implement StatefulElement

lib/simple_ui/core/builder.lua

@@ -3,12 +3,14 @@ local Element = require "lib.simple_ui.core.element"
 --- Объект, который отвечает за работу с элементами интерфейса одного экрана
 --- @class UIBuilder
 --- @field builder fun(): UIElement
+--- @field private states {string: table}
 --- @field private elementTree UIElement
 local builder = {}
 builder.__index = builder
 
 --- @return UIBuilder
 local function new(from)
+    from.states = {}
     setmetatable(from, builder)
     return from
 end
@@ -36,7 +38,19 @@ end
 --- @private
 function builder:build_step(cur)
     -- Самоприсваивания должны вырезаться компилятором, я в это верю
-    cur = cur --[[@as SingleChildElement | MultiChildElement]]
+    cur = cur --[[@as SingleChildElement | StatefulElement | MultiChildElement]]
+
+    local key = self:makeKey(cur)
+    if key then
+        cur = cur --[[@as StatefulElement]]
+        local storedState = self.states[key]
+        if not storedState then
+            self.states[key] = cur.state
+        else
+            cur.state = storedState
+        end
+    end
+
     local buildRes = cur:build()
     if not buildRes then return end
 

lib/simple_ui/core/element.lua

@@ -24,12 +24,6 @@ function element:update(dt) end
 
 function element:draw() end
 
---- @param values {[string]: any}
---- @return UIElement
-function element:new(values)
-    return setmetatable(values, self)
-end
-
 --- Рекурсивно обходит дерево элементов вверх, начиная с первого родителя.
 ---
 --- К каждому посещенному элементу применяет функцию visitor.
@@ -42,4 +36,10 @@ function element:traverseUp(visitor)
     return self._parent_:traverseUp(visitor)
 end
 
+--- @param values {[string]: any}
+--- @return UIElement
+function element:new(values)
+    return setmetatable(values, self)
+end
+
 return element

lib/simple_ui/core/stateful_element.lua

@@ -0,0 +1,17 @@
+local SingleChildElement = require "lib.simple_ui.core.single_child_element"
+
+--- @generic T : table
+--- @class StatefulElement<T> : SingleChildElement
+--- @field state T
+local element = setmetatable({}, SingleChildElement)
+element.__index = element
+element.type = "StatefulElement"
+element.state = {}
+
+--- @return StatefulElement<T>
+--- @param values {key: any, state: T?, child: UIElement?}
+function element:new(values)
+    return SingleChildElement.new(self, values)
+end
+
+return element

lib/simple_ui/level/test.lua

@@ -5,28 +5,23 @@ local Builder = require "lib.simple_ui.core.builder"
 local Flex = require "lib.simple_ui.elements.flex"
 local Center = require "lib.simple_ui.elements.center"
 local SizedBox = require "lib.simple_ui.elements.sized_box"
-local SingleChildElement = require "lib.simple_ui.core.single_child_element"
+local StatefulElement = require "lib.simple_ui.core.stateful_element"
 
 
-local MyWidget = setmetatable({}, SingleChildElement)
+local MyWidget = setmetatable({}, StatefulElement)
 MyWidget.__index = MyWidget
 MyWidget.type = "MyWidget"
 
-local Canary = setmetatable({}, SingleChildElement)
+local Canary = setmetatable({}, StatefulElement)
 Canary.__index = Canary
 Canary.type = "Canary"
 
-local reported = false
+--- @class CanaryState
+Canary.state = { i = 0 }
+
 function Canary:build()
-    -- self.i = self.i and self.i + 1 or 0
-    -- print(self.i)
-    if not reported then
-        self:traverseUp(function(element)
-            print(element.type)
-            return true
-        end)
-        reported = true
-    end
+    self.state.i = self.state.i and self.state.i + 1 or 0
+    print(self.state.i)
 
     return Placeholder:new {}
 end
@@ -56,11 +51,20 @@ function MyWidget:build()
                             child = Placeholder:new {}
                         },
                         SizedBox:new {
-                            key = "mybox",
                             width = 100,
                             height = 100,
                             child = Canary:new {
-                                i = 0
+                                key = "canary1",
+                            }
+                        },
+                        SizedBox:new {
+                            width = 100,
+                            height = 100,
+                            child = Canary:new {
+                                key = "canary2",
+                                state = {
+                                    i = 100
+                                }
                             }
                         },
                     },