From edd7c99382fe1bf686cbd750db62bcb47c6294b6 Mon Sep 17 00:00:00 2001
From: rxi <rxi@users.noreply.github.com>
Date: Sun, 11 Jan 2015 14:58:12 +0000
Subject: [PATCH] Added lume.ripairs() function, updated README and tests

---
 README.md          | 11 +++++++++++
 lume.lua           | 14 ++++++++++++++
 test/test_lume.lua | 12 ++++++++++++
 3 files changed, 37 insertions(+)

diff --git a/README.md b/README.md
index 281f476..0c4f65e 100644
--- a/README.md
+++ b/README.md
@@ -361,6 +361,17 @@ lume.hotswap("lume") -- Reloads the lume module
 assert(lume.hotswap("inexistant_module")) -- Raises an error
 ```
 
+### lume.ripairs(t)
+Performs the same function as `ipairs()` but iterates in reverse; this allows
+the removal of items from the table during iteration without any items being
+skipped.
+```lua
+-- Prints "3->c", "2->b" and "1->a" on separate lines
+for i, v in lume.ripairs({ "a", "b", "c" }) do
+  print(i .. "->" .. v)
+end
+```
+
 ### lume.rgba(color)
 Takes the 32bit integer `color` argument and returns 4 numbers, one for each
 channel, with a range of 0 - 255. The returned values can be used as the
diff --git a/lume.lua b/lume.lua
index 5813492..54e8eec 100644
--- a/lume.lua
+++ b/lume.lua
@@ -578,6 +578,20 @@ function lume.hotswap(modname)
 end
 
 
+local ripairs_iter = function(t, i)
+  i = i - 1
+  local v = t[i]
+  if v then return i, v end
+end
+
+function lume.ripairs(t)
+  if t == nil then
+    return noop
+  end
+  return ripairs_iter, t, (#t + 1)
+end
+
+
 function lume.rgba(color)
   local a = math_floor((color / 16777216) % 256)
   local r = math_floor((color /    65536) % 256)
diff --git a/test/test_lume.lua b/test/test_lume.lua
index 805351e..735f908 100644
--- a/test/test_lume.lua
+++ b/test/test_lume.lua
@@ -486,6 +486,18 @@ tests["lume.hotswap"] = function()
   testeq( type(err),  "string"  )
 end
 
+-- lume.ripairs
+tests["lume.ripairs"] = function()
+  local t = { "a", "b", "c" }
+  local r = {}
+  for i, v in lume.ripairs(t) do
+    table.insert(r, { i, v })
+  end
+  testeq( r, { { 3, "c" }, { 2, "b" }, { 1, "a" } })
+  for i, v in lume.ripairs(nil) do
+  end
+end
+
 -- lume.rgba
 tests["lume.rgba"] = function()
   local r, g, b, a = lume.rgba(0x12345678)