unstash a stashed file

Current design choices:
* Unstashing doesn't delete the file. You have to bump down to the
  scratch screen for that.
* Can't unstash if the file already has local modifications. Decide
  whether to revert or stash them.

0021-draw_menu

@@ -15,11 +15,13 @@ draw_menu = function()
 	x, y = load_button(x, y, r)
 	x, y = paste_button(x, y, r)
 	x, y = copy_button(x, y, r)
-	if Current_pane.filename and has_local_modifications(Current_pane.filename) then
-		if not Current_pane.is_stash then
+	if Current_pane.filename then
+		if has_local_modifications(Current_pane.filename) then
 			x, y = stash_button(x, y, r)
+			x, y = revert_button(x, y, r)
+		elseif can_be_unstashed(Current_pane) then
+			x, y = unstash_button(x, y, r)
 		end
-		x, y = revert_button(x, y, r)
 	end
 	x, y = new_pane_button(x, y, r)
 	x, y = delete_pane_button(x, y, r)

0191-unstash_button

@@ -0,0 +1,3 @@
+unstash_button = function(x,y, r)
+	return overflowable_button('unstash', x, y, r, press_unstash_button)
+end

0192-press_unstash_button

@@ -0,0 +1,5 @@
+press_unstash_button = function()
+	-- disable local modifications to a file without deleting it or saving the pane
+	Show_menu = nil
+	unstash_pane(Current_pane)
+end

0193-unstash_pane

@@ -0,0 +1,12 @@
+unstash_pane = function(pane)
+	local src = Stash_directory..pane.filename
+	local contents, error = love.filesystem.read(src)
+	if not contents then return print_to_output(error) end
+	love.filesystem.createDirectory(Directory)
+	local filename = unstash_filename(pane.filename)
+	local dest = Directory..filename
+	local success, error = love.filesystem.write(dest, contents)
+	if not success then return print_to_output(error) end
+	pane.filename = filename
+	pane.is_stash = nil
+end

0194-unstash_filename

@@ -0,0 +1,3 @@
+unstash_filename = function(filename)
+	return filename:gsub('%..*', '')
+end

0195-can_be_unstashed

@@ -0,0 +1,6 @@
+can_be_unstashed = function(pane)
+	if not pane.is_stash then return end
+	assert(pane.filename)
+	local filename = unstash_filename(pane.filename)
+	return not nativefs.getInfo(App.save_dir..Directory..filename)
+end