RFC: Schema Coordinates

src/index.ts

@@ -223,6 +223,7 @@ export {
   parseValue,
   parseConstValue,
   parseType,
+  parseSchemaCoordinate,
   // Print
   print,
   // Visit
@@ -243,6 +244,7 @@ export {
   isTypeDefinitionNode,
   isTypeSystemExtensionNode,
   isTypeExtensionNode,
+  isSchemaCoordinateNode,
 } from './language/index.js';
 
 export type {
@@ -315,6 +317,7 @@ export type {
   UnionTypeExtensionNode,
   EnumTypeExtensionNode,
   InputObjectTypeExtensionNode,
+  SchemaCoordinateNode,
 } from './language/index.js';
 
 // Execute GraphQL queries.
@@ -482,6 +485,8 @@ export {
   findBreakingChanges,
   findDangerousChanges,
   findSchemaChanges,
+  resolveSchemaCoordinate,
+  resolveASTSchemaCoordinate,
 } from './utilities/index.js';
 
 export type {
@@ -512,4 +517,5 @@ export type {
   SafeChange,
   DangerousChange,
   TypedQueryDocumentNode,
+  ResolvedSchemaElement,
 } from './utilities/index.js';

src/language/__tests__/lexer-test.ts

@@ -165,13 +165,6 @@ describe('Lexer', () => {
     });
   });
 
-  it('reports unexpected characters', () => {
-    expectSyntaxError('.').to.deep.equal({
-      message: 'Syntax Error: Unexpected character: ".".',
-      locations: [{ line: 1, column: 1 }],
-    });
-  });
-
   it('errors respect whitespace', () => {
     let caughtError;
     try {
@@ -965,6 +958,13 @@ describe('Lexer', () => {
       value: undefined,
     });
 
+    expect(lexOne('.')).to.contain({
+      kind: TokenKind.DOT,
+      start: 0,
+      end: 1,
+      value: undefined,
+    });
+
     expect(lexOne('...')).to.contain({
       kind: TokenKind.SPREAD,
       start: 0,

src/language/__tests__/parser-test.ts

@@ -11,7 +11,13 @@ import { kitchenSinkQuery } from '../../__testUtils__/kitchenSinkQuery.js';
 import { inspect } from '../../jsutils/inspect.js';
 
 import { Kind } from '../kinds.js';
-import { parse, parseConstValue, parseType, parseValue } from '../parser.js';
+import {
+  parse,
+  parseConstValue,
+  parseSchemaCoordinate,
+  parseType,
+  parseValue,
+} from '../parser.js';
 import { Source } from '../source.js';
 import { TokenKind } from '../tokenKind.js';
 
@@ -679,4 +685,129 @@ describe('Parser', () => {
       });
     });
   });
+
+  describe('parseSchemaCoordinate', () => {
+    it('parses Name', () => {
+      const result = parseSchemaCoordinate('MyType');
+      expectJSON(result).toDeepEqual({
+        kind: Kind.SCHEMA_COORDINATE,
+        loc: { start: 0, end: 6 },
+        ofDirective: false,
+        name: {
+          kind: Kind.NAME,
+          loc: { start: 0, end: 6 },
+          value: 'MyType',
+        },
+        memberName: undefined,
+        argumentName: undefined,
+      });
+    });
+
+    it('parses Name . Name', () => {
+      const result = parseSchemaCoordinate('MyType.field');
+      expectJSON(result).toDeepEqual({
+        kind: Kind.SCHEMA_COORDINATE,
+        loc: { start: 0, end: 12 },
+        ofDirective: false,
+        name: {
+          kind: Kind.NAME,
+          loc: { start: 0, end: 6 },
+          value: 'MyType',
+        },
+        memberName: {
+          kind: Kind.NAME,
+          loc: { start: 7, end: 12 },
+          value: 'field',
+        },
+        argumentName: undefined,
+      });
+    });
+
+    it('rejects Name . Name . Name', () => {
+      expectToThrowJSON(() =>
+        parseSchemaCoordinate('MyType.field.deep'),
+      ).to.deep.equal({
+        message: 'Syntax Error: Expected <EOF>, found ".".',
+        locations: [{ line: 1, column: 13 }],
+      });
+    });
+
+    it('parses Name . Name ( Name : )', () => {
+      const result = parseSchemaCoordinate('MyType.field(arg:)');
+      expectJSON(result).toDeepEqual({
+        kind: Kind.SCHEMA_COORDINATE,
+        loc: { start: 0, end: 18 },
+        ofDirective: false,
+        name: {
+          kind: Kind.NAME,
+          loc: { start: 0, end: 6 },
+          value: 'MyType',
+        },
+        memberName: {
+          kind: Kind.NAME,
+          loc: { start: 7, end: 12 },
+          value: 'field',
+        },
+        argumentName: {
+          kind: Kind.NAME,
+          loc: { start: 13, end: 16 },
+          value: 'arg',
+        },
+      });
+    });
+
+    it('rejects Name . Name ( Name : Name )', () => {
+      expectToThrowJSON(() =>
+        parseSchemaCoordinate('MyType.field(arg: value)'),
+      ).to.deep.equal({
+        message: 'Syntax Error: Expected ")", found Name "value".',
+        locations: [{ line: 1, column: 19 }],
+      });
+    });
+
+    it('parses @ Name', () => {
+      const result = parseSchemaCoordinate('@myDirective');
+      expectJSON(result).toDeepEqual({
+        kind: Kind.SCHEMA_COORDINATE,
+        loc: { start: 0, end: 12 },
+        ofDirective: true,
+        name: {
+          kind: Kind.NAME,
+          loc: { start: 1, end: 12 },
+          value: 'myDirective',
+        },
+        memberName: undefined,
+        argumentName: undefined,
+      });
+    });
+
+    it('parses @ Name ( Name : )', () => {
+      const result = parseSchemaCoordinate('@myDirective(arg:)');
+      expectJSON(result).toDeepEqual({
+        kind: Kind.SCHEMA_COORDINATE,
+        loc: { start: 0, end: 18 },
+        ofDirective: true,
+        name: {
+          kind: Kind.NAME,
+          loc: { start: 1, end: 12 },
+          value: 'myDirective',
+        },
+        memberName: undefined,
+        argumentName: {
+          kind: Kind.NAME,
+          loc: { start: 13, end: 16 },
+          value: 'arg',
+        },
+      });
+    });
+
+    it('rejects @ Name . Name', () => {
+      expectToThrowJSON(() =>
+        parseSchemaCoordinate('@myDirective.field'),
+      ).to.deep.equal({
+        message: 'Syntax Error: Expected <EOF>, found ".".',
+        locations: [{ line: 1, column: 13 }],
+      });
+    });
+  });
 });

src/language/__tests__/predicates-test.ts

@@ -8,6 +8,7 @@ import {
   isConstValueNode,
   isDefinitionNode,
   isExecutableDefinitionNode,
+  isSchemaCoordinateNode,
   isSelectionNode,
   isTypeDefinitionNode,
   isTypeExtensionNode,
@@ -141,4 +142,10 @@ describe('AST node predicates', () => {
       'InputObjectTypeExtension',
     ]);
   });
+
+  it('isSchemaCoordinateNode', () => {
+    expect(filterNodes(isSchemaCoordinateNode)).to.deep.equal([
+      'SchemaCoordinate',
+    ]);
+  });
 });

src/language/__tests__/printer-test.ts

@@ -5,7 +5,7 @@ import { dedent, dedentString } from '../../__testUtils__/dedent.js';
 import { kitchenSinkQuery } from '../../__testUtils__/kitchenSinkQuery.js';
 
 import { Kind } from '../kinds.js';
-import { parse } from '../parser.js';
+import { parse, parseSchemaCoordinate } from '../parser.js';
 import { print } from '../printer.js';
 
 describe('Printer: Query document', () => {
@@ -299,4 +299,18 @@ describe('Printer: Query document', () => {
     `),
     );
   });
+
+  it('prints schema coordinates', () => {
+    expect(print(parseSchemaCoordinate('  Name  '))).to.equal('Name');
+    expect(print(parseSchemaCoordinate('  Name . field '))).to.equal(
+      'Name.field',
+    );
+    expect(print(parseSchemaCoordinate('  Name . field ( arg: )'))).to.equal(
+      'Name.field(arg:)',
+    );
+    expect(print(parseSchemaCoordinate(' @ name  '))).to.equal('@name');
+    expect(print(parseSchemaCoordinate(' @ name (arg:) '))).to.equal(
+      '@name(arg:)',
+    );
+  });
 });

src/language/ast.ts

@@ -181,7 +181,8 @@ export type ASTNode =
   | InterfaceTypeExtensionNode
   | UnionTypeExtensionNode
   | EnumTypeExtensionNode
-  | InputObjectTypeExtensionNode;
+  | InputObjectTypeExtensionNode
+  | SchemaCoordinateNode;
 
 /**
  * Utility type listing all nodes indexed by their kind.
@@ -287,6 +288,8 @@ export const QueryDocumentKeys: {
   UnionTypeExtension: ['name', 'directives', 'types'],
   EnumTypeExtension: ['name', 'directives', 'values'],
   InputObjectTypeExtension: ['name', 'directives', 'fields'],
+
+  SchemaCoordinate: ['name', 'memberName', 'argumentName'],
 };
 
 const kindValues = new Set<string>(Object.keys(QueryDocumentKeys));
@@ -762,3 +765,14 @@ export interface InputObjectTypeExtensionNode {
   readonly directives?: ReadonlyArray<ConstDirectiveNode> | undefined;
   readonly fields?: ReadonlyArray<InputValueDefinitionNode> | undefined;
 }
+
+/** Schema Coordinates */
+
+export interface SchemaCoordinateNode {
+  readonly kind: typeof Kind.SCHEMA_COORDINATE;
+  readonly loc?: Location | undefined;
+  readonly ofDirective: boolean;
+  readonly name: NameNode;
+  readonly memberName?: NameNode | undefined;
+  readonly argumentName?: NameNode | undefined;
+}

src/language/index.ts

@@ -11,7 +11,13 @@ export { TokenKind } from './tokenKind.js';
 
 export { Lexer } from './lexer.js';
 
-export { parse, parseValue, parseConstValue, parseType } from './parser.js';
+export {
+  parse,
+  parseValue,
+  parseConstValue,
+  parseType,
+  parseSchemaCoordinate,
+} from './parser.js';
 export type { ParseOptions } from './parser.js';
 
 export { print } from './printer.js';
@@ -88,6 +94,7 @@ export type {
   UnionTypeExtensionNode,
   EnumTypeExtensionNode,
   InputObjectTypeExtensionNode,
+  SchemaCoordinateNode,
 } from './ast.js';
 
 export {
@@ -101,6 +108,7 @@ export {
   isTypeDefinitionNode,
   isTypeSystemExtensionNode,
   isTypeExtensionNode,
+  isSchemaCoordinateNode,
 } from './predicates.js';
 
 export { DirectiveLocation } from './directiveLocation.js';

src/language/kinds.ts

@@ -67,6 +67,9 @@ export const Kind = {
   UNION_TYPE_EXTENSION: 'UnionTypeExtension' as const,
   ENUM_TYPE_EXTENSION: 'EnumTypeExtension' as const,
   INPUT_OBJECT_TYPE_EXTENSION: 'InputObjectTypeExtension' as const,
+
+  /** Schema Coordinates */
+  SCHEMA_COORDINATE: 'SchemaCoordinate' as const,
 };
 // eslint-disable-next-line @typescript-eslint/no-redeclare
 export type Kind = (typeof Kind)[keyof typeof Kind];