From 3f87977ddb135a709b9b86eb491aacfdef2cbdf0 Mon Sep 17 00:00:00 2001
From: Kim Alvefur <zash@zash.se>
Date: Fri, 15 Apr 2016 13:20:31 +0200
Subject: util.iterators: Add iterator wrapper that works like select(n, ...)
 applied to original iterator

---
 util/iterators.lua | 9 +++++++++
 1 file changed, 9 insertions(+)

(limited to 'util')

diff --git a/util/iterators.lua b/util/iterators.lua
index 5f03bd10..bd150ff2 100644
--- a/util/iterators.lua
+++ b/util/iterators.lua
@@ -54,6 +54,15 @@ function it.values(t)
 	end, t;
 end
 
+-- Iterate over the n:th return value
+function it.select(n, f, s, var)
+	return function (_s)
+		local ret = pack(f(_s, var));
+		var = ret[1];
+		return ret[n];
+	end, s, var;
+end
+
 -- Given an iterator, iterate only over unique items
 function it.unique(f, s, var)
 	local set = {};
-- 
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