improved support for arguments

graphql.go

@@ -52,17 +52,22 @@ func exec(s *Schema, t schema.Type, sel *query.SelectionSet, resolver reflect.Va
 	case *schema.Object:
 		res := make(map[string]interface{})
 		for _, f := range sel.Selections {
+			sf := t.Fields[f.Name]
 			m := resolver.Method(findMethod(resolver.Type(), f.Name))
 			var in []reflect.Value
-			if len(f.Arguments) != 0 {
-				args := reflect.New(m.Type().In(0).Elem())
-				for name, value := range f.Arguments {
-					f := args.Elem().FieldByNameFunc(func(n string) bool { return strings.EqualFold(n, name) })
-					f.Set(reflect.ValueOf(value.Value))
+			if len(sf.Parameters) != 0 {
+				args := reflect.New(m.Type().In(0))
+				for name, param := range sf.Parameters {
+					value, ok := f.Arguments[name]
+					if !ok {
+						value = &query.Value{Value: param.Default}
+					}
+					rf := args.Elem().FieldByNameFunc(func(n string) bool { return strings.EqualFold(n, name) })
+					rf.Set(reflect.ValueOf(value.Value))
 				}
-				in = []reflect.Value{args}
+				in = []reflect.Value{args.Elem()}
 			}
-			res[f.Name] = exec(s, t.Fields[f.Name].Type, f.Sel, m.Call(in)[0])
+			res[f.Name] = exec(s, sf.Type, f.Sel, m.Call(in)[0])
 		}
 		return res
 	}

graphql_test.go

@@ -279,11 +279,12 @@ func init() {
 
 type starWarsResolver struct{}
 
-func (r *starWarsResolver) Hero() characterResolver {
+func (r *starWarsResolver) Hero(args struct{ Episode string }) characterResolver {
+	// TODO episode
 	return &droidResolver{droidData["2001"]}
 }
 
-func (r *starWarsResolver) Human(args *struct{ ID string }) *humanResolver {
+func (r *starWarsResolver) Human(args struct{ ID string }) *humanResolver {
 	h := humanData[args.ID]
 	if h == nil {
 		return nil
@@ -309,8 +310,15 @@ func (r *humanResolver) Name() string {
 	return r.h.Name
 }
 
-func (r *humanResolver) Height() float64 {
-	return r.h.Height
+func (r *humanResolver) Height(args struct{ Unit string }) float64 {
+	switch args.Unit {
+	case "METER":
+		return r.h.Height
+	case "FOOT":
+		return r.h.Height * 3.28084
+	default:
+		panic("invalid unit")
+	}
 }
 
 func (r *humanResolver) Friends() []characterResolver {
@@ -373,7 +381,7 @@ var tests = []struct {
 		`,
 	},
 	{
-		name:     "StarWars1",
+		name:     "StarWarsBasic",
 		schema:   starWarsSchema,
 		resolver: &starWarsResolver{},
 		query: `
@@ -408,7 +416,7 @@ var tests = []struct {
 		`,
 	},
 	{
-		name:     "StarWars2",
+		name:     "StarWarsArguments1",
 		schema:   starWarsSchema,
 		resolver: &starWarsResolver{},
 		query: `
@@ -428,6 +436,27 @@ var tests = []struct {
 			}
 		`,
 	},
+	{
+		name:     "StarWarsArguments2",
+		schema:   starWarsSchema,
+		resolver: &starWarsResolver{},
+		query: `
+			{
+				human(id: "1000") {
+					name
+					height(unit: FOOT)
+				}
+			}
+		`,
+		result: `
+			{
+				"human": {
+					"name": "Luke Skywalker",
+					"height": 5.6430448
+				}
+			}
+		`,
+	},
 }
 
 func TestAll(t *testing.T) {

internal/query/query.go

@@ -82,7 +82,28 @@ func parseArgument(l *lexer.Lexer) (string, *Value) {
 	return name, value
 }
 
+type ValueType int
+
+const (
+	Int ValueType = iota
+	Float
+	String
+	Boolean
+	Enum
+)
+
 func parseValue(l *lexer.Lexer) *Value {
-	value := l.ConsumeString()
-	return &Value{Value: value}
+	switch l.Peek() {
+	case scanner.String:
+		return &Value{
+			Value: l.ConsumeString(),
+		}
+	case scanner.Ident:
+		return &Value{
+			Value: l.ConsumeIdent(),
+		}
+	default:
+		l.SyntaxError("invalid value")
+		panic("unreachable")
+	}
 }

internal/schema/schema.go

@@ -33,10 +33,16 @@ type Object struct {
 
 type Field struct {
 	Name       string
-	Parameters map[string]string
+	Parameters map[string]*Parameter
 	Type       Type
 }
 
+type Parameter struct {
+	Name    string
+	Type    string
+	Default string
+}
+
 func Parse(schemaString string, filename string) (res *Schema, errRes error) {
 	sc := &scanner.Scanner{
 		Mode: scanner.ScanIdents | scanner.ScanFloats | scanner.ScanStrings,
@@ -144,18 +150,18 @@ func parseInputDecl(l *lexer.Lexer) {
 
 func parseField(l *lexer.Lexer) *Field {
 	f := &Field{
-		Parameters: make(map[string]string),
+		Parameters: make(map[string]*Parameter),
 	}
 	f.Name = l.ConsumeIdent()
 	if l.Peek() == '(' {
 		l.ConsumeToken('(')
 		if l.Peek() != ')' {
-			name, typ := parseParameter(l)
-			f.Parameters[name] = typ
+			p := parseParameter(l)
+			f.Parameters[p.Name] = p
 			for l.Peek() != ')' {
 				l.ConsumeToken(',')
-				name, typ := parseParameter(l)
-				f.Parameters[name] = typ
+				p := parseParameter(l)
+				f.Parameters[p.Name] = p
 			}
 		}
 		l.ConsumeToken(')')
@@ -168,18 +174,19 @@ func parseField(l *lexer.Lexer) *Field {
 	return f
 }
 
-func parseParameter(l *lexer.Lexer) (string, string) {
-	name := l.ConsumeIdent()
+func parseParameter(l *lexer.Lexer) *Parameter {
+	p := &Parameter{}
+	p.Name = l.ConsumeIdent()
 	l.ConsumeToken(':')
-	typ := l.ConsumeIdent()
+	p.Type = l.ConsumeIdent()
 	if l.Peek() == '!' {
 		l.ConsumeToken('!') // TODO
 	}
 	if l.Peek() == '=' {
 		l.ConsumeToken('=')
-		l.ConsumeIdent() // TODO
+		p.Default = l.ConsumeIdent()
 	}
-	return name, typ
+	return p
 }
 
 func parseType(l *lexer.Lexer) Type {