support for arrays

graphql.go

@@ -41,6 +41,12 @@ func exec(s *Schema, t schema.Type, sel *query.SelectionSet, resolver reflect.Va
 	switch t := t.(type) {
 	case *schema.Scalar:
 		return resolver.Interface()
+	case *schema.Array:
+		a := make([]interface{}, resolver.Len())
+		for i := range a {
+			a[i] = exec(s, t.Elem, sel, resolver.Index(i))
+		}
+		return a
 	case *schema.TypeName:
 		return exec(s, s.Types[t.Name], sel, resolver)
 	case *schema.Object:

graphql_test.go

@@ -15,12 +15,21 @@ func (r *helloWorldResolver) Hello() string {
 type starWarsResolver struct{}
 
 func (r *starWarsResolver) Hero() *userResolver {
-	return &userResolver{id: "2001", name: "R2-D2"}
+	return &userResolver{
+		id:   "2001",
+		name: "R2-D2",
+		friends: []*userResolver{
+			{name: "Luke Skywalker"},
+			{name: "Han Solo"},
+			{name: "Leia Organa"},
+		},
+	}
 }
 
 type userResolver struct {
-	id   string
-	name string
+	id      string
+	name    string
+	friends []*userResolver
 }
 
 func (r *userResolver) ID() string {
@@ -31,6 +40,10 @@ func (r *userResolver) Name() string {
 	return r.name
 }
 
+func (r *userResolver) Friends() []*userResolver {
+	return r.friends
+}
+
 var tests = []struct {
 	name     string
 	schema   string
@@ -58,7 +71,7 @@ var tests = []struct {
 		`,
 	},
 	{
-		name: "User",
+		name: "StarWars",
 		schema: `
 			type Query {
 				hero: User
@@ -67,6 +80,7 @@ var tests = []struct {
 			type User {
 				id: String
 				name: String
+				friends: [User]
 			}
 		`,
 		resolver: &starWarsResolver{},
@@ -75,14 +89,28 @@ var tests = []struct {
 				hero {
 					id
 					name
+					friends {
+						name
+					}
 				}
 			}
 		`,
 		result: `
 			{
 				"hero": {
 					"id": "2001",
-					"name": "R2-D2"
+					"name": "R2-D2",
+					"friends": [
+						{
+							"name": "Luke Skywalker"
+						},
+						{
+							"name": "Han Solo"
+						},
+						{
+							"name": "Leia Organa"
+						}
+					]
 				}
 			}
 		`,

internal/schema/schema.go

@@ -17,6 +17,10 @@ type Type interface{}
 type Scalar struct {
 }
 
+type Array struct {
+	Elem Type
+}
+
 type TypeName struct {
 	Name string
 }
@@ -79,8 +83,10 @@ func parseTypeDecl(l *lexer.Lexer) (string, *Object) {
 }
 
 func parseType(l *lexer.Lexer) Type {
-	// TODO check args
-	// TODO check return type
+	if l.Peek() == '[' {
+		return parseArray(l)
+	}
+
 	name := l.ConsumeIdent()
 	if name == "String" {
 		return &Scalar{}
@@ -89,3 +95,10 @@ func parseType(l *lexer.Lexer) Type {
 		Name: name,
 	}
 }
+
+func parseArray(l *lexer.Lexer) *Array {
+	l.ConsumeToken('[')
+	elem := parseType(l)
+	l.ConsumeToken(']')
+	return &Array{Elem: elem}
+}