Fix infinite recursion in type definition parser

Fixes #637.

Author: Invizory

language/parser/parser.go

@@ -19,12 +19,6 @@ var tokenDefinitionFn map[string]parseDefinitionFn
 func init() {
 	tokenDefinitionFn = make(map[string]parseDefinitionFn)
 	{
-		// for sign
-		tokenDefinitionFn[lexer.BRACE_L.String()] = parseOperationDefinition
-		tokenDefinitionFn[lexer.STRING.String()] = parseTypeSystemDefinition
-		tokenDefinitionFn[lexer.BLOCK_STRING.String()] = parseTypeSystemDefinition
-		tokenDefinitionFn[lexer.NAME.String()] = parseTypeSystemDefinition
-		// for NAME
 		tokenDefinitionFn[lexer.FRAGMENT] = parseFragmentDefinition
 		tokenDefinitionFn[lexer.QUERY] = parseOperationDefinition
 		tokenDefinitionFn[lexer.MUTATION] = parseOperationDefinition
@@ -145,8 +139,10 @@ func parseDocument(parser *Parser) (*ast.Document, error) {
 			break
 		}
 		switch kind := parser.Token.Kind; kind {
-		case lexer.BRACE_L, lexer.NAME, lexer.STRING, lexer.BLOCK_STRING:
-			item = tokenDefinitionFn[kind.String()]
+		case lexer.BRACE_L:
+			item = parseOperationDefinition
+		case lexer.NAME, lexer.STRING, lexer.BLOCK_STRING:
+			item = parseTypeSystemDefinition
 		default:
 			return nil, unexpected(parser, lexer.Token{})
 		}

language/parser/parser_test.go

@@ -736,6 +736,15 @@ func TestParseCreatesAst(t *testing.T) {
 
 }
 
+func TestDoesNotAcceptStringAsDefinition(t *testing.T) {
+	test := errorMessageTest{
+		`String`,
+		`Syntax Error GraphQL (1:1) Unexpected Name "String"`,
+		false,
+	}
+	testErrorMessage(t, test)
+}
+
 type errorMessageTest struct {
 	source          interface{}
 	expectedMessage string