# HG changeset patch
# User Kim Alvefur <zash@zash.se>
# Date 1460719231 -7200
# Node ID 4b4cf01673918ea3370d5241e8d06e6242a3643f
# Parent  8ca7f1c2c660e87937a2ea6c61c5308e165f5f08
util.iterators: Add iterator wrapper that works like select(n, ...) applied to original iterator

diff -r 8ca7f1c2c660 -r 4b4cf0167391 util/iterators.lua
--- a/util/iterators.lua	Fri Apr 15 13:19:20 2016 +0200
+++ b/util/iterators.lua	Fri Apr 15 13:20:31 2016 +0200
@@ -54,6 +54,15 @@
 	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 = {};