changed try to testing for an empty list for legibility (as suggested by paultag), also added to authors

AUTHORS

@@ -13,3 +13,4 @@
 * rogererens <roger.erens@e-s-c.biz>
 * Thomas Ballinger <thomasballinger@gmail.com>
 * Morten Linderud <mcfoxax@gmail.com>
+* Guillermo Vayá <guivaya@gmail.com>

hy/macros.py

@@ -70,12 +70,13 @@ _wrappers = {
 
 def process(tree, module_name):
     if isinstance(tree, HyExpression):
-        try:
-            fn = tree[0]
-        except IndexError:
+        if tree == []:
+            # set value to []
             ntree = HyList()
             ntree.replace(tree)
             return ntree
+        
+        fn = tree[0]
         if fn in ("quote", "quasiquote"):
             return tree
         ntree = HyExpression(