Replace = with as

Author: leebyron

src/language/__tests__/schema-kitchen-sink.graphql

@@ -65,10 +65,10 @@ extend union Feed @onUnion
 
 scalar CustomScalar
 
-scalar StringEncodedCustomScalar = String
-
 scalar AnnotatedScalar @onScalar
 
+scalar StringEncodedCustomScalar as String
+
 extend scalar CustomScalar @onScalar
 
 enum Site {

src/language/__tests__/schema-printer-test.js

@@ -111,9 +111,7 @@ describe('Printer', () => {
 
       scalar AnnotatedScalar @onScalar
 
-      scalar StringEncodedCustomScalar = String
-
-      scalar AnnotatedScalar @onScalar
+      scalar StringEncodedCustomScalar as String
 
       extend scalar CustomScalar @onScalar
 

src/language/parser.js

@@ -893,14 +893,17 @@ function parseOperationTypeDefinition(
  * ScalarTypeDefinition :
  *   - Description? scalar Name ScalarOfType? Directives[Const]?
  *
- * ScalarOfType : = NamedType
+ * ScalarOfType : as NamedType
  */
 function parseScalarTypeDefinition(lexer: Lexer<*>): ScalarTypeDefinitionNode {
   const start = lexer.token;
   const description = parseDescription(lexer);
   expectKeyword(lexer, 'scalar');
   const name = parseName(lexer);
-  const type = skip(lexer, TokenKind.EQUALS) ? parseNamedType(lexer) : null;
+  let type;
+  if (skipKeyword(lexer, 'as')) {
+    type = parseNamedType(lexer);
+  }
   const directives = parseDirectives(lexer, true);
   return {
     kind: SCALAR_TYPE_DEFINITION,
@@ -1508,10 +1511,24 @@ function expect(lexer: Lexer<*>, kind: string): Token {
 }
 
 /**
- * If the next token is a keyword with the given value, return that token after
+ * If the next token is a keyword with the given value, return true after
  * advancing the lexer. Otherwise, do not change the parser state and return
  * false.
  */
+function skipKeyword(lexer: Lexer<*>, value: string): boolean {
+  const token = lexer.token;
+  const match = token.kind === TokenKind.NAME && token.value === value;
+  if (match) {
+    lexer.advance();
+  }
+  return match;
+}
+
+/**
+ * If the next token is a keyword with the given value, return that token after
+ * advancing the lexer. Otherwise, do not change the parser state and throw
+ * an error.
+ */
 function expectKeyword(lexer: Lexer<*>, value: string): Token {
   const token = lexer.token;
   if (token.kind === TokenKind.NAME && token.value === value) {

src/language/printer.js

@@ -112,7 +112,7 @@ const printDocASTReducer = {
 
   ScalarTypeDefinition: ({ description, name, directives }) =>
     join(
-      [description, join(['scalar', name, wrap(' = ', type), join(directives, ' ')], ' ')],
+      [description, join(['scalar', name, wrap(' as ', type), join(directives, ' ')], ' ')],
       '\n',
     ),
 

src/type/__tests__/introspection-test.js

@@ -1307,7 +1307,9 @@ describe('Introspection', () => {
             'An enum describing what kind of type a given `__Type` is.',
           enumValues: [
             {
-              description: 'Indicates this type is a scalar. `ofType` is a valid field.',
+              description:
+                'Indicates this type is a scalar. ' +
+                '`ofType` may represent how this scalar is serialized.',
               name: 'SCALAR'
             },
             {

src/type/introspection.js

@@ -207,8 +207,8 @@ export const __Type = new GraphQLObjectType({
     'The fundamental unit of any GraphQL Schema is the type. There are ' +
     'many kinds of types in GraphQL as represented by the `__TypeKind` enum.' +
     '\n\nDepending on the kind of a type, certain fields describe ' +
-    'information about that type. Scalar types provide no information ' +
-    'beyond a name and description, while Enum types provide their values. ' +
+    'information about that type. Scalar types provide a name, description' +
+    'and how they serialize, while Enum types provide their possible values. ' +
     'Object and Interface types provide the fields they describe. Abstract ' +
     'types, Union and Interface, provide the Object types possible ' +
     'at runtime. List and NonNull types compose other types.',
@@ -381,7 +381,9 @@ export const __TypeKind = new GraphQLEnumType({
   values: {
     SCALAR: {
       value: TypeKind.SCALAR,
-      description: 'Indicates this type is a scalar. `ofType` is a valid field.',
+      description:
+        'Indicates this type is a scalar. ' +
+        '`ofType` may represent how this scalar is serialized.',
     },
     OBJECT: {
       value: TypeKind.OBJECT,

src/utilities/__tests__/schemaPrinter-test.js

@@ -529,25 +529,15 @@ describe('Type System Printer', () => {
         query: Root
       }
 
-<<<<<<< HEAD
+      scalar Even as Int
+
       scalar Odd
 
       type Root {
+        even: Even
         odd: Odd
       }
     `);
-=======
-scalar Even = Int
-
-scalar Odd
-
-type Root {
-  even: Even
-  odd: Odd
-}
-`
-     );
->>>>>>> RFC: Define custom scalars in terms of built-in scalars.
   });
 
   it('Enum', () => {
@@ -1023,10 +1013,10 @@ type Root {
       # types in GraphQL as represented by the \`__TypeKind\` enum.
       #
       # Depending on the kind of a type, certain fields describe information about that
-      # type. Scalar types provide no information beyond a name and description, while
-      # Enum types provide their values. Object and Interface types provide the fields
-      # they describe. Abstract types, Union and Interface, provide the Object types
-      # possible at runtime. List and NonNull types compose other types.
+      # type. Scalar types provide a name, descriptionand how they serialize, while Enum
+      # types provide their possible values. Object and Interface types provide the
+      # fields they describe. Abstract types, Union and Interface, provide the Object
+      # types possible at runtime. List and NonNull types compose other types.
       type __Type {
         kind: __TypeKind!
         name: String
@@ -1041,7 +1031,7 @@ type Root {
 
       # An enum describing what kind of type a given \`__Type\` is.
       enum __TypeKind {
-        # Indicates this type is a scalar. \`ofType\` is a valid field.
+        # Indicates this type is a scalar. \`ofType\` may represent how this scalar is serialized.
         SCALAR
 
         # Indicates this type is an object. \`fields\` and \`interfaces\` are valid fields.

src/utilities/schemaPrinter.js

@@ -170,7 +170,7 @@ export function printType(type: GraphQLNamedType, options?: Options): string {
 }
 
 function printScalar(type: GraphQLScalarType, options): string {
-  const ofType = type.ofType ? ` = ${type.ofType.name}` : '';
+  const ofType = type.ofType ? ` as ${type.ofType.name}` : '';
   return printDescription(options, type) + `scalar ${type.name}${ofType}`;
 }