LinkedQL: Project Step

query/linkedql/registry.go

@@ -187,34 +187,36 @@ func Unmarshal(data []byte) (RegistryItem, error) {
 			}
 			fv.Set(reflect.ValueOf(s))
 		case reflect.Slice:
-			el := f.Type.Elem()
-			if el.Kind() != reflect.Interface {
-				err := json.Unmarshal(v, fv.Addr().Interface())
-				if err != nil {
+			var arr []json.RawMessage
+			err := json.Unmarshal(v, &arr)
+			if err != nil {
+				var i json.RawMessage
+				iErr := json.Unmarshal(v, &i)
+				if iErr != nil {
 					return nil, err
 				}
-			} else {
-				var arr []json.RawMessage
-				err := json.Unmarshal(v, &arr)
-				if err != nil {
-					var i json.RawMessage
-					iErr := json.Unmarshal(v, &i)
-					if iErr != nil {
-						return nil, err
-					}
-					arr = []json.RawMessage{i}
-				}
-				if arr != nil {
-					va := reflect.MakeSlice(f.Type, len(arr), len(arr))
-					for i, v := range arr {
+				arr = []json.RawMessage{i}
+			}
+			if arr != nil {
+				el := f.Type.Elem()
+				va := reflect.MakeSlice(f.Type, len(arr), len(arr))
+				for i, v := range arr {
+					if el.Kind() != reflect.Interface {
+						new := reflect.New(el)
+						err := json.Unmarshal(v, new.Interface())
+						if err != nil {
+							return nil, err
+						}
+						va.Index(i).Set(new.Elem())
+					} else {
 						s, err := Unmarshal(v)
 						if err != nil {
 							return nil, err
 						}
 						va.Index(i).Set(reflect.ValueOf(s))
 					}
-					fv.Set(va)
 				}
+				fv.Set(va)
 			}
 		default:
 			err := json.Unmarshal(v, fv.Addr().Interface())

query/linkedql/steps/project.go

@@ -0,0 +1,47 @@
+package steps
+
+import (
+	"github.com/cayleygraph/cayley/graph"
+	"github.com/cayleygraph/cayley/query"
+	"github.com/cayleygraph/cayley/query/linkedql"
+	"github.com/cayleygraph/cayley/query/path"
+	"github.com/cayleygraph/quad"
+	"github.com/cayleygraph/quad/voc"
+)
+
+func init() {
+	linkedql.Register(&Project{})
+}
+
+var _ linkedql.IteratorStep = (*Project)(nil)
+var _ linkedql.PathStep = (*Project)(nil)
+
+// Project corresponds to .project().
+type Project struct {
+	From linkedql.PathStep `json:"from"`
+	Name quad.IRI          `json:"name"`
+	Step linkedql.PathStep `json:"step"`
+}
+
+// Description implements Step.
+func (s *Project) Description() string {
+	return "Sets the result of step to name"
+}
+
+// BuildIterator implements linkedql.IteratorStep.
+func (s *Project) BuildIterator(qs graph.QuadStore, ns *voc.Namespaces) (query.Iterator, error) {
+	return linkedql.NewValueIteratorFromPathStep(s, qs, ns)
+}
+
+// BuildPath implements linkedql.PathStep.
+func (s *Project) BuildPath(qs graph.QuadStore, ns *voc.Namespaces) (*path.Path, error) {
+	fromPath, err := s.From.BuildPath(qs, ns)
+	if err != nil {
+		return nil, err
+	}
+	step, err := s.Step.BuildPath(qs, ns)
+	if err != nil {
+		return nil, err
+	}
+	return fromPath.Follow(step).Tag(string(s.Name)).And(fromPath), nil
+}

query/linkedql/steps/steps_test.go

@@ -90,6 +90,9 @@ func TestLinkedQL(t *testing.T) {
 			for iterator.Next(ctx) {
 				results = append(results, iterator.Result())
 			}
+			if testName == "project" {
+				fmt.Printf("Results: %#v\n", results)
+			}
 			require.NoError(t, iterator.Err())
 			require.Equal(t, nil, isomorphic(c.Results, results))
 		})

query/linkedql/steps/test-cases/Select.json

@@ -2,11 +2,10 @@
   "data": [
     {
       "@id": "http://example.com/alice",
-      "http://example.com/likes": [
-        {
-          "@id": "http://example.com/bob"
-        }
-      ]
+      "http://example.com/likes": {
+        "@id": "http://example.com/bob"
+      },
+      "http://example.com/name": "Alice"
     }
   ],
   "query": {
@@ -15,21 +14,21 @@
     },
     "@type": "Select",
     "from": {
-      "@type": "Visit",
+      "@type": "Properties",
+      "names": ["http://example.com/likes", "http://example.com/name"],
       "from": {
-        "@type": "As",
-        "from": { "@type": "Match", "pattern": {} },
-        "name": "http://example.com/liker"
-      },
-      "properties": "http://example.com/likes"
+        "@type": "Match",
+        "pattern": {}
+      }
     },
-    "tags": []
+    "properties": []
   },
   "results": [
     {
-      "http://example.com/liker": {
-        "@id": "http://example.com/alice"
-      }
+      "http://example.com/likes": {
+        "@id": "http://example.com/bob"
+      },
+      "http://example.com/name": "Alice"
     }
   ]
 }

query/linkedql/steps/test-cases/reverse-property-names-as.json → query/linkedql/steps/test-cases/project.json

@@ -6,26 +6,30 @@
         {
           "@id": "http://example.com/bob"
         }
-      ]
+      ],
+      "http://example.com/name": "Alice"
     }
   ],
   "query": {
     "@context": {
       "@vocab": "http://cayley.io/linkedql#"
     },
-    "@type": "Select",
-    "from": {
-      "@type": "ReversePropertyNamesAs",
-      "from": { "@type": "Match", "pattern": {} },
-      "tag": "property"
+    "@type": "Project",
+    "name": "http://example.com/total",
+    "step": {
+      "@type": "Count",
+      "from": {
+        "@type": "Placeholder"
+      }
     },
-    "tags": []
+    "from": {
+      "@type": "Match",
+      "pattern": {}
+    }
   },
   "results": [
     {
-      "property": {
-        "@id": "http://example.com/likes"
-      }
+      "http://example.com/total": 7
     }
   ]
 }

query/linkedql/steps/test-cases/property-names.json

@@ -6,7 +6,8 @@
         {
           "@id": "http://example.com/bob"
         }
-      ]
+      ],
+      "http://example.com/name": "Alice"
     }
   ],
   "query": {
@@ -19,6 +20,9 @@
   "results": [
     {
       "@id": "http://example.com/likes"
+    },
+    {
+      "@id": "http://example.com/name"
     }
   ]
 }

query/linkedql/steps/test-cases/select-with-properties.json

@@ -0,0 +1,33 @@
+{
+  "data": [
+    {
+      "@id": "http://example.com/alice",
+      "http://example.com/likes": {
+        "@id": "http://example.com/bob"
+      },
+      "http://example.com/name": "Alice"
+    }
+  ],
+  "query": {
+    "@context": {
+      "@vocab": "http://cayley.io/linkedql#"
+    },
+    "@type": "Select",
+    "from": {
+      "@type": "Properties",
+      "names": ["http://example.com/likes", "http://example.com/name"],
+      "from": {
+        "@type": "Match",
+        "pattern": {}
+      }
+    },
+    "properties": ["http://example.com/likes"]
+  },
+  "results": [
+    {
+      "http://example.com/likes": {
+        "@id": "http://example.com/bob"
+      }
+    }
+  ]
+}