From 7de0c0cb69488d416d7483aaa81d9be0ab35a283 Mon Sep 17 00:00:00 2001
From: Doug Coleman <doug.coleman@gmail.com>
Date: Fri, 24 Aug 2012 15:00:33 -0700
Subject: [PATCH] hashtables: Enforce shape on hashtable literals. Fixes #568.

---
 core/hashtables/hashtables.factor | 8 ++++++++
 core/syntax/syntax.factor         | 2 +-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/core/hashtables/hashtables.factor b/core/hashtables/hashtables.factor
index d6fa375dd2..ee1fcdefa7 100644
--- a/core/hashtables/hashtables.factor
+++ b/core/hashtables/hashtables.factor
@@ -181,4 +181,12 @@ M: hashtable assoc-like
     [ hashcode 0x13c6ef37 + ] dip
     [ 6 shift ] [ -2 shift ] bi + + ;
 
+ERROR: malformed-hashtable-pair seq pair ;
+
+: check-hashtable ( seq -- seq )
+    dup [ dup length 2 = [ drop ] [ malformed-hashtable-pair ] if ] each ;
+
+: parse-hashtable ( seq -- hashtable )
+    check-hashtable H{ } assoc-clone-like ;
+
 INSTANCE: hashtable assoc
diff --git a/core/syntax/syntax.factor b/core/syntax/syntax.factor
index e356f8d88e..441a4dfb7d 100644
--- a/core/syntax/syntax.factor
+++ b/core/syntax/syntax.factor
@@ -97,7 +97,7 @@ IN: bootstrap.syntax
     "V{" [ \ } [ >vector ] parse-literal ] define-core-syntax
     "B{" [ \ } [ >byte-array ] parse-literal ] define-core-syntax
     "BV{" [ \ } [ >byte-vector ] parse-literal ] define-core-syntax
-    "H{" [ \ } [ >hashtable ] parse-literal ] define-core-syntax
+    "H{" [ \ } [ parse-hashtable ] parse-literal ] define-core-syntax
     "T{" [ parse-tuple-literal suffix! ] define-core-syntax
     "W{" [ \ } [ first <wrapper> ] parse-literal ] define-core-syntax
     "HS{" [ \ } [ >hash-set ] parse-literal ] define-core-syntax