start writing results back to disk

I make some effort to preserve order, but deleting results and then
readding them appends to the bottom.

0003-draw_data

@@ -84,13 +84,18 @@ draw_data = function()
 							return
 						elseif v == nil then
 							Data[t1][t2] = 2 Data[t2][t1] = 0
+							add_result(t1, t2)
 						elseif v == 2 then
 							Data[t1][t2] = 0 Data[t2][t1] = 2
+							delete_result(t1, t2)
+							add_result(t2, t1)
 						elseif v == 0 then
 							Data[t1][t2] = nil Data[t2][t1] = nil
+							delete_result(t2, t1)
 						else
 							error('invalid value')
 						end
+						Global_state.next_save = Current_time + 3
 					end,
 				})
 			end
@@ -101,4 +106,4 @@ draw_data = function()
 		App.color{r=0, g=0, b=0}
 		love.graphics.print(score(Data, t1), l+px, top+y*c+py)
 	end
-end
+end

0011-Global_state

@@ -1 +1,6 @@
-Global_state = {}  -- just anything we need across functions
+  -- just anything we need across functions
+Global_state = {
+	button_handlers = {},
+	next_save = nil,  -- if set, timestamp at which to save results to disk
+	results = {},  -- information about order in which to save to disk
+}

0020-load_results

@@ -1,9 +1,11 @@
 load_results = function(filename)
 	results = {}
+	Global_state.results = {}  -- cache ordering for when we modify Data
 	local f, err = App.open_for_reading(filename)
 	if err then error(err) end
 	for line in f:lines() do
 		local subject, object = line:match('^%s*(%S+)%s+beat%s+(%S+)%s*$')
+		table.insert(Global_state.results, {subject, object})
 		if subject == nil then
 			error('incorrect format: '..line)
 		end

0023-on.update

@@ -0,0 +1,6 @@
+on.update = function()
+	if Global_state.next_save and Global_state.next_save < Current_time then
+		save_results()
+		Global_state.next_save = nil
+	end
+end

0024-save_results

@@ -0,0 +1,10 @@
+save_results = function()
+	if Results_filename == nil then return end
+	print('saving to '..Results_filename)
+	local f, err = App.open_for_writing(Results_filename)
+	if err then error(err) end
+	for _,result in ipairs(Global_state.results) do
+		f:write(('%s beat %s\n'):format(result[1], result[2]))
+	end
+	f:close()
+end

0025-on.quit

@@ -0,0 +1,6 @@
+on.quit = function()
+	if Global_state.next_save then
+		save_results()
+		Global_state.next_save = nil
+	end
+end

0026-add_result

@@ -0,0 +1,3 @@
+add_result = function(from, to)
+	table.insert(Global_state.results, {from, to})
+end

0027-delete_result

@@ -0,0 +1,7 @@
+delete_result = function(from, to)
+	for i=1,#Global_state.results do
+		if eq(Global_state.results[i], {from, to}) then
+			table.remove(Global_state.results, i)
+		end
+	end
+end