must be a vertex, an edge or null
+SELECT * FROM cypher('map_proj', $$ WITH [] AS map RETURN map { .name } $$) as (a agtype);
+ERROR:  properties() argument must resolve to an object
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob'} AS map RETURN map { 'name' } $$) as (a agtype);
+ERROR:  syntax error at or near "'name'"
+LINE 1: ...p_proj', $$ WITH {name:'Bob'} AS map RETURN map { 'name' } $...
+                                                             ^
+-- advanced
+SELECT * FROM cypher('map_proj',
+$$
+    MATCH (a:Actor)-[:ACTED_IN]->(m:Movie)
+    WITH a, collect(m { .title }) AS movies
+    RETURN collect(a { .name, movies })
+$$) as (a agtype);
+                                                                                                      a                                                                                                       
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ [{"name": "Christian Bale", "movies": [{"title": "The Prestige"}, {"title": "The Dark Knight"}]}, {"name": "Tom Hanks", "movies": [{"title": "Forrest Gump"}, {"title": "Finch"}, {"title": "The Circle"}]}]
+(1 row)
+
+-- drop
+SELECT drop_graph('map_proj', true);
+NOTICE:  drop cascades to 5 other objects
+DETAIL:  drop cascades to table map_proj._ag_label_vertex
+drop cascades to table map_proj._ag_label_edge
+drop cascades to table map_proj."Actor"
+drop cascades to table map_proj."ACTED_IN"
+drop cascades to table map_proj."Movie"
+NOTICE:  graph "map_proj" has been dropped
+ drop_graph 
+------------
+
+(1 row)
+

regress/sql/map_projection.sql

@@ -0,0 +1,74 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+LOAD 'age';
+SET search_path TO ag_catalog;
+
+SELECT create_graph('map_proj');
+
+SELECT * FROM cypher('map_proj',
+$$
+    CREATE
+        (tom:Actor {name:'Tom Hanks', age:60}),
+        (bale:Actor {name:'Christian Bale', age:50}),
+        (tom)-[:ACTED_IN {during: 1990}]->(:Movie {title:'Forrest Gump'}),
+        (tom)-[:ACTED_IN {during: 1995}]->(:Movie {title:'Finch'}),
+        (tom)-[:ACTED_IN {during: 1999}]->(:Movie {title:'The Circle'}),
+        (bale)-[:ACTED_IN {during: 2002}]->(:Movie {title:'The Prestige'}),
+        (bale)-[:ACTED_IN {during: 2008}]->(:Movie {title:'The Dark Knight'})
+$$) as (a agtype);
+
+-- all property selection
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map RETURN map { .* } $$) as (a agtype);
+-- property selector
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map RETURN map { .name } $$) as (a agtype);
+-- literal entry
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map RETURN map { name:'Tom' } $$) as (a agtype);
+-- variable selector
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map, 'Tom' as name RETURN map { name } $$) as (a agtype);
+-- duplicate all property selector
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map RETURN map { .*, .* } $$) as (a agtype);
+-- name being selected twice
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map RETURN map { .name, .* } $$) as (a agtype);
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map RETURN map { .name, .name } $$) as (a agtype);
+-- name being selected twice with different value
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map RETURN map { name:'Tom', .* } $$) as (a agtype);
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map, 'Tom' as name RETURN map { name, .* } $$) as (a agtype);
+-- new entry added
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob', age:50} AS map RETURN map { .name, .age, height:180 } $$) as (a agtype);
+-- NULL as a map
+SELECT * FROM cypher('map_proj', $$ WITH NULL AS map RETURN map { .name } $$) as (a agtype);
+-- vertex as a map
+SELECT * FROM cypher('map_proj', $$ MATCH (n:Actor) RETURN n { .name } $$) as (a agtype);
+-- edge as a map
+SELECT * FROM cypher('map_proj', $$ MATCH ()-[e:ACTED_IN]->() RETURN e { .during } $$) as (a agtype);
+-- syntax error
+SELECT * FROM cypher('map_proj', $$ WITH 12 AS map RETURN map { .name } $$) as (a agtype);
+SELECT * FROM cypher('map_proj', $$ WITH [] AS map RETURN map { .name } $$) as (a agtype);
+SELECT * FROM cypher('map_proj', $$ WITH {name:'Bob'} AS map RETURN map { 'name' } $$) as (a agtype);
+-- advanced
+SELECT * FROM cypher('map_proj',
+$$
+    MATCH (a:Actor)-[:ACTED_IN]->(m:Movie)
+    WITH a, collect(m { .title }) AS movies
+    RETURN collect(a { .name, movies })
+$$) as (a agtype);
+
+-- drop
+SELECT drop_graph('map_proj', true);

src/backend/nodes/ag_nodes.c

@@ -45,6 +45,8 @@ const char *node_names[] = {
     "cypher_bool_const",
     "cypher_param",
     "cypher_map",
+    "cypher_map_projection",
+    "cypher_map_projection_element",
     "cypher_list",
     "cypher_comparison_aexpr",
     "cypher_comparison_boolexpr",
@@ -111,6 +113,7 @@ const ExtensibleNodeMethods node_methods[] = {
     DEFINE_NODE_METHODS(cypher_bool_const),
     DEFINE_NODE_METHODS(cypher_param),
     DEFINE_NODE_METHODS(cypher_map),
+    DEFINE_NODE_METHODS(cypher_map_projection),
     DEFINE_NODE_METHODS(cypher_list),
     DEFINE_NODE_METHODS(cypher_comparison_aexpr),
     DEFINE_NODE_METHODS(cypher_comparison_boolexpr),

src/backend/nodes/cypher_outfuncs.c

@@ -251,6 +251,15 @@ void out_cypher_map(StringInfo str, const ExtensibleNode *node)
     WRITE_LOCATION_FIELD(location);
 }
 
+void out_cypher_map_projection(StringInfo str, const ExtensibleNode *node)
+{
+    DEFINE_AG_NODE(cypher_map_projection);
+
+    WRITE_NODE_FIELD(map_var);
+    WRITE_NODE_FIELD(map_elements);
+    WRITE_LOCATION_FIELD(location);
+}
+
 // serialization function for the cypher_list ExtensibleNode.
 void out_cypher_list(StringInfo str, const ExtensibleNode *node)
 {