tablex: Add spairs (alternative of pairs that returns sorted table)

.test/tests.lua

@@ -116,3 +116,39 @@ local function test_deep_equal()
 	assert(not tablex.deep_equal(y, x))
 end
 
+local function test_spairs()
+	local t = {
+		player1 = {
+			name = "Joe",
+			score = 8
+		},
+		player2 = {
+			name = "Robert",
+			score = 7
+		},
+		player3 = {
+			name = "John",
+			score = 10
+		}
+	}
+	
+	local sorted_names = {}
+	local sorted_score = {}
+	
+	for k, v in tablex.spairs(t, function(t, a, b)
+		return t[a].score > t[b].score
+	end) do
+		tablex.push(sorted_names, v.name)
+		tablex.push(sorted_score, v.score)
+	end
+	
+	assert(tablex.deep_equal(sorted_names,
+	{
+		"John", "Joe", "Robert"
+	}))
+	
+	assert(tablex.deep_equal(sorted_score,
+	{
+		10, 8, 7
+	}))
+end

tablex.lua

@@ -537,4 +537,28 @@ function tablex.ripairs(t)
 	return _ripairs_iter, t, #t + 1
 end
 
+-- works like pairs, but returns sorted table
+function tablex.spairs(t, fn)
+	local keys = {}
+	for k in pairs(t) do
+		tablex.push(keys, k)
+	end
+
+	if fn then
+		table.sort(keys, function(a,b) return fn(t, a, b) end)
+	else
+		-- sort by keys if no function passed
+		table.sort(keys)
+	end
+
+	local i = 0
+	return function()
+		i = i + 1
+		if keys[i] then
+			return keys[i], t[keys[i]]
+		end
+	end
+end
+
+
 return tablex