workspace: avoid unnecessary page stealing

When switching to a different desktop, the current code would use the
last-used tag even if it is currently displayed. Instead, keep a
per-desktop stack of free tags and pick the first of those.

1 files changed, 38 insertions, 0 deletions

diff --git a/stack.lua b/stack.lua
new file mode 100644
index 0000000..bee5fd3
--- /dev/null
+++ b/stack.lua
@@ -0,0 +1,38 @@
+local M = {}
+
+local Stack = {}
+
+function Stack:push(v)
+    table.insert(self._et, v)
+end
+
+function Stack:pop()
+    return table.remove(self._et)
+end
+
+function Stack:remove(it)
+    local idx = nil
+    for i, v in ipairs(self._et) do
+        if v == it then
+            idx = i
+            break
+        end
+    end
+    if idx == nil then
+        error(it .. " not in stack")
+    end
+    table.remove(self._et, idx)
+end
+
+function Stack:new()
+    local o = setmetatable({}, self)
+    self.__index = self
+
+    o._et = {}
+
+    return o
+end
+
+M.Stack = Stack
+
+return M