refactor: improved type system

99designs · Oct 25, 2016 · 4fd3395 · 4fd3395
1 parent 1d03e66
commit 4fd3395
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Showing 3 changed files with 31 additions and 49 deletions.
diff --git a/internal/common/common.go b/internal/common/common.go
@@ -3,7 +3,7 @@ package common
 import "github.com/neelance/graphql-go/internal/lexer"
 
 type Type interface {
-	IsType()
+	Kind() string
 }
 
 type List struct {
@@ -18,9 +18,9 @@ type TypeName struct {
 	Name string
 }
 
-func (*List) IsType()     {}
-func (*NonNull) IsType()  {}
-func (*TypeName) IsType() {}
+func (*List) Kind() string     { return "LIST" }
+func (*NonNull) Kind() string  { return "NON_NULL" }
+func (*TypeName) Kind() string { panic("TypeName needs to be resolved to actual type") }
 
 func ParseType(l *lexer.Lexer) Type {
 	t := parseNullType(l)

diff --git a/internal/exec/introspection.go b/internal/exec/introspection.go
@@ -254,45 +254,15 @@ type typeResolver struct {
 }
 
 func (r *typeResolver) Kind() string {
-	switch r.typ.(type) {
-	case *schema.Scalar:
-		return "SCALAR"
-	case *schema.Object:
-		return "OBJECT"
-	case *schema.Interface:
-		return "INTERFACE"
-	case *schema.Union:
-		return "UNION"
-	case *schema.Enum:
-		return "ENUM"
-	case *schema.InputObject:
-		return "INPUT_OBJECT"
-	case *common.List:
-		return "LIST"
-	case *common.NonNull:
-		return "NON_NULL"
-	default:
-		panic("unreachable")
-	}
+	return r.typ.Kind()
 }
 
 func (r *typeResolver) Name() *string {
-	switch t := r.typ.(type) {
-	case *schema.Scalar:
-		return &t.Name
-	case *schema.Object:
-		return &t.Name
-	case *schema.Interface:
-		return &t.Name
-	case *schema.Union:
-		return &t.Name
-	case *schema.Enum:
-		return &t.Name
-	case *schema.InputObject:
-		return &t.Name
-	default:
-		return nil
+	if named, ok := r.typ.(schema.NamedType); ok {
+		name := named.TypeName()
+		return &name
 	}
+	return nil
 }
 
 func (r *typeResolver) Description() *string {

diff --git a/internal/schema/schema.go b/internal/schema/schema.go
@@ -11,14 +11,19 @@ import (
 )
 
 type Schema struct {
-	EntryPoints map[string]common.Type
-	Types       map[string]common.Type
+	EntryPoints map[string]NamedType
+	Types       map[string]NamedType
 
 	entryPointNames map[string]string
 	objects         []*Object
 	unions          []*Union
 }
 
+type NamedType interface {
+	common.Type
+	TypeName() string
+}
+
 type Scalar struct {
 	Name string
 }
@@ -57,12 +62,19 @@ type InputObject struct {
 	InputFieldOrder []string
 }
 
-func (*Scalar) IsType()      {}
-func (*Object) IsType()      {}
-func (*Interface) IsType()   {}
-func (*Union) IsType()       {}
-func (*Enum) IsType()        {}
-func (*InputObject) IsType() {}
+func (*Scalar) Kind() string      { return "SCALAR" }
+func (*Object) Kind() string      { return "OBJECT" }
+func (*Interface) Kind() string   { return "INTERFACE" }
+func (*Union) Kind() string       { return "UNION" }
+func (*Enum) Kind() string        { return "ENUM" }
+func (*InputObject) Kind() string { return "INPUT_OBJECT" }
+
+func (t *Scalar) TypeName() string      { return t.Name }
+func (t *Object) TypeName() string      { return t.Name }
+func (t *Interface) TypeName() string   { return t.Name }
+func (t *Union) TypeName() string       { return t.Name }
+func (t *Enum) TypeName() string        { return t.Name }
+func (t *InputObject) TypeName() string { return t.Name }
 
 type Field struct {
 	Name     string
@@ -97,7 +109,7 @@ func Parse(schemaString string) (s *Schema, err *errors.GraphQLError) {
 		}
 	}
 
-	s.EntryPoints = make(map[string]common.Type)
+	s.EntryPoints = make(map[string]NamedType)
 	for key, name := range s.entryPointNames {
 		t, ok := s.Types[name]
 		if !ok {
@@ -216,7 +228,7 @@ func resolveTypeName(s *Schema, t common.Type) (common.Type, *errors.GraphQLErro
 func parseSchema(l *lexer.Lexer) *Schema {
 	s := &Schema{
 		entryPointNames: make(map[string]string),
-		Types: map[string]common.Type{
+		Types: map[string]NamedType{
 			"Int":     &Scalar{Name: "Int"},
 			"Float":   &Scalar{Name: "Float"},
 			"String":  &Scalar{Name: "String"},