From e356b1f4393b814873635254fd9df7b84b9b0001 Mon Sep 17 00:00:00 2001
From: Manish R Jain <manishrjain@gmail.com>
Date: Wed, 28 Oct 2015 17:28:02 +1100
Subject: [PATCH] Add parser to generate SubGraph. Should be a joyous moment,
don't feel it though :-).
---
gql/lexer.go | 16 ++++++
gql/lexer_test.go | 16 ++++++
gql/parser.go | 131 ++++++++++++++++++++++++++++++++++++++++++++
gql/parser_test.go | 134 +++++++++++++++++++++++++++++++++++++++++++++
gql/state.go | 16 ++++++
5 files changed, 313 insertions(+)
create mode 100644 gql/parser.go
create mode 100644 gql/parser_test.go
diff --git a/gql/lexer.go b/gql/lexer.go
index 4b1be185..3a30e4a7 100644
--- a/gql/lexer.go
+++ b/gql/lexer.go
@@ -1,3 +1,19 @@
+/*
+ * Copyright 2015 Manish R Jain <manishrjain@gmail.com>
+ *
+ * Licensed 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.
+ */
+
package gql
import (
diff --git a/gql/lexer_test.go b/gql/lexer_test.go
index 91ea5be5..0564b0c7 100644
--- a/gql/lexer_test.go
+++ b/gql/lexer_test.go
@@ -1,3 +1,19 @@
+/*
+ * Copyright 2015 Manish R Jain <manishrjain@gmail.com>
+ *
+ * Licensed 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.
+ */
+
package gql
import (
diff --git a/gql/parser.go b/gql/parser.go
new file mode 100644
index 00000000..5b3f2753
--- /dev/null
+++ b/gql/parser.go
@@ -0,0 +1,131 @@
+/*
+ * Copyright 2015 Manish R Jain <manishrjain@gmail.com>
+ *
+ * Licensed 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.
+ */
+
+package gql
+
+import (
+ "errors"
+ "fmt"
+ "strconv"
+
+ "github.com/manishrjain/dgraph/query"
+ "github.com/manishrjain/dgraph/x"
+)
+
+func Parse(input string) (sg *query.SubGraph, rerr error) {
+ l := newLexer(input)
+ sg = nil
+ for item := range l.items {
+ if item.typ == itemText {
+ continue
+ }
+ if item.typ == itemOpType {
+ if item.val == "mutation" {
+ return nil, errors.New("Mutations not supported")
+ }
+ }
+ if item.typ == itemLeftCurl {
+ if sg == nil {
+ sg, rerr = getRoot(l)
+ if rerr != nil {
+ x.Err(glog, rerr).Error("While retrieving subgraph root")
+ return nil, rerr
+ }
+ } else {
+ godeep(l, sg)
+ }
+ }
+ }
+ return sg, nil
+}
+
+func getRoot(l *lexer) (sg *query.SubGraph, rerr error) {
+ item := <-l.items
+ if item.typ != itemName {
+ return nil, fmt.Errorf("Expected some name. Got: %v", item)
+ }
+ // ignore itemName for now.
+ item = <-l.items
+ if item.typ != itemLeftRound {
+ return nil, fmt.Errorf("Expected variable start. Got: %v", item)
+ }
+
+ var uid uint64
+ var xid string
+ for {
+ var key, val string
+ // Get key or close bracket
+ item = <-l.items
+ if item.typ == itemArgName {
+ key = item.val
+ } else if item.typ == itemRightRound {
+ break
+ } else {
+ return nil, fmt.Errorf("Expecting argument name. Got: %v", item)
+ }
+
+ // Get corresponding value.
+ item = <-l.items
+ if item.typ == itemArgVal {
+ val = item.val
+ } else {
+ return nil, fmt.Errorf("Expecting argument val. Got: %v", item)
+ }
+
+ if key == "uid" {
+ uid, rerr = strconv.ParseUint(val, 0, 64)
+ if rerr != nil {
+ return nil, rerr
+ }
+ } else if key == "xid" {
+ xid = val
+ } else {
+ return nil, fmt.Errorf("Expecting uid or xid. Got: %v", item)
+ }
+ }
+ if item.typ != itemRightRound {
+ return nil, fmt.Errorf("Unexpected token. Got: %v", item)
+ }
+ return query.NewGraph(uid, xid)
+}
+
+func godeep(l *lexer, sg *query.SubGraph) {
+ curp := sg // stores current pointer.
+ for {
+ switch item := <-l.items; {
+ case item.typ == itemName:
+ child := new(query.SubGraph)
+ child.Attr = item.val
+ sg.Children = append(sg.Children, child)
+ curp = child
+ case item.typ == itemLeftCurl:
+ godeep(l, curp) // recursive iteration
+ case item.typ == itemRightCurl:
+ return
+ case item.typ == itemLeftRound:
+ // absorb all these, we don't care right now.
+ for {
+ item = <-l.items
+ if item.typ == itemRightRound || item.typ == itemEOF {
+ break
+ }
+ }
+ default:
+ // continue
+ }
+ }
+
+}
diff --git a/gql/parser_test.go b/gql/parser_test.go
new file mode 100644
index 00000000..e4dab4ee
--- /dev/null
+++ b/gql/parser_test.go
@@ -0,0 +1,134 @@
+/*
+ * Copyright 2015 Manish R Jain <manishrjain@gmail.com>
+ *
+ * Licensed 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.
+ */
+
+package gql
+
+import (
+ "fmt"
+ "testing"
+
+ "github.com/manishrjain/dgraph/query"
+)
+
+func checkAttr(g *query.SubGraph, attr string) error {
+ if g.Attr != attr {
+ return fmt.Errorf("Expected: %v. Got: %v", attr, g.Attr)
+ }
+ return nil
+}
+
+func TestParse(t *testing.T) {
+ query := `
+ query {
+ me(uid:0x0a) {
+ friends {
+ name
+ }
+ gender
+ age
+ hometown
+ }
+ }
+`
+
+ sg, err := Parse(query)
+ if err != nil {
+ t.Error(err)
+ }
+ if len(sg.Children) != 4 {
+ t.Errorf("Expected 4 children. Got: %v", len(sg.Children))
+ }
+ if err := checkAttr(sg.Children[0], "friends"); err != nil {
+ t.Error(err)
+ }
+ if err := checkAttr(sg.Children[1], "gender"); err != nil {
+ t.Error(err)
+ }
+ if err := checkAttr(sg.Children[2], "age"); err != nil {
+ t.Error(err)
+ }
+ if err := checkAttr(sg.Children[3], "hometown"); err != nil {
+ t.Error(err)
+ }
+ child := sg.Children[0]
+ if len(child.Children) != 1 {
+ t.Errorf("Expected 1 child of friends. Got: %v", len(child.Children))
+ }
+ if err := checkAttr(child.Children[0], "name"); err != nil {
+ t.Error(err)
+ }
+}
+
+func TestParse_error1(t *testing.T) {
+ query := `
+ mutation {
+ me(uid:0x0a) {
+ name
+ }
+ }
+ `
+ var err error
+ _, err = Parse(query)
+ t.Log(err)
+ if err == nil {
+ t.Error("Expected error")
+ }
+}
+
+func TestParse_error2(t *testing.T) {
+ query := `
+ query {
+ me {
+ name
+ }
+ }
+ `
+ var err error
+ _, err = Parse(query)
+ t.Log(err)
+ if err == nil {
+ t.Error("Expected error")
+ }
+}
+
+func TestParse_pass1(t *testing.T) {
+ query := `
+ {
+ me(uid:0x0a) {
+ name,
+ friends(xid:what) { # xid would be ignored.
+ }
+ }
+ }
+ `
+ sg, err := Parse(query)
+ if err != nil {
+ t.Error(err)
+ }
+ if len(sg.Children) != 2 {
+ t.Errorf("Expected 2. Got: %v", len(sg.Children))
+ }
+ if err := checkAttr(sg.Children[0], "name"); err != nil {
+ t.Error(err)
+ }
+ if err := checkAttr(sg.Children[1], "friends"); err != nil {
+ t.Error(err)
+ }
+ f := sg.Children[1]
+ if len(f.Children) != 0 {
+ t.Errorf("Expected 0. Got: %v", len(sg.Children))
+ }
+}
diff --git a/gql/state.go b/gql/state.go
index 01e967ea..f5e07c04 100644
--- a/gql/state.go
+++ b/gql/state.go
@@ -1,3 +1,19 @@
+/*
+ * Copyright 2015 Manish R Jain <manishrjain@gmail.com>
+ *
+ * Licensed 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.
+ */
+
package gql
const (
--
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