From 366ee57b2aa6428b2bf823fd044a9d5685a716cc Mon Sep 17 00:00:00 2001
From: Leandro Facchinetti <me@leafac.com>
Date: Thu, 14 Apr 2016 07:21:07 -0400
Subject: [PATCH] Fix `dot notation for nested hash lookups' example

The previous snippet had a guard of "fender" clause that always resulted in an error, even on valid calls. The fixed snippet performs a check and only errors in bad cases.
---
 index.rkt | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/index.rkt b/index.rkt
index dcc7dd3..2060e6d 100644
--- a/index.rkt
+++ b/index.rkt
@@ -1212,7 +1212,8 @@ messages when used in error. Let's try to do that here.
     [(_ chain)
      #'(hash.refs chain #f)]
     [(_ chain default)
-     (raise-syntax-error #f "Expected hash.key0[.key1 ...] [default]" stx #'chain)
+     (unless (identifier? #'chain)
+       (raise-syntax-error #f "Expected hash.key0[.key1 ...] [default]" stx #'chain))
      (let* ([chain-str (symbol->string (syntax->datum #'chain))]
             [ids (for/list ([str (in-list (regexp-split #rx"\\." chain-str))])
                    (format-id #'chain "~a" str))])