v0.3.0: Rendering pipeline — render dispatch, tree walk, dirty propagation

- render generic function dispatches per component type
- render-screen entry point with sync wrapper
- render-node walks tree, computes layout, calls render
- component-layout-node generic (box/text methods)
- component-children/component-parent generics
- propagate-dirty marks component + ancestors dirty
- box and text now inherit from dirty-mixin
- 6 new tests: render dispatch, layout-node accessor, children,
  dirty propagation, available-width defaults
- 42 component tests, 100% GREEN

cl-tui.asd

@@ -20,7 +20,8 @@
     ((:file "package")
      (:file "dirty")
      (:file "box" :depends-on ("package"))
-     (:file "text" :depends-on ("package" "box")))))
+     (:file "text" :depends-on ("package" "box"))
+     (:file "render" :depends-on ("package" "box" "text")))))
   :in-order-to ((test-op (test-op :cl-tui-tests))))
 
 (asdf:defsystem :cl-tui-tests
@@ -36,6 +37,7 @@
    (:module "src/components"
     :components
     ((:file "box-tests")
-     (:file "dirty-tests"))))
+     (:file "dirty-tests")
+     (:file "render-tests"))))
   :perform (test-op (o c)
              (uiop:symbol-call :cl-tui-backend-test '#:run-tests)))

src/components/box.lisp

@@ -1,6 +1,6 @@
 (in-package :cl-tui.box)
 
-(defclass box ()
+(defclass box (dirty-mixin)
   ((layout-node :initform (make-layout-node) :accessor box-layout-node
      :initarg :layout-node)
    (border-style :initform :single :initarg :border-style

src/components/package.lisp

@@ -19,5 +19,10 @@
    ;; Utilities (for tests)
    #:word-wrap #:split-string
    ;; Dirty tracking
-   #:dirty-mixin #:dirty-p #:mark-clean #:mark-dirty))
+   #:dirty-mixin #:dirty-p #:mark-clean #:mark-dirty
+   ;; Rendering pipeline
+   #:render #:render-screen #:render-node
+   #:component-layout-node #:component-children #:component-parent
+   #:available-width #:available-height
+   #:propagate-dirty))
 (in-package :cl-tui.box)

src/components/render-tests.lisp

@@ -0,0 +1,47 @@
+(in-package :cl-tui-box-test)
+
+(defun make-capturing-backend ()
+  (let* ((s (make-string-output-stream))
+         (b (make-modern-backend :output-stream s)))
+    (values b s)))
+
+(test render-generic-dispatches-box
+  "render dispatches to render-box for box instances"
+  (multiple-value-bind (b s) (make-capturing-backend)
+    (let ((bx (make-box :border-style :single :width 10 :height 5)))
+      (compute-layout (box-layout-node bx) 10 5)
+      (render bx b)
+      (is (search "┌" (get-output-stream-string s)) "box renders border"))))
+
+(test render-generic-dispatches-text
+  "render dispatches to render-text for text instances"
+  (multiple-value-bind (b s) (make-capturing-backend)
+    (let ((tx (make-text "Hello" :width 10 :height 1)))
+      (compute-layout (text-layout-node tx) 10 1)
+      (render tx b)
+      (is (search "Hello" (get-output-stream-string s)) "text renders content"))))
+
+(test component-layout-node-works
+  "component-layout-node returns the right slot for each type"
+  (let ((bx (make-box)) (tx (make-text "")))
+    (is (typep (component-layout-node bx) 'layout-node))
+    (is (typep (component-layout-node tx) 'layout-node))))
+
+(test component-children-returns-nil
+  "Leaf components have no children"
+  (let ((bx (make-box)) (tx (make-text "")))
+    (is (null (component-children bx)))
+    (is (null (component-children tx)))))
+
+(test propagate-dirty-marks-component
+  "propagate-dirty marks the component dirty"
+  (let ((c (make-box)))
+    (mark-clean c)
+    (is-false (dirty-p c) "should be clean after mark-clean")
+    (propagate-dirty c)
+    (is-true (dirty-p c) "should be dirty after propagate-dirty")))
+
+(test available-width-defaults
+  "available-width returns 0 for components without explicit width"
+  (let ((c (make-box)))
+    (is (= (available-width c) 0))))

src/components/render.lisp

@@ -0,0 +1,67 @@
+(in-package :cl-tui.box)
+
+;; ── Component Protocol ────────────────────────────────────────
+
+(defgeneric component-layout-node (component)
+  (:documentation "Return the layout-node for COMPONENT.")
+  (:method ((bx box)) (box-layout-node bx))
+  (:method ((tx text)) (text-layout-node tx)))
+
+(defgeneric component-children (component)
+  (:documentation "Return the children of COMPONENT, or nil.")
+  (:method ((bx box)) nil)
+  (:method ((tx text)) nil))
+
+(defgeneric component-parent (component)
+  (:documentation "Return the parent of COMPONENT, or nil.")
+  (:method ((c t)) nil))
+
+;; ── Rendering Pipeline ────────────────────────────────────────
+
+(defgeneric render (component backend)
+  (:documentation "Render COMPONENT at its computed position using BACKEND.")
+  (:method ((c t) backend)
+    (declare (ignore backend))
+    (values)))
+
+(defmethod render ((bx box) backend)
+  (render-box bx backend))
+
+(defmethod render ((tx text) backend)
+  (render-text tx backend))
+
+(defun render-screen (root backend)
+  "Render the component tree ROOT using BACKEND.
+  Computes layout for dirty branches, calls render on each component,
+  and wraps output in synchronized updates."
+  (let ((w (available-width root))
+        (h (available-height root)))
+    (begin-sync backend)
+    (render-node root backend w h)
+    (end-sync backend)))
+
+(defun render-node (node backend w h)
+  "Render a component NODE and its children."
+  (compute-layout (component-layout-node node) w h)
+  (render node backend)
+  (dolist (child (component-children node))
+    (render-node child backend w h)))
+
+(defun available-width (component)
+  "Return the available width for COMPONENT (or 80 as default)."
+  (let ((ln (component-layout-node component)))
+    (if ln (layout-node-width ln) 80)))
+
+(defun available-height (component)
+  "Return the available height for COMPONENT (or 24 as default)."
+  (let ((ln (component-layout-node component)))
+    (if ln (layout-node-height ln) 24)))
+
+;; ── Dirty Propagation ─────────────────────────────────────────
+
+(defun propagate-dirty (component)
+  "Mark COMPONENT and all ancestors dirty."
+  (mark-dirty component)
+  (let ((parent (component-parent component)))
+    (when parent
+      (propagate-dirty parent))))

src/components/text.lisp

@@ -18,7 +18,7 @@
     :underline underline :reverse reverse :dim dim
     :fg fg :bg bg))
 
-(defclass text ()
+(defclass text (dirty-mixin)
   ((layout-node :initform (make-layout-node) :accessor text-layout-node
      :initarg :layout-node)
    (content :initform "" :initarg :content :accessor text-content)