From a41a3c7edc647d7d9bcb64913c03fae22ef71345 Mon Sep 17 00:00:00 2001
From: Abhishek L <abhishek.lekshmanan@gmail.com>
Date: Tue, 4 Feb 2014 01:35:41 +0530
Subject: [PATCH] faster distinct: maintain seen items in a set

* hy/core/language.hy: maintain the seen items in a set instead of a
  list in `distinct`. This is much faster for lookups.
---
 hy/core/language.hy | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hy/core/language.hy b/hy/core/language.hy
index 520d3f1..7fd5b2a 100644
--- a/hy/core/language.hy
+++ b/hy/core/language.hy
@@ -75,12 +75,12 @@
 (defn distinct [coll]
   "Return a generator from the original collection with duplicates
    removed"
-  (let [[seen []] [citer (iter coll)]]
+  (let [[seen (set)] [citer (iter coll)]]
     (for* [val citer]
       (if (not_in val seen)
         (do
          (yield val)
-         (.append seen val))))))
+         (.add seen val))))))
 
 (defn drop [count coll]
   "Drop `count` elements from `coll` and yield back the rest"