Add some constructor arguments to some layouts

This adds new constructor arguments to align, fixed and flex which allows adding
widgets directly while creating the layout.

Idea originally by actionless:
https://github.com/awesomeWM/awesome/pull/486#issuecomment-143606301

Closes https://github.com/awesomeWM/awesome/pull/490.

Signed-off-by: Uli Schlachter <psychon@znc.in>

lib/wibox/layout/align.lua

@@ -221,7 +221,7 @@ function align:reset()
     self:emit_signal("widget::layout_changed")
 end
 
-local function get_layout(dir)
+local function get_layout(dir, first, second, third)
     local ret = base.make_widget()
     ret.dir = dir
 
@@ -232,6 +232,9 @@ local function get_layout(dir)
     end
 
     ret:set_expand("inside")
+    ret:set_first(first)
+    ret:set_second(second)
+    ret:set_third(third)
 
     return ret
 end
@@ -240,8 +243,11 @@ end
 -- three widgets. The widget set via :set_left() is left-aligned. :set_right()
 -- sets a widget which will be right-aligned. The remaining space between those
 -- two will be given to the widget set via :set_middle().
-function align.horizontal()
-    local ret = get_layout("x")
+-- @tparam[opt] widget left Widget to be put to the left.
+-- @tparam[opt] widget middle Widget to be put to the middle.
+-- @tparam[opt] widget right Widget to be put to the right.
+function align.horizontal(left, middle, right)
+    local ret = get_layout("x", left, middle, right)
 
     ret.set_left = ret.set_first
     ret.set_middle = ret.set_second
@@ -254,8 +260,11 @@ end
 -- three widgets. The widget set via :set_top() is top-aligned. :set_bottom()
 -- sets a widget which will be bottom-aligned. The remaining space between those
 -- two will be given to the widget set via :set_middle().
-function align.vertical()
-    local ret = get_layout("y")
+-- @tparam[opt] widget top Widget to be put to the top.
+-- @tparam[opt] widget middle Widget to be put to the middle.
+-- @tparam[opt] widget bottom Widget to be put to the right.
+function align.vertical(top, middle, bottom)
+    local ret = get_layout("y", top, middle, bottom)
 
     ret.set_top = ret.set_first
     ret.set_middle = ret.set_second

lib/wibox/layout/fixed.lua

@@ -49,10 +49,16 @@ function fixed:layout(context, width, height)
     return result
 end
 
---- Add a widget to the given fixed layout
-function fixed:add(widget)
-    base.check_widget(widget)
-    table.insert(self.widgets, widget)
+--- Add some widgets to the given fixed layout
+-- @tparam widget ... Widgets that should be added (must at least be one)
+function fixed:add(...)
+    -- No table.pack in Lua 5.1 :-(
+    local args = { n=select('#', ...), ... }
+    assert(args.n > 0, "need at least one widget to add")
+    for i=1, args.n do
+        base.check_widget(args[i])
+        table.insert(self.widgets, args[i])
+    end
     self:emit_signal("widget::layout_changed")
 end
 
@@ -113,7 +119,7 @@ function fixed:fill_space(val)
     end
 end
 
-local function get_layout(dir)
+local function get_layout(dir, widget1, ...)
     local ret = base.make_widget()
 
     for k, v in pairs(fixed) do
@@ -127,21 +133,27 @@ local function get_layout(dir)
     ret:set_spacing(0)
     ret:fill_space(false)
 
+    if widget1 then
+        ret:add(widget1, ...)
+    end
+
     return ret
 end
 
 --- Returns a new horizontal fixed layout. Each widget will get as much space as it
 -- asks for and each widget will be drawn next to its neighboring widget.
--- Widgets can be added via :add().
-function fixed.horizontal()
-    return get_layout("x")
+-- Widgets can be added via :add() or as arguments to this function.
+-- @tparam widget ... Widgets that should be added to the layout.
+function fixed.horizontal(...)
+    return get_layout("x", ...)
 end
 
 --- Returns a new vertical fixed layout. Each widget will get as much space as it
 -- asks for and each widget will be drawn next to its neighboring widget.
--- Widgets can be added via :add().
-function fixed.vertical()
-    return get_layout("y")
+-- Widgets can be added via :add() or as arguments to this function.
+-- @tparam widget ... Widgets that should be added to the layout.
+function fixed.vertical(...)
+    return get_layout("y", ...)
 end
 
 --- Add spacing between each layout widgets

lib/wibox/layout/flex.lua

@@ -96,9 +96,16 @@ function flex:fit(context, orig_width, orig_height)
     return used_in_dir + spacing, used_in_other
 end
 
-function flex:add(widget)
-    base.check_widget(widget)
-    table.insert(self.widgets, widget)
+--- Add some widgets to the given flex layout
+-- @tparam widget ... Widgets that should be added (must at least be one)
+function flex:add(...)
+    -- No table.pack in Lua 5.1 :-(
+    local args = { n=select('#', ...), ... }
+    assert(args.n > 0, "need at least one widget to add")
+    for i=1, args.n do
+        base.check_widget(args[i])
+        table.insert(self.widgets, args[i])
+    end
     self:emit_signal("widget::layout_changed")
 end
 
@@ -127,7 +134,7 @@ function flex:reset()
     self:emit_signal("widget::layout_changed")
 end
 
-local function get_layout(dir)
+local function get_layout(dir, widget1, ...)
     local ret = base.make_widget()
 
     for k, v in pairs(flex) do
@@ -140,19 +147,25 @@ local function get_layout(dir)
     ret.widgets = {}
     ret:set_spacing(0)
 
+    if widget1 then
+        ret:add(widget1, ...)
+    end
+
     return ret
 end
 
 --- Returns a new horizontal flex layout. A flex layout shares the available space
 -- equally among all widgets. Widgets can be added via :add(widget).
-function flex.horizontal()
-    return get_layout("x")
+-- @tparam widget ... Widgets that should be added to the layout.
+function flex.horizontal(...)
+    return get_layout("x", ...)
 end
 
 --- Returns a new vertical flex layout. A flex layout shares the available space
 -- equally among all widgets. Widgets can be added via :add(widget).
-function flex.vertical()
-    return get_layout("y")
+-- @tparam widget ... Widgets that should be added to the layout.
+function flex.vertical(...)
+    return get_layout("y", ...)
 end
 
 return flex

spec/wibox/layout/align_spec.lua

@@ -265,6 +265,19 @@ describe("wibox.layout.align", function()
             layout:set_third(w2)
             assert.is.equal(layout_changed, 2)
         end)
+
+        it("set again", function()
+            local w1, w2, w3 = {}, {}, {}
+            layout = align.vertical(w1, w2, w3)
+            layout:connect_signal("widget::layout_changed", function()
+                layout_changed = layout_changed + 1
+            end)
+            assert.is.equal(layout_changed, 0)
+            layout:set_first(w1)
+            layout:set_second(w2)
+            layout:set_third(w3)
+            assert.is.equal(layout_changed, 0)
+        end)
     end)
 end)
 

spec/wibox/layout/fixed_spec.lua

@@ -22,6 +22,12 @@ describe("wibox.layout.fixed", function()
         assert.widget_layout(layout, { 0, 0 }, {})
     end)
 
+    it("empty add", function()
+        assert.has_error(function()
+            layout:add()
+        end)
+    end)
+
     describe("with widgets", function()
         local first, second, third
 
@@ -30,9 +36,7 @@ describe("wibox.layout.fixed", function()
             second = utils.widget_stub(15, 15)
             third = utils.widget_stub(10, 10)
 
-            layout:add(first)
-            layout:add(second)
-            layout:add(third)
+            layout:add(first, second, third)
         end)
 
         describe("with enough space", function()

spec/wibox/layout/flex_spec.lua

@@ -22,6 +22,12 @@ describe("wibox.layout.flex", function()
         assert.widget_layout(layout, { 0, 0 }, {})
     end)
 
+    it("empty add", function()
+        assert.has_error(function()
+            layout:add()
+        end)
+    end)
+
     describe("with widgets", function()
         local first, second, third
 
@@ -30,9 +36,7 @@ describe("wibox.layout.flex", function()
             second = utils.widget_stub(15, 15)
             third = utils.widget_stub(10, 10)
 
-            layout:add(first)
-            layout:add(second)
-            layout:add(third)
+            layout:add(first, second, third)
         end)
 
         describe("with enough space", function()