added changes to accept spairs; merged #58

.test/tests.lua

@@ -6,7 +6,6 @@ package.path = package.path .. ";../?.lua"
 local assert = require("batteries.assert")
 local tablex = require("batteries.tablex")
 
-
 -- tablex {{{
 
 local function test_shallow_copy()
@@ -59,7 +58,9 @@ local function test_shallow_overlay()
 	assert(
 		tablex.deep_equal(
 			r,
-			{ b = { 2 }, c = { 8 }, d = { 9 }, }))
+			{ b = { 2 }, c = { 8 }, d = { 9 }, }
+		)
+	)
 end
 
 local function test_deep_overlay()
@@ -70,7 +71,9 @@ local function test_deep_overlay()
 	assert(
 		tablex.deep_equal(
 			r,
-			{ a = 1, b = 2, c = 8, d = 9 }))
+			{ a = 1, b = 2, c = 8, d = 9 }
+		)
+	)
 
 	x = { a = { b = { 2 }, c = { 3 }, } }
 	y = { a = { c = { 8 }, d = { 9 }, } }
@@ -78,7 +81,9 @@ local function test_deep_overlay()
 	assert(
 		tablex.deep_equal(
 			r,
-			{ a = { b = { 2 }, c = { 8 }, d = { 9 }, } }))
+			{ a = { b = { 2 }, c = { 8 }, d = { 9 }, } }
+		)
+	)
 end
 
 
@@ -135,20 +140,18 @@ local function test_spairs()
 	local sorted_names = {}
 	local sorted_score = {}
 	
-	for k, v in tablex.spairs(t, function(t, a, b)
+	for k, v in tablex.spairs(t, function(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,
-	{
+	assert(tablex.deep_equal(sorted_names, {
 		"John", "Joe", "Robert"
 	}))
 	
-	assert(tablex.deep_equal(sorted_score,
-	{
+	assert(tablex.deep_equal(sorted_score, {
 		10, 8, 7
 	}))
 end

sort.lua

@@ -97,7 +97,16 @@ function sort._merge_sort_impl(array, workspace, low, high, less)
 end
 
 --default comparison; hoisted for clarity
+local _sorted_types = {
+	--a list of types that will be sorted by default_less
+	--provide a custom sort function to sort other types
+	["string"] = true,
+	["number"] = true,
+}
 local function default_less(a, b)
+	if not _sorted_types[type(a)] or not _sorted_types[type(b)] then
+		return false
+	end
 	return a < b
 end
 

tablex.lua

@@ -2,13 +2,17 @@
 	extra table routines
 ]]
 
---apply prototype to module if it isn't the global table
---so it works "as if" it was the global table api
---upgraded with these routines
-
 local path = (...):gsub("tablex", "")
 local assert = require(path .. "assert")
 
+--for spairs
+--(can be replaced with eg table.sort to use that instead)
+local sort = require(path .. "sort")
+local spairs_sort = sort.stable_sort
+
+--apply prototype to module if it isn't the global table
+--so it works "as if" it was the global table api
+--upgraded with these routines
 local tablex = setmetatable({}, {
 	__index = table,
 })
@@ -78,11 +82,8 @@ function tablex.rotate(t, amount)
 	return t
 end
 
---default comparison; hoisted for clarity
---(shared with sort.lua and suggests the sorted functions below should maybe be refactored there)
-local function default_less(a, b)
-	return a < b
-end
+--default comparison from sort.lua
+local default_less = sort.default_less
 
 --check if a function is sorted based on a "less" or "comes before" ordering comparison
 --if any item is "less" than the item before it, we are not sorted
@@ -538,18 +539,15 @@ function tablex.ripairs(t)
 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
+--	generates a fair bit of garbage but very nice for more stable output
+--	less function gets keys the of the table as its argument; if you want to sort on the values they map to then
+--		you'll likely need a closure
+function tablex.spairs(t, less)
+	less = less or default_less
+	--gather the keys
+	local keys = tablex.keys(t)
 
-	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
+	spairs_sort(keys, less)
 
 	local i = 0
 	return function()