add types package

Part of graph-gophers#434 and related to graph-gophers#116 this change adds a new package containing all
types used by graphql-go in representing the GraphQL specification. The names
used in this package should match the specification as closely as possible.

In order to have cohesion, all internal packages that use GraphQL types have
been changed to use this new package.

This change is large but mostly mechanical. I recommend starting by reading
through the `types` package to build familiarity. I'll call out places in the
code where I made decisions and what the tradeoffs were.

graphql.go

@@ -18,6 +18,7 @@ import (
 	"github.com/graph-gophers/graphql-go/introspection"
 	"github.com/graph-gophers/graphql-go/log"
 	"github.com/graph-gophers/graphql-go/trace"
+	"github.com/graph-gophers/graphql-go/types"
 )
 
 // ParseSchema parses a GraphQL schema and attaches the given root resolver. It returns an error if
@@ -42,7 +43,7 @@ func ParseSchema(schemaString string, resolver interface{}, opts ...SchemaOpt) (
 		}
 	}
 
-	if err := s.schema.Parse(schemaString, s.useStringDescriptions); err != nil {
+	if err := schema.Parse(s.schema, schemaString, s.useStringDescriptions); err != nil {
 		return nil, err
 	}
 	if err := s.validateSchema(); err != nil {
@@ -69,7 +70,7 @@ func MustParseSchema(schemaString string, resolver interface{}, opts ...SchemaOp
 
 // Schema represents a GraphQL schema with an optional resolver.
 type Schema struct {
-	schema *schema.Schema
+	schema *types.Schema
 	res    *resolvable.Schema
 
 	maxDepth                 int
@@ -228,7 +229,7 @@ func (s *Schema) exec(ctx context.Context, queryString string, operationName str
 	}
 	for _, v := range op.Vars {
 		if _, ok := variables[v.Name.Name]; !ok && v.Default != nil {
-			variables[v.Name.Name] = v.Default.Value(nil)
+			variables[v.Name.Name] = v.Default.Deserialize(nil)
 		}
 	}
 
@@ -288,7 +289,7 @@ func (t *validationBridgingTracer) TraceValidation(context.Context) trace.TraceV
 	return t.tracer.TraceValidation()
 }
 
-func validateRootOp(s *schema.Schema, name string, mandatory bool) error {
+func validateRootOp(s *types.Schema, name string, mandatory bool) error {
 	t, ok := s.EntryPoints[name]
 	if !ok {
 		if mandatory {
@@ -302,7 +303,7 @@ func validateRootOp(s *schema.Schema, name string, mandatory bool) error {
 	return nil
 }
 
-func getOperation(document *query.Document, operationName string) (*query.Operation, error) {
+func getOperation(document *types.ExecutableDefinition, operationName string) (*types.OperationDefinition, error) {
 	if len(document.Operations) == 0 {
 		return nil, fmt.Errorf("no operations in query document")
 	}

internal/common/directive.go

@@ -1,32 +1,18 @@
 package common
 
-type Directive struct {
-	Name Ident
-	Args ArgumentList
-}
+import "github.com/graph-gophers/graphql-go/types"
 
-func ParseDirectives(l *Lexer) DirectiveList {
-	var directives DirectiveList
+func ParseDirectives(l *Lexer) types.DirectiveList {
+	var directives types.DirectiveList
 	for l.Peek() == '@' {
 		l.ConsumeToken('@')
-		d := &Directive{}
+		d := &types.Directive{}
 		d.Name = l.ConsumeIdentWithLoc()
 		d.Name.Loc.Column--
 		if l.Peek() == '(' {
-			d.Args = ParseArguments(l)
+			d.Arguments = ParseArgumentList(l)
 		}
 		directives = append(directives, d)
 	}
 	return directives
 }
-
-type DirectiveList []*Directive
-
-func (l DirectiveList) Get(name string) *Directive {
-	for _, d := range l {
-		if d.Name.Name == name {
-			return d
-		}
-	}
-	return nil
-}

internal/common/lexer.go

@@ -8,6 +8,7 @@ import (
 	"text/scanner"
 
 	"github.com/graph-gophers/graphql-go/errors"
+	"github.com/graph-gophers/graphql-go/types"
 )
 
 type syntaxError string
@@ -30,7 +31,6 @@ func NewLexer(s string, useStringDescriptions bool) *Lexer {
 	}
 	sc.Init(strings.NewReader(s))
 
-
 	l := Lexer{sc: sc, useStringDescriptions: useStringDescriptions}
 	l.sc.Error = l.CatchScannerError
 
@@ -119,11 +119,11 @@ func (l *Lexer) ConsumeIdent() string {
 	return name
 }
 
-func (l *Lexer) ConsumeIdentWithLoc() Ident {
+func (l *Lexer) ConsumeIdentWithLoc() types.Ident {
 	loc := l.Location()
 	name := l.sc.TokenText()
 	l.ConsumeToken(scanner.Ident)
-	return Ident{name, loc}
+	return types.Ident{name, loc}
 }
 
 func (l *Lexer) ConsumeKeyword(keyword string) {
@@ -133,8 +133,8 @@ func (l *Lexer) ConsumeKeyword(keyword string) {
 	l.ConsumeWhitespace()
 }
 
-func (l *Lexer) ConsumeLiteral() *BasicLit {
-	lit := &BasicLit{Type: l.next, Text: l.sc.TokenText()}
+func (l *Lexer) ConsumeLiteral() *types.PrimitiveValue {
+	lit := &types.PrimitiveValue{Type: l.next, Text: l.sc.TokenText()}
 	l.ConsumeWhitespace()
 	return lit
 }

internal/common/literals.go

@@ -1,160 +1,12 @@
 package common
 
 import (
-	"strconv"
-	"strings"
 	"text/scanner"
 
-	"github.com/graph-gophers/graphql-go/errors"
+	"github.com/graph-gophers/graphql-go/types"
 )
 
-type Literal interface {
-	Value(vars map[string]interface{}) interface{}
-	String() string
-	Location() errors.Location
-}
-
-type BasicLit struct {
-	Type rune
-	Text string
-	Loc  errors.Location
-}
-
-func (lit *BasicLit) Value(vars map[string]interface{}) interface{} {
-	switch lit.Type {
-	case scanner.Int:
-		value, err := strconv.ParseInt(lit.Text, 10, 32)
-		if err != nil {
-			panic(err)
-		}
-		return int32(value)
-
-	case scanner.Float:
-		value, err := strconv.ParseFloat(lit.Text, 64)
-		if err != nil {
-			panic(err)
-		}
-		return value
-
-	case scanner.String:
-		value, err := strconv.Unquote(lit.Text)
-		if err != nil {
-			panic(err)
-		}
-		return value
-
-	case scanner.Ident:
-		switch lit.Text {
-		case "true":
-			return true
-		case "false":
-			return false
-		default:
-			return lit.Text
-		}
-
-	default:
-		panic("invalid literal")
-	}
-}
-
-func (lit *BasicLit) String() string {
-	return lit.Text
-}
-
-func (lit *BasicLit) Location() errors.Location {
-	return lit.Loc
-}
-
-type ListLit struct {
-	Entries []Literal
-	Loc     errors.Location
-}
-
-func (lit *ListLit) Value(vars map[string]interface{}) interface{} {
-	entries := make([]interface{}, len(lit.Entries))
-	for i, entry := range lit.Entries {
-		entries[i] = entry.Value(vars)
-	}
-	return entries
-}
-
-func (lit *ListLit) String() string {
-	entries := make([]string, len(lit.Entries))
-	for i, entry := range lit.Entries {
-		entries[i] = entry.String()
-	}
-	return "[" + strings.Join(entries, ", ") + "]"
-}
-
-func (lit *ListLit) Location() errors.Location {
-	return lit.Loc
-}
-
-type ObjectLit struct {
-	Fields []*ObjectLitField
-	Loc    errors.Location
-}
-
-type ObjectLitField struct {
-	Name  Ident
-	Value Literal
-}
-
-func (lit *ObjectLit) Value(vars map[string]interface{}) interface{} {
-	fields := make(map[string]interface{}, len(lit.Fields))
-	for _, f := range lit.Fields {
-		fields[f.Name.Name] = f.Value.Value(vars)
-	}
-	return fields
-}
-
-func (lit *ObjectLit) String() string {
-	entries := make([]string, 0, len(lit.Fields))
-	for _, f := range lit.Fields {
-		entries = append(entries, f.Name.Name+": "+f.Value.String())
-	}
-	return "{" + strings.Join(entries, ", ") + "}"
-}
-
-func (lit *ObjectLit) Location() errors.Location {
-	return lit.Loc
-}
-
-type NullLit struct {
-	Loc errors.Location
-}
-
-func (lit *NullLit) Value(vars map[string]interface{}) interface{} {
-	return nil
-}
-
-func (lit *NullLit) String() string {
-	return "null"
-}
-
-func (lit *NullLit) Location() errors.Location {
-	return lit.Loc
-}
-
-type Variable struct {
-	Name string
-	Loc  errors.Location
-}
-
-func (v Variable) Value(vars map[string]interface{}) interface{} {
-	return vars[v.Name]
-}
-
-func (v Variable) String() string {
-	return "$" + v.Name
-}
-
-func (v *Variable) Location() errors.Location {
-	return v.Loc
-}
-
-func ParseLiteral(l *Lexer, constOnly bool) Literal {
+func ParseLiteral(l *Lexer, constOnly bool) types.Value {
 	loc := l.Location()
 	switch l.Peek() {
 	case '$':
@@ -163,12 +15,12 @@ func ParseLiteral(l *Lexer, constOnly bool) Literal {
 			panic("unreachable")
 		}
 		l.ConsumeToken('$')
-		return &Variable{l.ConsumeIdent(), loc}
+		return &types.Variable{l.ConsumeIdent(), loc}
 
 	case scanner.Int, scanner.Float, scanner.String, scanner.Ident:
 		lit := l.ConsumeLiteral()
 		if lit.Type == scanner.Ident && lit.Text == "null" {
-			return &NullLit{loc}
+			return &types.NullValue{loc}
 		}
 		lit.Loc = loc
 		return lit
@@ -180,24 +32,24 @@ func ParseLiteral(l *Lexer, constOnly bool) Literal {
 		return lit
 	case '[':
 		l.ConsumeToken('[')
-		var list []Literal
+		var list []types.Value
 		for l.Peek() != ']' {
 			list = append(list, ParseLiteral(l, constOnly))
 		}
 		l.ConsumeToken(']')
-		return &ListLit{list, loc}
+		return &types.ListValue{list, loc}
 
 	case '{':
 		l.ConsumeToken('{')
-		var fields []*ObjectLitField
+		var fields []*types.ObjectField
 		for l.Peek() != '}' {
 			name := l.ConsumeIdentWithLoc()
 			l.ConsumeToken(':')
 			value := ParseLiteral(l, constOnly)
-			fields = append(fields, &ObjectLitField{name, value})
+			fields = append(fields, &types.ObjectField{name, value})
 		}
 		l.ConsumeToken('}')
-		return &ObjectLit{fields, loc}
+		return &types.ObjectValue{fields, loc}
 
 	default:
 		l.SyntaxError("invalid value")