From f135b56a1a49a2b2a7d751d59df53ac123499e28 Mon Sep 17 00:00:00 2001
From: Amr Gharbeia <amr@gharbeia.net>
Date: Mon, 11 May 2026 07:18:53 -0400
Subject: [PATCH] =?UTF-8?q?v0.1.0:=20Yoga=20FFI=20binding=20=E2=80=94=20CF?=
 =?UTF-8?q?FI=20types,=2050+=20bound=20functions,=209=20tests?=
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- Load Yoga shared library via CFFI (/usr/local/lib/libyoga.so)
- 15 enum constant sets (YGDirection through YGUnit)
- Foreign type definitions: yg-node-ref, yg-size, yg-value
- Core node management: new, free, insert-child, remove-child, get-child-count
- Layout: calculate-layout, get-left/top/width/height
- Style setters: direction, flex-direction, justify-content, align-items,
  align-self, flex-wrap, position-type, flex-grow/shrink/basis, overflow,
  display, width/height, min/max dimensions, padding, margin, border, gap,
  position (point and percent)
- Style getters: width, height, flex-direction, align-items, justify-content
- Disable FP traps for SBCL (Yoga uses NaN for YGUndefined)

GREEN: 9/9 pass (22 assertions)
- test-node-create-free, test-node-child-count, test-node-insert-child
- test-layout-basic-column, test-layout-basic-row
- test-layout-flex-grow, test-layout-absolute-position
- test-layout-padding, test-layout-nested
---
 cl-tui.asd         |   9 +
 lisp/yoga-ffi.lisp | 631 +++++++++++++++++++++++++++++++++++++
 org/yoga-ffi.org   | 755 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1395 insertions(+)
 create mode 100644 cl-tui.asd
 create mode 100644 lisp/yoga-ffi.lisp
 create mode 100644 org/yoga-ffi.org

diff --git a/cl-tui.asd b/cl-tui.asd
new file mode 100644
index 0000000..3484e26
--- /dev/null
+++ b/cl-tui.asd
@@ -0,0 +1,9 @@
+(defsystem :cl-tui
+  :name "cl-tui"
+  :author "memex"
+  :version "0.1.0"
+  :license "AGPLv3"
+  :description "Reusable Common Lisp Terminal UI Framework"
+  :depends-on (:cffi :croatoan)
+  :serial t
+  :components ((:file "lisp/yoga-ffi")))
diff --git a/lisp/yoga-ffi.lisp b/lisp/yoga-ffi.lisp
new file mode 100644
index 0000000..a683413
--- /dev/null
+++ b/lisp/yoga-ffi.lisp
@@ -0,0 +1,631 @@
+(eval-when (:compile-toplevel :load-toplevel :execute)
+  (ql:quickload :cffi :silent t))
+
+(defpackage :cl-tui.yoga-ffi
+  (:use :cl)
+  (:export
+   ;; library
+   #:*libyoga*
+   #:load-yoga
+   ;; constants
+   #:+yg-direction-inherit+
+   #:+yg-direction-ltr+
+   #:+yg-direction-rtl+
+   #:+yg-flex-direction-column+
+   #:+yg-flex-direction-column-reverse+
+   #:+yg-flex-direction-row+
+   #:+yg-flex-direction-row-reverse+
+   #:+yg-justify-auto+
+   #:+yg-justify-flex-start+
+   #:+yg-justify-center+
+   #:+yg-justify-flex-end+
+   #:+yg-justify-space-between+
+   #:+yg-justify-space-around+
+   #:+yg-justify-space-evenly+
+   #:+yg-justify-stretch+
+   #:+yg-align-auto+
+   #:+yg-align-flex-start+
+   #:+yg-align-center+
+   #:+yg-align-flex-end+
+   #:+yg-align-stretch+
+   #:+yg-align-baseline+
+   #:+yg-align-space-between+
+   #:+yg-align-space-around+
+   #:+yg-align-space-evenly+
+   #:+yg-wrap-nowrap+
+   #:+yg-wrap-wrap+
+   #:+yg-wrap-wrap-reverse+
+   #:+yg-position-type-static+
+   #:+yg-position-type-relative+
+   #:+yg-position-type-absolute+
+   #:+yg-overflow-visible+
+   #:+yg-overflow-hidden+
+   #:+yg-overflow-scroll+
+   #:+yg-display-flex+
+   #:+yg-display-none+
+   #:+yg-display-contents+
+   #:+yg-edge-left+
+   #:+yg-edge-top+
+   #:+yg-edge-right+
+   #:+yg-edge-bottom+
+   #:+yg-edge-start+
+   #:+yg-edge-end+
+   #:+yg-edge-horizontal+
+   #:+yg-edge-vertical+
+   #:+yg-edge-all+
+   #:+yg-gutter-column+
+   #:+yg-gutter-row+
+   #:+yg-gutter-all+
+   #:+yg-unit-undefined+
+   #:+yg-unit-point+
+   #:+yg-unit-percent+
+   #:+yg-unit-auto+
+   ;; types
+   #:yg-node-ref
+   #:yg-node-const-ref
+   ;; node management
+   #:yg-node-new
+   #:yg-node-free
+   #:yg-node-free-recursive
+   #:yg-node-insert-child
+   #:yg-node-remove-child
+   #:yg-node-remove-all-children
+   #:yg-node-get-child-count
+   #:yg-node-get-child
+   ;; layout
+   #:yg-node-calculate-layout
+   #:yg-node-layout-get-left
+   #:yg-node-layout-get-top
+   #:yg-node-layout-get-width
+   #:yg-node-layout-get-height
+   #:yg-node-layout-get-right
+   #:yg-node-layout-get-bottom
+   #:yg-node-is-dirty
+   #:yg-node-mark-dirty
+   ;; style direction & flex
+   #:yg-node-style-set-direction
+   #:yg-node-style-set-flex-direction
+   #:yg-node-style-set-justify-content
+   #:yg-node-style-set-align-items
+   #:yg-node-style-set-align-self
+   #:yg-node-style-set-align-content
+   #:yg-node-style-set-flex-wrap
+   #:yg-node-style-set-position-type
+   #:yg-node-style-set-flex-grow
+   #:yg-node-style-set-flex-shrink
+   #:yg-node-style-set-flex-basis
+   #:yg-node-style-set-flex-basis-auto
+   #:yg-node-style-set-flex-basis-percent
+   #:yg-node-style-set-overflow
+   #:yg-node-style-set-display
+   ;; style dimensions
+   #:yg-node-style-set-width
+   #:yg-node-style-set-width-percent
+   #:yg-node-style-set-width-auto
+   #:yg-node-style-set-height
+   #:yg-node-style-set-height-percent
+   #:yg-node-style-set-height-auto
+   #:yg-node-style-set-min-width
+   #:yg-node-style-set-min-width-percent
+   #:yg-node-style-set-min-height
+   #:yg-node-style-set-min-height-percent
+   #:yg-node-style-set-max-width
+   #:yg-node-style-set-max-height
+   #:yg-node-style-set-aspect-ratio
+   ;; style padding/margin/border/gap/position
+   #:yg-node-style-set-padding
+   #:yg-node-style-set-padding-percent
+   #:yg-node-style-set-margin
+   #:yg-node-style-set-margin-percent
+   #:yg-node-style-set-margin-auto
+   #:yg-node-style-set-border
+   #:yg-node-style-set-gap
+   #:yg-node-style-set-position
+   #:yg-node-style-set-position-percent
+   ;; style getters
+   #:yg-node-style-get-width
+   #:yg-node-style-get-height
+   #:yg-node-style-get-flex-direction
+   #:yg-node-style-get-align-items
+   #:yg-node-style-get-justify-content))
+
+(in-package :cl-tui.yoga-ffi)
+
+(defparameter *libyoga* nil "Handle for the loaded Yoga shared library.")
+
+(defun load-yoga ()
+  "Load the Yoga shared library via CFFI."
+  (setf *libyoga* (cffi:load-foreign-library "/usr/local/lib/libyoga.so"))
+  (sb-int:set-floating-point-modes :traps '())
+  *libyoga*)
+
+(load-yoga)
+
+(eval-when (:compile-toplevel :load-toplevel :execute)
+  ;; YGDirection
+  (defconstant +yg-direction-inherit+ 0)
+  (defconstant +yg-direction-ltr+ 1)
+  (defconstant +yg-direction-rtl+ 2)
+  ;; YGFlexDirection
+  (defconstant +yg-flex-direction-column+ 0)
+  (defconstant +yg-flex-direction-column-reverse+ 1)
+  (defconstant +yg-flex-direction-row+ 2)
+  (defconstant +yg-flex-direction-row-reverse+ 3)
+  ;; YGJustify
+  (defconstant +yg-justify-auto+ 0)
+  (defconstant +yg-justify-flex-start+ 1)
+  (defconstant +yg-justify-center+ 2)
+  (defconstant +yg-justify-flex-end+ 3)
+  (defconstant +yg-justify-space-between+ 4)
+  (defconstant +yg-justify-space-around+ 5)
+  (defconstant +yg-justify-space-evenly+ 6)
+  (defconstant +yg-justify-stretch+ 7)
+  ;; YGAlign
+  (defconstant +yg-align-auto+ 0)
+  (defconstant +yg-align-flex-start+ 1)
+  (defconstant +yg-align-center+ 2)
+  (defconstant +yg-align-flex-end+ 3)
+  (defconstant +yg-align-stretch+ 4)
+  (defconstant +yg-align-baseline+ 5)
+  (defconstant +yg-align-space-between+ 6)
+  (defconstant +yg-align-space-around+ 7)
+  (defconstant +yg-align-space-evenly+ 8)
+  ;; YGWrap
+  (defconstant +yg-wrap-nowrap+ 0)
+  (defconstant +yg-wrap-wrap+ 1)
+  (defconstant +yg-wrap-wrap-reverse+ 2)
+  ;; YGPositionType
+  (defconstant +yg-position-type-static+ 0)
+  (defconstant +yg-position-type-relative+ 1)
+  (defconstant +yg-position-type-absolute+ 2)
+  ;; YGOverflow
+  (defconstant +yg-overflow-visible+ 0)
+  (defconstant +yg-overflow-hidden+ 1)
+  (defconstant +yg-overflow-scroll+ 2)
+  ;; YGDisplay
+  (defconstant +yg-display-flex+ 0)
+  (defconstant +yg-display-none+ 1)
+  (defconstant +yg-display-contents+ 2)
+  ;; YGEdge
+  (defconstant +yg-edge-left+ 0)
+  (defconstant +yg-edge-top+ 1)
+  (defconstant +yg-edge-right+ 2)
+  (defconstant +yg-edge-bottom+ 3)
+  (defconstant +yg-edge-start+ 4)
+  (defconstant +yg-edge-end+ 5)
+  (defconstant +yg-edge-horizontal+ 6)
+  (defconstant +yg-edge-vertical+ 7)
+  (defconstant +yg-edge-all+ 8)
+  ;; YGGutter
+  (defconstant +yg-gutter-column+ 0)
+  (defconstant +yg-gutter-row+ 1)
+  (defconstant +yg-gutter-all+ 2)
+  ;; YGUnit
+  (defconstant +yg-unit-undefined+ 0)
+  (defconstant +yg-unit-point+ 1)
+  (defconstant +yg-unit-percent+ 2)
+  (defconstant +yg-unit-auto+ 3))
+
+(cffi:defctype yg-node-ref :pointer)
+(cffi:defctype yg-node-const-ref :pointer)
+
+(cffi:defcstruct yg-size
+  (width :float)
+  (height :float))
+
+(cffi:defcstruct yg-value
+  (value :float)
+  (unit :int))
+
+(cffi:defcfun ("YGNodeNew" yg-node-new) yg-node-ref)
+
+(cffi:defcfun ("YGNodeFree" yg-node-free) :void
+  (node yg-node-ref))
+
+(cffi:defcfun ("YGNodeFreeRecursive" yg-node-free-recursive) :void
+  (node yg-node-ref))
+
+(cffi:defcfun ("YGNodeInsertChild" yg-node-insert-child) :void
+  (node yg-node-ref)
+  (child yg-node-ref)
+  (index :unsigned-int))
+
+(cffi:defcfun ("YGNodeRemoveChild" yg-node-remove-child) :void
+  (node yg-node-ref)
+  (child yg-node-ref))
+
+(cffi:defcfun ("YGNodeRemoveAllChildren" yg-node-remove-all-children) :void
+  (node yg-node-ref))
+
+(cffi:defcfun ("YGNodeGetChildCount" yg-node-get-child-count) :unsigned-int
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeGetChild" yg-node-get-child) yg-node-ref
+  (node yg-node-ref)
+  (index :unsigned-int))
+
+(cffi:defcfun ("YGNodeCalculateLayout" yg-node-calculate-layout) :void
+  (node yg-node-ref)
+  (available-width :float)
+  (available-height :float)
+  (owner-direction :int))
+
+(cffi:defcfun ("YGNodeLayoutGetLeft" yg-node-layout-get-left) :float
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeLayoutGetTop" yg-node-layout-get-top) :float
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeLayoutGetWidth" yg-node-layout-get-width) :float
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeLayoutGetHeight" yg-node-layout-get-height) :float
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeLayoutGetRight" yg-node-layout-get-right) :float
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeLayoutGetBottom" yg-node-layout-get-bottom) :float
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeIsDirty" yg-node-is-dirty) :boolean
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeMarkDirty" yg-node-mark-dirty) :void
+  (node yg-node-ref))
+
+(cffi:defcfun ("YGNodeStyleSetDirection" yg-node-style-set-direction) :void
+  (node yg-node-ref)
+  (direction :int))
+
+(cffi:defcfun ("YGNodeStyleSetFlexDirection" yg-node-style-set-flex-direction) :void
+  (node yg-node-ref)
+  (flex-direction :int))
+
+(cffi:defcfun ("YGNodeStyleSetJustifyContent" yg-node-style-set-justify-content) :void
+  (node yg-node-ref)
+  (justify :int))
+
+(cffi:defcfun ("YGNodeStyleSetAlignItems" yg-node-style-set-align-items) :void
+  (node yg-node-ref)
+  (align :int))
+
+(cffi:defcfun ("YGNodeStyleSetAlignSelf" yg-node-style-set-align-self) :void
+  (node yg-node-ref)
+  (align :int))
+
+(cffi:defcfun ("YGNodeStyleSetAlignContent" yg-node-style-set-align-content) :void
+  (node yg-node-ref)
+  (align :int))
+
+(cffi:defcfun ("YGNodeStyleSetFlexWrap" yg-node-style-set-flex-wrap) :void
+  (node yg-node-ref)
+  (wrap :int))
+
+(cffi:defcfun ("YGNodeStyleSetPositionType" yg-node-style-set-position-type) :void
+  (node yg-node-ref)
+  (position-type :int))
+
+(cffi:defcfun ("YGNodeStyleSetFlexGrow" yg-node-style-set-flex-grow) :void
+  (node yg-node-ref)
+  (flex-grow :float))
+
+(cffi:defcfun ("YGNodeStyleSetFlexShrink" yg-node-style-set-flex-shrink) :void
+  (node yg-node-ref)
+  (flex-shrink :float))
+
+(cffi:defcfun ("YGNodeStyleSetFlexBasis" yg-node-style-set-flex-basis) :void
+  (node yg-node-ref)
+  (flex-basis :float))
+
+(cffi:defcfun ("YGNodeStyleSetFlexBasisAuto" yg-node-style-set-flex-basis-auto) :void
+  (node yg-node-ref))
+
+(cffi:defcfun ("YGNodeStyleSetFlexBasisPercent" yg-node-style-set-flex-basis-percent) :void
+  (node yg-node-ref)
+  (flex-basis :float))
+
+(cffi:defcfun ("YGNodeStyleSetOverflow" yg-node-style-set-overflow) :void
+  (node yg-node-ref)
+  (overflow :int))
+
+(cffi:defcfun ("YGNodeStyleSetDisplay" yg-node-style-set-display) :void
+  (node yg-node-ref)
+  (display :int))
+
+(cffi:defcfun ("YGNodeStyleSetWidth" yg-node-style-set-width) :void
+  (node yg-node-ref)
+  (width :float))
+
+(cffi:defcfun ("YGNodeStyleSetWidthPercent" yg-node-style-set-width-percent) :void
+  (node yg-node-ref)
+  (width :float))
+
+(cffi:defcfun ("YGNodeStyleSetWidthAuto" yg-node-style-set-width-auto) :void
+  (node yg-node-ref))
+
+(cffi:defcfun ("YGNodeStyleSetHeight" yg-node-style-set-height) :void
+  (node yg-node-ref)
+  (height :float))
+
+(cffi:defcfun ("YGNodeStyleSetHeightPercent" yg-node-style-set-height-percent) :void
+  (node yg-node-ref)
+  (height :float))
+
+(cffi:defcfun ("YGNodeStyleSetHeightAuto" yg-node-style-set-height-auto) :void
+  (node yg-node-ref))
+
+(cffi:defcfun ("YGNodeStyleSetMinWidth" yg-node-style-set-min-width) :void
+  (node yg-node-ref)
+  (min-width :float))
+
+(cffi:defcfun ("YGNodeStyleSetMinWidthPercent" yg-node-style-set-min-width-percent) :void
+  (node yg-node-ref)
+  (min-width :float))
+
+(cffi:defcfun ("YGNodeStyleSetMinHeight" yg-node-style-set-min-height) :void
+  (node yg-node-ref)
+  (min-height :float))
+
+(cffi:defcfun ("YGNodeStyleSetMinHeightPercent" yg-node-style-set-min-height-percent) :void
+  (node yg-node-ref)
+  (min-height :float))
+
+(cffi:defcfun ("YGNodeStyleSetMaxWidth" yg-node-style-set-max-width) :void
+  (node yg-node-ref)
+  (max-width :float))
+
+(cffi:defcfun ("YGNodeStyleSetMaxHeight" yg-node-style-set-max-height) :void
+  (node yg-node-ref)
+  (max-height :float))
+
+(cffi:defcfun ("YGNodeStyleSetAspectRatio" yg-node-style-set-aspect-ratio) :void
+  (node yg-node-ref)
+  (aspect-ratio :float))
+
+(cffi:defcfun ("YGNodeStyleSetPadding" yg-node-style-set-padding) :void
+  (node yg-node-ref)
+  (edge :int)
+  (padding :float))
+
+(cffi:defcfun ("YGNodeStyleSetPaddingPercent" yg-node-style-set-padding-percent) :void
+  (node yg-node-ref)
+  (edge :int)
+  (padding :float))
+
+(cffi:defcfun ("YGNodeStyleSetMargin" yg-node-style-set-margin) :void
+  (node yg-node-ref)
+  (edge :int)
+  (margin :float))
+
+(cffi:defcfun ("YGNodeStyleSetMarginPercent" yg-node-style-set-margin-percent) :void
+  (node yg-node-ref)
+  (edge :int)
+  (margin :float))
+
+(cffi:defcfun ("YGNodeStyleSetMarginAuto" yg-node-style-set-margin-auto) :void
+  (node yg-node-ref)
+  (edge :int))
+
+(cffi:defcfun ("YGNodeStyleSetBorder" yg-node-style-set-border) :void
+  (node yg-node-ref)
+  (edge :int)
+  (border :float))
+
+(cffi:defcfun ("YGNodeStyleSetGap" yg-node-style-set-gap) :void
+  (node yg-node-ref)
+  (gutter :int)
+  (gap :float))
+
+(cffi:defcfun ("YGNodeStyleSetPosition" yg-node-style-set-position) :void
+  (node yg-node-ref)
+  (edge :int)
+  (position :float))
+
+(cffi:defcfun ("YGNodeStyleSetPositionPercent" yg-node-style-set-position-percent) :void
+  (node yg-node-ref)
+  (edge :int)
+  (position :float))
+
+(cffi:defcfun ("YGNodeStyleGetWidth" yg-node-style-get-width) yg-value
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeStyleGetHeight" yg-node-style-get-height) yg-value
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeStyleGetFlexDirection" yg-node-style-get-flex-direction) :int
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeStyleGetAlignItems" yg-node-style-get-align-items) :int
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeStyleGetJustifyContent" yg-node-style-get-justify-content) :int
+  (node yg-node-const-ref))
+
+(eval-when (:compile-toplevel :load-toplevel :execute)
+  (ql:quickload :fiveam :silent t))
+
+(defpackage :cl-tui.yoga-ffi-tests
+  (:use :cl :fiveam)
+  (:import-from :cl-tui.yoga-ffi
+   #:load-yoga
+   #:yg-node-new
+   #:yg-node-free
+   #:yg-node-free-recursive
+   #:yg-node-insert-child
+   #:yg-node-get-child-count
+   #:yg-node-calculate-layout
+   #:yg-node-layout-get-left
+   #:yg-node-layout-get-top
+   #:yg-node-layout-get-width
+   #:yg-node-layout-get-height
+   #:yg-node-style-set-flex-direction
+   #:yg-node-style-set-justify-content
+   #:yg-node-style-set-align-items
+   #:yg-node-style-set-width
+   #:yg-node-style-set-height
+   #:yg-node-style-set-padding
+   #:yg-node-style-set-margin
+   #:yg-node-style-set-flex-grow
+   #:yg-node-style-set-position-type
+   #:yg-node-style-set-position
+   #:+yg-flex-direction-column+
+   #:+yg-flex-direction-row+
+   #:+yg-justify-center+
+   #:+yg-justify-flex-start+
+   #:+yg-align-stretch+
+   #:+yg-align-center+
+   #:+yg-edge-all+
+   #:+yg-edge-left+
+   #:+yg-edge-top+
+   #:+yg-edge-right+
+   #:+yg-edge-bottom+
+   #:+yg-position-type-relative+
+   #:+yg-position-type-absolute+
+   ;; YGDirection constants (different from YGFlexDirection!)
+   #:+yg-direction-inherit+
+   #:+yg-direction-ltr+
+   #:+yg-direction-rtl+))
+
+(in-package :cl-tui.yoga-ffi-tests)
+
+(fiveam:def-suite yoga-ffi-suite
+  :description "Yoga FFI binding verification")
+(fiveam:in-suite yoga-ffi-suite)
+
+(fiveam:test test-node-create-free
+  "Contract: yg-node-new returns a non-null pointer; yg-node-free doesn't crash."
+  (let ((node (yg-node-new)))
+    (fiveam:is (not (cffi:null-pointer-p node)))
+    (yg-node-free node)
+    (fiveam:pass)))
+
+(fiveam:test test-node-child-count
+  "Contract: yg-node-get-child-count returns 0 for a new node."
+  (let ((node (yg-node-new)))
+    (fiveam:is (= 0 (yg-node-get-child-count node)))
+    (yg-node-free node)))
+
+(fiveam:test test-node-insert-child
+  "Contract: inserting a child increments the child count."
+  (let ((parent (yg-node-new))
+        (child (yg-node-new)))
+    (yg-node-insert-child parent child 0)
+    (fiveam:is (= 1 (yg-node-get-child-count parent)))
+    (yg-node-free-recursive parent)))
+
+(fiveam:test test-layout-basic-column
+  "Contract: a column with two fixed-height children positions them vertically."
+  (let* ((root (yg-node-new)))
+    (yg-node-style-set-width root 100.0)
+    (yg-node-style-set-height root 200.0)
+    (yg-node-style-set-flex-direction root +yg-flex-direction-column+)
+    (let ((child1 (yg-node-new))
+          (child2 (yg-node-new)))
+      (yg-node-style-set-width child1 100.0)
+      (yg-node-style-set-height child1 50.0)
+      (yg-node-style-set-width child2 100.0)
+      (yg-node-style-set-height child2 50.0)
+      (yg-node-insert-child root child1 0)
+      (yg-node-insert-child root child2 1)
+      (yg-node-calculate-layout root 100.0 200.0 +yg-direction-ltr+)
+      (fiveam:is (= 0.0 (yg-node-layout-get-left child1)))
+      (fiveam:is (= 0.0 (yg-node-layout-get-top child1)))
+      (fiveam:is (= 50.0 (yg-node-layout-get-top child2)))
+      (yg-node-free-recursive root))))
+
+(fiveam:test test-layout-basic-row
+  "Contract: a row with two fixed-width children positions them horizontally."
+  (let* ((root (yg-node-new)))
+    (yg-node-style-set-width root 200.0)
+    (yg-node-style-set-height root 100.0)
+    (yg-node-style-set-flex-direction root +yg-flex-direction-row+)
+    (let ((child1 (yg-node-new))
+          (child2 (yg-node-new)))
+      (yg-node-style-set-width child1 80.0)
+      (yg-node-style-set-height child1 50.0)
+      (yg-node-style-set-width child2 80.0)
+      (yg-node-style-set-height child2 50.0)
+      (yg-node-insert-child root child1 0)
+      (yg-node-insert-child root child2 1)
+      (yg-node-calculate-layout root 200.0 100.0 +yg-direction-ltr+)
+      (fiveam:is (= 0.0 (yg-node-layout-get-left child1)))
+      (fiveam:is (= 0.0 (yg-node-layout-get-top child1)))
+      (fiveam:is (= 80.0 (yg-node-layout-get-left child2)))
+      (yg-node-free-recursive root))))
+
+(fiveam:test test-layout-flex-grow
+  "Contract: flex-grow distributes remaining space proportionally."
+  (let* ((root (yg-node-new)))
+    (yg-node-style-set-width root 200.0)
+    (yg-node-style-set-height root 100.0)
+    (yg-node-style-set-flex-direction root +yg-flex-direction-row+)
+    (let ((child1 (yg-node-new))
+          (child2 (yg-node-new)))
+      (yg-node-style-set-height child1 100.0)
+      (yg-node-style-set-flex-grow child1 1.0)
+      (yg-node-style-set-height child2 100.0)
+      (yg-node-style-set-flex-grow child2 2.0)
+      (yg-node-insert-child root child1 0)
+      (yg-node-insert-child root child2 1)
+      (yg-node-calculate-layout root 200.0 100.0 +yg-direction-ltr+)
+      (fiveam:is (< 0.0 (yg-node-layout-get-width child1)))
+      (fiveam:is (< 0.0 (yg-node-layout-get-width child2)))
+      (fiveam:is (= 200.0 (+ (yg-node-layout-get-width child1)
+                             (yg-node-layout-get-width child2))))
+      (yg-node-free-recursive root))))
+
+(fiveam:test test-layout-absolute-position
+  "Contract: an absolute child positions relative to its parent."
+  (let* ((root (yg-node-new)))
+    (yg-node-style-set-width root 300.0)
+    (yg-node-style-set-height root 300.0)
+    (let ((child (yg-node-new)))
+      (yg-node-style-set-width child 50.0)
+      (yg-node-style-set-height child 50.0)
+      (yg-node-style-set-position-type child +yg-position-type-absolute+)
+      (yg-node-style-set-position child +yg-edge-left+ 100.0)
+      (yg-node-style-set-position child +yg-edge-top+ 50.0)
+      (yg-node-insert-child root child 0)
+      (yg-node-calculate-layout root 300.0 300.0 +yg-direction-ltr+)
+      (fiveam:is (= 100.0 (yg-node-layout-get-left child)))
+      (fiveam:is (= 50.0 (yg-node-layout-get-top child)))
+      (fiveam:is (= 50.0 (yg-node-layout-get-width child)))
+      (fiveam:is (= 50.0 (yg-node-layout-get-height child)))
+      (yg-node-free-recursive root))))
+
+(fiveam:test test-layout-padding
+  "Contract: padding reduces the available space for children."
+  (let* ((root (yg-node-new)))
+    (yg-node-style-set-width root 200.0)
+    (yg-node-style-set-height root 100.0)
+    (yg-node-style-set-padding root +yg-edge-all+ 10.0)
+    (let ((child (yg-node-new)))
+      (yg-node-style-set-width child 180.0)
+      (yg-node-style-set-height child 80.0)
+      (yg-node-insert-child root child 0)
+      (yg-node-calculate-layout root 200.0 100.0 +yg-direction-ltr+)
+      (fiveam:is (= 10.0 (yg-node-layout-get-left child)))
+      (fiveam:is (= 10.0 (yg-node-layout-get-top child)))
+      (yg-node-free-recursive root))))
+
+(fiveam:test test-layout-nested
+  "Contract: nested containers produce correct leaf positions."
+  (let* ((root (yg-node-new)))
+    (yg-node-style-set-width root 400.0)
+    (yg-node-style-set-height root 400.0)
+    (yg-node-style-set-flex-direction root +yg-flex-direction-column+)
+    (let ((outer (yg-node-new)))
+      (yg-node-style-set-width outer 400.0)
+      (yg-node-style-set-height outer 200.0)
+      (yg-node-style-set-flex-direction outer +yg-flex-direction-row+)
+      (let ((inner (yg-node-new)))
+        (yg-node-style-set-width inner 100.0)
+        (yg-node-style-set-height inner 100.0)
+        (yg-node-insert-child outer inner 0)
+        (yg-node-insert-child root outer 0)
+        (yg-node-calculate-layout root 400.0 400.0 +yg-direction-ltr+)
+        (fiveam:is (= 0.0 (yg-node-layout-get-left inner)))
+        (fiveam:is (= 100.0 (yg-node-layout-get-width inner)))
+        (fiveam:is (= 100.0 (yg-node-layout-get-height inner)))
+        (yg-node-free-recursive root)))))
diff --git a/org/yoga-ffi.org b/org/yoga-ffi.org
new file mode 100644
index 0000000..62208c9
--- /dev/null
+++ b/org/yoga-ffi.org
@@ -0,0 +1,755 @@
+#+TITLE: Yoga FFI Binding
+#+STARTUP: content
+#+FILETAGS: :cl-tui:yoga-ffi:v010:
+
+* Yoga FFI Binding
+
+CFFI bindings for Facebook's Yoga Flexbox layout engine. Provides raw access
+to the C library — node management, style setters, layout calculation, and
+layout getters. The next file (=layout-primitives.org=) wraps these in CLOS.
+
+The Yoga shared library is at =/usr/local/lib/libyoga.so=, built from
+=facebook/yoga= with C++17.
+
+** Contract
+
+- =(load-yoga)= :: loads the shared library via CFFI. Signal an error if the
+  library cannot be found.
+- =(yg-node-new)= → YGNodeRef :: wraps =YGNodeNew=. Allocates a new Yoga node.
+- =(yg-node-free node)= :: wraps =YGNodeFree=. Frees a node and detaches it
+  from its owner and children.
+- =(yg-node-free-recursive node)= :: wraps =YGNodeFreeRecursive=. Frees the
+  entire subtree.
+- =(yg-node-insert-child node child index)= :: wraps =YGNodeInsertChild=.
+  Inserts a child at the given index.
+- =(yg-node-remove-child node child)= :: wraps =YGNodeRemoveChild=.
+- =(yg-node-get-child-count node)= → integer :: wraps =YGNodeGetChildCount=.
+- =(yg-node-calculate-layout node width height direction)= ::
+  wraps =YGNodeCalculateLayout=. Runs the layout algorithm.
+- =(yg-node-layout-get-left node)= → float :: wraps =YGNodeLayoutGetLeft=.
+  Returns the computed X position.
+- =(yg-node-layout-get-top node)= → float :: wraps =YGNodeLayoutGetTop=.
+  Returns the computed Y position.
+- =(yg-node-layout-get-width node)= → float :: wraps =YGNodeLayoutGetWidth=.
+  Returns the computed width.
+- =(yg-node-layout-get-height node)= → float :: wraps =YGNodeLayoutGetHeight=.
+  Returns the computed height.
+- =(yg-node-style-set-direction node dir)= :: sets the text direction.
+- =(yg-node-style-set-flex-direction node dir)= :: sets the flex direction.
+- =(yg-node-style-set-justify-content node justify)= :: sets main-axis
+  alignment.
+- =(yg-node-style-set-align-items node align)= :: sets cross-axis alignment.
+- =(yg-node-style-set-align-self node align)= :: sets self alignment.
+- =(yg-node-style-set-flex-wrap node wrap)= :: sets wrapping mode.
+- =(yg-node-style-set-flex-grow node value)= :: sets the flex grow factor.
+- =(yg-node-style-set-flex-shrink node value)= :: sets the flex shrink factor.
+- =(yg-node-style-set-position-type node type)= :: sets positioning type.
+- =(yg-node-style-set-width node points)= :: sets width in points.
+- =(yg-node-style-set-width-percent node pct)= :: sets width as percentage.
+- =(yg-node-style-set-width-auto node)= :: sets width to auto.
+- =(yg-node-style-set-height node points)= :: sets height in points.
+- =(yg-node-style-set-height-percent node pct)= :: sets height as percentage.
+- =(yg-node-style-set-height-auto node)= :: sets height to auto.
+- =(yg-node-style-set-padding node edge points)= :: sets padding on an edge.
+- =(yg-node-style-set-margin node edge points)= :: sets margin on an edge.
+- =(yg-node-style-set-border node edge points)= :: sets border on an edge.
+- =(yg-node-style-set-gap node gutter length)= :: sets gap between children.
+- =(yg-node-style-set-overflow node overflow)= :: sets overflow mode.
+- =(yg-node-style-set-display node display)= :: sets display mode.
+- =(yg-node-style-set-position-percent node edge pct)= :: sets position as
+  percentage.
+- =(yg-node-style-set-position node edge points)= :: sets position in points.
+
+Enum keywords (mapping C enum → Lisp keyword):
+- YGDirection: :inherit (0), :ltr (1), :rtl (2)
+- YGFlexDirection: :column (0), :column-reverse (1), :row (2), :row-reverse (3)
+- YGJustify: :auto (0), :flex-start (1), :center (2), :flex-end (3),
+  :space-between (4), :space-around (5), :space-evenly (6), :stretch (7)
+- YGAlign: :auto (0), :flex-start (1), :center (2), :flex-end (3),
+  :stretch (4), :baseline (5), :space-between (6), :space-around (7),
+  :space-evenly (8)
+- YGWrap: :nowrap (0), :wrap (1), :wrap-reverse (2)
+- YGPositionType: :static (0), :relative (1), :absolute (2)
+- YGOverflow: :visible (0), :hidden (1), :scroll (2)
+- YGDisplay: :flex (0), :none (1), :contents (2)
+- YGEdge: :left (0), :top (1), :right (2), :bottom (3), :start (4), :end (5),
+  :horizontal (6), :vertical (7), :all (8)
+- YGGutter: :column (0), :row (1), :all (2)
+- YGUnit: :undefined (0), :point (1), :percent (2), :auto (3)
+
+* Application-Level Package
+
+#+begin_src lisp
+(eval-when (:compile-toplevel :load-toplevel :execute)
+  (ql:quickload :cffi :silent t))
+
+(defpackage :cl-tui.yoga-ffi
+  (:use :cl)
+  (:export
+   ;; library
+   #:*libyoga*
+   #:load-yoga
+   ;; constants
+   #:+yg-direction-inherit+
+   #:+yg-direction-ltr+
+   #:+yg-direction-rtl+
+   #:+yg-flex-direction-column+
+   #:+yg-flex-direction-column-reverse+
+   #:+yg-flex-direction-row+
+   #:+yg-flex-direction-row-reverse+
+   #:+yg-justify-auto+
+   #:+yg-justify-flex-start+
+   #:+yg-justify-center+
+   #:+yg-justify-flex-end+
+   #:+yg-justify-space-between+
+   #:+yg-justify-space-around+
+   #:+yg-justify-space-evenly+
+   #:+yg-justify-stretch+
+   #:+yg-align-auto+
+   #:+yg-align-flex-start+
+   #:+yg-align-center+
+   #:+yg-align-flex-end+
+   #:+yg-align-stretch+
+   #:+yg-align-baseline+
+   #:+yg-align-space-between+
+   #:+yg-align-space-around+
+   #:+yg-align-space-evenly+
+   #:+yg-wrap-nowrap+
+   #:+yg-wrap-wrap+
+   #:+yg-wrap-wrap-reverse+
+   #:+yg-position-type-static+
+   #:+yg-position-type-relative+
+   #:+yg-position-type-absolute+
+   #:+yg-overflow-visible+
+   #:+yg-overflow-hidden+
+   #:+yg-overflow-scroll+
+   #:+yg-display-flex+
+   #:+yg-display-none+
+   #:+yg-display-contents+
+   #:+yg-edge-left+
+   #:+yg-edge-top+
+   #:+yg-edge-right+
+   #:+yg-edge-bottom+
+   #:+yg-edge-start+
+   #:+yg-edge-end+
+   #:+yg-edge-horizontal+
+   #:+yg-edge-vertical+
+   #:+yg-edge-all+
+   #:+yg-gutter-column+
+   #:+yg-gutter-row+
+   #:+yg-gutter-all+
+   #:+yg-unit-undefined+
+   #:+yg-unit-point+
+   #:+yg-unit-percent+
+   #:+yg-unit-auto+
+   ;; types
+   #:yg-node-ref
+   #:yg-node-const-ref
+   ;; node management
+   #:yg-node-new
+   #:yg-node-free
+   #:yg-node-free-recursive
+   #:yg-node-insert-child
+   #:yg-node-remove-child
+   #:yg-node-remove-all-children
+   #:yg-node-get-child-count
+   #:yg-node-get-child
+   ;; layout
+   #:yg-node-calculate-layout
+   #:yg-node-layout-get-left
+   #:yg-node-layout-get-top
+   #:yg-node-layout-get-width
+   #:yg-node-layout-get-height
+   #:yg-node-layout-get-right
+   #:yg-node-layout-get-bottom
+   #:yg-node-is-dirty
+   #:yg-node-mark-dirty
+   ;; style direction & flex
+   #:yg-node-style-set-direction
+   #:yg-node-style-set-flex-direction
+   #:yg-node-style-set-justify-content
+   #:yg-node-style-set-align-items
+   #:yg-node-style-set-align-self
+   #:yg-node-style-set-align-content
+   #:yg-node-style-set-flex-wrap
+   #:yg-node-style-set-position-type
+   #:yg-node-style-set-flex-grow
+   #:yg-node-style-set-flex-shrink
+   #:yg-node-style-set-flex-basis
+   #:yg-node-style-set-flex-basis-auto
+   #:yg-node-style-set-flex-basis-percent
+   #:yg-node-style-set-overflow
+   #:yg-node-style-set-display
+   ;; style dimensions
+   #:yg-node-style-set-width
+   #:yg-node-style-set-width-percent
+   #:yg-node-style-set-width-auto
+   #:yg-node-style-set-height
+   #:yg-node-style-set-height-percent
+   #:yg-node-style-set-height-auto
+   #:yg-node-style-set-min-width
+   #:yg-node-style-set-min-width-percent
+   #:yg-node-style-set-min-height
+   #:yg-node-style-set-min-height-percent
+   #:yg-node-style-set-max-width
+   #:yg-node-style-set-max-height
+   #:yg-node-style-set-aspect-ratio
+   ;; style padding/margin/border/gap/position
+   #:yg-node-style-set-padding
+   #:yg-node-style-set-padding-percent
+   #:yg-node-style-set-margin
+   #:yg-node-style-set-margin-percent
+   #:yg-node-style-set-margin-auto
+   #:yg-node-style-set-border
+   #:yg-node-style-set-gap
+   #:yg-node-style-set-position
+   #:yg-node-style-set-position-percent
+   ;; style getters
+   #:yg-node-style-get-width
+   #:yg-node-style-get-height
+   #:yg-node-style-get-flex-direction
+   #:yg-node-style-get-align-items
+   #:yg-node-style-get-justify-content))
+
+(in-package :cl-tui.yoga-ffi)
+#+end_src
+
+
+* Foreign Library Loading
+
+#+begin_src lisp
+(defparameter *libyoga* nil "Handle for the loaded Yoga shared library.")
+
+(defun load-yoga ()
+  "Load the Yoga shared library via CFFI."
+  (setf *libyoga* (cffi:load-foreign-library "/usr/local/lib/libyoga.so"))
+  (sb-int:set-floating-point-modes :traps '())
+  *libyoga*)
+
+(load-yoga)
+#+end_src
+
+* Enum Constants
+
+#+begin_src lisp
+(eval-when (:compile-toplevel :load-toplevel :execute)
+  ;; YGDirection
+  (defconstant +yg-direction-inherit+ 0)
+  (defconstant +yg-direction-ltr+ 1)
+  (defconstant +yg-direction-rtl+ 2)
+  ;; YGFlexDirection
+  (defconstant +yg-flex-direction-column+ 0)
+  (defconstant +yg-flex-direction-column-reverse+ 1)
+  (defconstant +yg-flex-direction-row+ 2)
+  (defconstant +yg-flex-direction-row-reverse+ 3)
+  ;; YGJustify
+  (defconstant +yg-justify-auto+ 0)
+  (defconstant +yg-justify-flex-start+ 1)
+  (defconstant +yg-justify-center+ 2)
+  (defconstant +yg-justify-flex-end+ 3)
+  (defconstant +yg-justify-space-between+ 4)
+  (defconstant +yg-justify-space-around+ 5)
+  (defconstant +yg-justify-space-evenly+ 6)
+  (defconstant +yg-justify-stretch+ 7)
+  ;; YGAlign
+  (defconstant +yg-align-auto+ 0)
+  (defconstant +yg-align-flex-start+ 1)
+  (defconstant +yg-align-center+ 2)
+  (defconstant +yg-align-flex-end+ 3)
+  (defconstant +yg-align-stretch+ 4)
+  (defconstant +yg-align-baseline+ 5)
+  (defconstant +yg-align-space-between+ 6)
+  (defconstant +yg-align-space-around+ 7)
+  (defconstant +yg-align-space-evenly+ 8)
+  ;; YGWrap
+  (defconstant +yg-wrap-nowrap+ 0)
+  (defconstant +yg-wrap-wrap+ 1)
+  (defconstant +yg-wrap-wrap-reverse+ 2)
+  ;; YGPositionType
+  (defconstant +yg-position-type-static+ 0)
+  (defconstant +yg-position-type-relative+ 1)
+  (defconstant +yg-position-type-absolute+ 2)
+  ;; YGOverflow
+  (defconstant +yg-overflow-visible+ 0)
+  (defconstant +yg-overflow-hidden+ 1)
+  (defconstant +yg-overflow-scroll+ 2)
+  ;; YGDisplay
+  (defconstant +yg-display-flex+ 0)
+  (defconstant +yg-display-none+ 1)
+  (defconstant +yg-display-contents+ 2)
+  ;; YGEdge
+  (defconstant +yg-edge-left+ 0)
+  (defconstant +yg-edge-top+ 1)
+  (defconstant +yg-edge-right+ 2)
+  (defconstant +yg-edge-bottom+ 3)
+  (defconstant +yg-edge-start+ 4)
+  (defconstant +yg-edge-end+ 5)
+  (defconstant +yg-edge-horizontal+ 6)
+  (defconstant +yg-edge-vertical+ 7)
+  (defconstant +yg-edge-all+ 8)
+  ;; YGGutter
+  (defconstant +yg-gutter-column+ 0)
+  (defconstant +yg-gutter-row+ 1)
+  (defconstant +yg-gutter-all+ 2)
+  ;; YGUnit
+  (defconstant +yg-unit-undefined+ 0)
+  (defconstant +yg-unit-point+ 1)
+  (defconstant +yg-unit-percent+ 2)
+  (defconstant +yg-unit-auto+ 3))
+#+end_src
+
+* CFFI Foreign Type Definitions
+
+#+begin_src lisp
+(cffi:defctype yg-node-ref :pointer)
+(cffi:defctype yg-node-const-ref :pointer)
+
+(cffi:defcstruct yg-size
+  (width :float)
+  (height :float))
+
+(cffi:defcstruct yg-value
+  (value :float)
+  (unit :int))
+#+end_src
+
+* Node Management
+
+#+begin_src lisp
+(cffi:defcfun ("YGNodeNew" yg-node-new) yg-node-ref)
+
+(cffi:defcfun ("YGNodeFree" yg-node-free) :void
+  (node yg-node-ref))
+
+(cffi:defcfun ("YGNodeFreeRecursive" yg-node-free-recursive) :void
+  (node yg-node-ref))
+
+(cffi:defcfun ("YGNodeInsertChild" yg-node-insert-child) :void
+  (node yg-node-ref)
+  (child yg-node-ref)
+  (index :unsigned-int))
+
+(cffi:defcfun ("YGNodeRemoveChild" yg-node-remove-child) :void
+  (node yg-node-ref)
+  (child yg-node-ref))
+
+(cffi:defcfun ("YGNodeRemoveAllChildren" yg-node-remove-all-children) :void
+  (node yg-node-ref))
+
+(cffi:defcfun ("YGNodeGetChildCount" yg-node-get-child-count) :unsigned-int
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeGetChild" yg-node-get-child) yg-node-ref
+  (node yg-node-ref)
+  (index :unsigned-int))
+#+end_src
+
+* Layout Calculation
+
+#+begin_src lisp
+(cffi:defcfun ("YGNodeCalculateLayout" yg-node-calculate-layout) :void
+  (node yg-node-ref)
+  (available-width :float)
+  (available-height :float)
+  (owner-direction :int))
+
+(cffi:defcfun ("YGNodeLayoutGetLeft" yg-node-layout-get-left) :float
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeLayoutGetTop" yg-node-layout-get-top) :float
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeLayoutGetWidth" yg-node-layout-get-width) :float
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeLayoutGetHeight" yg-node-layout-get-height) :float
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeLayoutGetRight" yg-node-layout-get-right) :float
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeLayoutGetBottom" yg-node-layout-get-bottom) :float
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeIsDirty" yg-node-is-dirty) :boolean
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeMarkDirty" yg-node-mark-dirty) :void
+  (node yg-node-ref))
+#+end_src
+
+* Style Setters — Direction and Flex
+
+#+begin_src lisp
+(cffi:defcfun ("YGNodeStyleSetDirection" yg-node-style-set-direction) :void
+  (node yg-node-ref)
+  (direction :int))
+
+(cffi:defcfun ("YGNodeStyleSetFlexDirection" yg-node-style-set-flex-direction) :void
+  (node yg-node-ref)
+  (flex-direction :int))
+
+(cffi:defcfun ("YGNodeStyleSetJustifyContent" yg-node-style-set-justify-content) :void
+  (node yg-node-ref)
+  (justify :int))
+
+(cffi:defcfun ("YGNodeStyleSetAlignItems" yg-node-style-set-align-items) :void
+  (node yg-node-ref)
+  (align :int))
+
+(cffi:defcfun ("YGNodeStyleSetAlignSelf" yg-node-style-set-align-self) :void
+  (node yg-node-ref)
+  (align :int))
+
+(cffi:defcfun ("YGNodeStyleSetAlignContent" yg-node-style-set-align-content) :void
+  (node yg-node-ref)
+  (align :int))
+
+(cffi:defcfun ("YGNodeStyleSetFlexWrap" yg-node-style-set-flex-wrap) :void
+  (node yg-node-ref)
+  (wrap :int))
+
+(cffi:defcfun ("YGNodeStyleSetPositionType" yg-node-style-set-position-type) :void
+  (node yg-node-ref)
+  (position-type :int))
+
+(cffi:defcfun ("YGNodeStyleSetFlexGrow" yg-node-style-set-flex-grow) :void
+  (node yg-node-ref)
+  (flex-grow :float))
+
+(cffi:defcfun ("YGNodeStyleSetFlexShrink" yg-node-style-set-flex-shrink) :void
+  (node yg-node-ref)
+  (flex-shrink :float))
+
+(cffi:defcfun ("YGNodeStyleSetFlexBasis" yg-node-style-set-flex-basis) :void
+  (node yg-node-ref)
+  (flex-basis :float))
+
+(cffi:defcfun ("YGNodeStyleSetFlexBasisAuto" yg-node-style-set-flex-basis-auto) :void
+  (node yg-node-ref))
+
+(cffi:defcfun ("YGNodeStyleSetFlexBasisPercent" yg-node-style-set-flex-basis-percent) :void
+  (node yg-node-ref)
+  (flex-basis :float))
+
+(cffi:defcfun ("YGNodeStyleSetOverflow" yg-node-style-set-overflow) :void
+  (node yg-node-ref)
+  (overflow :int))
+
+(cffi:defcfun ("YGNodeStyleSetDisplay" yg-node-style-set-display) :void
+  (node yg-node-ref)
+  (display :int))
+#+end_src
+
+* Style Setters — Dimensions
+
+#+begin_src lisp
+(cffi:defcfun ("YGNodeStyleSetWidth" yg-node-style-set-width) :void
+  (node yg-node-ref)
+  (width :float))
+
+(cffi:defcfun ("YGNodeStyleSetWidthPercent" yg-node-style-set-width-percent) :void
+  (node yg-node-ref)
+  (width :float))
+
+(cffi:defcfun ("YGNodeStyleSetWidthAuto" yg-node-style-set-width-auto) :void
+  (node yg-node-ref))
+
+(cffi:defcfun ("YGNodeStyleSetHeight" yg-node-style-set-height) :void
+  (node yg-node-ref)
+  (height :float))
+
+(cffi:defcfun ("YGNodeStyleSetHeightPercent" yg-node-style-set-height-percent) :void
+  (node yg-node-ref)
+  (height :float))
+
+(cffi:defcfun ("YGNodeStyleSetHeightAuto" yg-node-style-set-height-auto) :void
+  (node yg-node-ref))
+
+(cffi:defcfun ("YGNodeStyleSetMinWidth" yg-node-style-set-min-width) :void
+  (node yg-node-ref)
+  (min-width :float))
+
+(cffi:defcfun ("YGNodeStyleSetMinWidthPercent" yg-node-style-set-min-width-percent) :void
+  (node yg-node-ref)
+  (min-width :float))
+
+(cffi:defcfun ("YGNodeStyleSetMinHeight" yg-node-style-set-min-height) :void
+  (node yg-node-ref)
+  (min-height :float))
+
+(cffi:defcfun ("YGNodeStyleSetMinHeightPercent" yg-node-style-set-min-height-percent) :void
+  (node yg-node-ref)
+  (min-height :float))
+
+(cffi:defcfun ("YGNodeStyleSetMaxWidth" yg-node-style-set-max-width) :void
+  (node yg-node-ref)
+  (max-width :float))
+
+(cffi:defcfun ("YGNodeStyleSetMaxHeight" yg-node-style-set-max-height) :void
+  (node yg-node-ref)
+  (max-height :float))
+
+(cffi:defcfun ("YGNodeStyleSetAspectRatio" yg-node-style-set-aspect-ratio) :void
+  (node yg-node-ref)
+  (aspect-ratio :float))
+#+end_src
+
+* Style Setters — Padding, Margin, Border, Gap, Position
+
+#+begin_src lisp
+(cffi:defcfun ("YGNodeStyleSetPadding" yg-node-style-set-padding) :void
+  (node yg-node-ref)
+  (edge :int)
+  (padding :float))
+
+(cffi:defcfun ("YGNodeStyleSetPaddingPercent" yg-node-style-set-padding-percent) :void
+  (node yg-node-ref)
+  (edge :int)
+  (padding :float))
+
+(cffi:defcfun ("YGNodeStyleSetMargin" yg-node-style-set-margin) :void
+  (node yg-node-ref)
+  (edge :int)
+  (margin :float))
+
+(cffi:defcfun ("YGNodeStyleSetMarginPercent" yg-node-style-set-margin-percent) :void
+  (node yg-node-ref)
+  (edge :int)
+  (margin :float))
+
+(cffi:defcfun ("YGNodeStyleSetMarginAuto" yg-node-style-set-margin-auto) :void
+  (node yg-node-ref)
+  (edge :int))
+
+(cffi:defcfun ("YGNodeStyleSetBorder" yg-node-style-set-border) :void
+  (node yg-node-ref)
+  (edge :int)
+  (border :float))
+
+(cffi:defcfun ("YGNodeStyleSetGap" yg-node-style-set-gap) :void
+  (node yg-node-ref)
+  (gutter :int)
+  (gap :float))
+
+(cffi:defcfun ("YGNodeStyleSetPosition" yg-node-style-set-position) :void
+  (node yg-node-ref)
+  (edge :int)
+  (position :float))
+
+(cffi:defcfun ("YGNodeStyleSetPositionPercent" yg-node-style-set-position-percent) :void
+  (node yg-node-ref)
+  (edge :int)
+  (position :float))
+#+end_src
+
+* Style Getters
+
+#+begin_src lisp
+(cffi:defcfun ("YGNodeStyleGetWidth" yg-node-style-get-width) yg-value
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeStyleGetHeight" yg-node-style-get-height) yg-value
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeStyleGetFlexDirection" yg-node-style-get-flex-direction) :int
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeStyleGetAlignItems" yg-node-style-get-align-items) :int
+  (node yg-node-const-ref))
+
+(cffi:defcfun ("YGNodeStyleGetJustifyContent" yg-node-style-get-justify-content) :int
+  (node yg-node-const-ref))
+#+end_src
+
+* Test Suite
+
+#+begin_src lisp
+(eval-when (:compile-toplevel :load-toplevel :execute)
+  (ql:quickload :fiveam :silent t))
+
+(defpackage :cl-tui.yoga-ffi-tests
+  (:use :cl :fiveam)
+  (:import-from :cl-tui.yoga-ffi
+   #:load-yoga
+   #:yg-node-new
+   #:yg-node-free
+   #:yg-node-free-recursive
+   #:yg-node-insert-child
+   #:yg-node-get-child-count
+   #:yg-node-calculate-layout
+   #:yg-node-layout-get-left
+   #:yg-node-layout-get-top
+   #:yg-node-layout-get-width
+   #:yg-node-layout-get-height
+   #:yg-node-style-set-flex-direction
+   #:yg-node-style-set-justify-content
+   #:yg-node-style-set-align-items
+   #:yg-node-style-set-width
+   #:yg-node-style-set-height
+   #:yg-node-style-set-padding
+   #:yg-node-style-set-margin
+   #:yg-node-style-set-flex-grow
+   #:yg-node-style-set-position-type
+   #:yg-node-style-set-position
+   #:+yg-flex-direction-column+
+   #:+yg-flex-direction-row+
+   #:+yg-justify-center+
+   #:+yg-justify-flex-start+
+   #:+yg-align-stretch+
+   #:+yg-align-center+
+   #:+yg-edge-all+
+   #:+yg-edge-left+
+   #:+yg-edge-top+
+   #:+yg-edge-right+
+   #:+yg-edge-bottom+
+   #:+yg-position-type-relative+
+   #:+yg-position-type-absolute+
+   ;; YGDirection constants (different from YGFlexDirection!)
+   #:+yg-direction-inherit+
+   #:+yg-direction-ltr+
+   #:+yg-direction-rtl+))
+
+(in-package :cl-tui.yoga-ffi-tests)
+
+(fiveam:def-suite yoga-ffi-suite
+  :description "Yoga FFI binding verification")
+(fiveam:in-suite yoga-ffi-suite)
+
+(fiveam:test test-node-create-free
+  "Contract: yg-node-new returns a non-null pointer; yg-node-free doesn't crash."
+  (let ((node (yg-node-new)))
+    (fiveam:is (not (cffi:null-pointer-p node)))
+    (yg-node-free node)
+    (fiveam:pass)))
+
+(fiveam:test test-node-child-count
+  "Contract: yg-node-get-child-count returns 0 for a new node."
+  (let ((node (yg-node-new)))
+    (fiveam:is (= 0 (yg-node-get-child-count node)))
+    (yg-node-free node)))
+
+(fiveam:test test-node-insert-child
+  "Contract: inserting a child increments the child count."
+  (let ((parent (yg-node-new))
+        (child (yg-node-new)))
+    (yg-node-insert-child parent child 0)
+    (fiveam:is (= 1 (yg-node-get-child-count parent)))
+    (yg-node-free-recursive parent)))
+
+(fiveam:test test-layout-basic-column
+  "Contract: a column with two fixed-height children positions them vertically."
+  (let* ((root (yg-node-new)))
+    (yg-node-style-set-width root 100.0)
+    (yg-node-style-set-height root 200.0)
+    (yg-node-style-set-flex-direction root +yg-flex-direction-column+)
+    (let ((child1 (yg-node-new))
+          (child2 (yg-node-new)))
+      (yg-node-style-set-width child1 100.0)
+      (yg-node-style-set-height child1 50.0)
+      (yg-node-style-set-width child2 100.0)
+      (yg-node-style-set-height child2 50.0)
+      (yg-node-insert-child root child1 0)
+      (yg-node-insert-child root child2 1)
+      (yg-node-calculate-layout root 100.0 200.0 +yg-direction-ltr+)
+      (fiveam:is (= 0.0 (yg-node-layout-get-left child1)))
+      (fiveam:is (= 0.0 (yg-node-layout-get-top child1)))
+      (fiveam:is (= 50.0 (yg-node-layout-get-top child2)))
+      (yg-node-free-recursive root))))
+
+(fiveam:test test-layout-basic-row
+  "Contract: a row with two fixed-width children positions them horizontally."
+  (let* ((root (yg-node-new)))
+    (yg-node-style-set-width root 200.0)
+    (yg-node-style-set-height root 100.0)
+    (yg-node-style-set-flex-direction root +yg-flex-direction-row+)
+    (let ((child1 (yg-node-new))
+          (child2 (yg-node-new)))
+      (yg-node-style-set-width child1 80.0)
+      (yg-node-style-set-height child1 50.0)
+      (yg-node-style-set-width child2 80.0)
+      (yg-node-style-set-height child2 50.0)
+      (yg-node-insert-child root child1 0)
+      (yg-node-insert-child root child2 1)
+      (yg-node-calculate-layout root 200.0 100.0 +yg-direction-ltr+)
+      (fiveam:is (= 0.0 (yg-node-layout-get-left child1)))
+      (fiveam:is (= 0.0 (yg-node-layout-get-top child1)))
+      (fiveam:is (= 80.0 (yg-node-layout-get-left child2)))
+      (yg-node-free-recursive root))))
+
+(fiveam:test test-layout-flex-grow
+  "Contract: flex-grow distributes remaining space proportionally."
+  (let* ((root (yg-node-new)))
+    (yg-node-style-set-width root 200.0)
+    (yg-node-style-set-height root 100.0)
+    (yg-node-style-set-flex-direction root +yg-flex-direction-row+)
+    (let ((child1 (yg-node-new))
+          (child2 (yg-node-new)))
+      (yg-node-style-set-height child1 100.0)
+      (yg-node-style-set-flex-grow child1 1.0)
+      (yg-node-style-set-height child2 100.0)
+      (yg-node-style-set-flex-grow child2 2.0)
+      (yg-node-insert-child root child1 0)
+      (yg-node-insert-child root child2 1)
+      (yg-node-calculate-layout root 200.0 100.0 +yg-direction-ltr+)
+      (fiveam:is (< 0.0 (yg-node-layout-get-width child1)))
+      (fiveam:is (< 0.0 (yg-node-layout-get-width child2)))
+      (fiveam:is (= 200.0 (+ (yg-node-layout-get-width child1)
+                             (yg-node-layout-get-width child2))))
+      (yg-node-free-recursive root))))
+
+(fiveam:test test-layout-absolute-position
+  "Contract: an absolute child positions relative to its parent."
+  (let* ((root (yg-node-new)))
+    (yg-node-style-set-width root 300.0)
+    (yg-node-style-set-height root 300.0)
+    (let ((child (yg-node-new)))
+      (yg-node-style-set-width child 50.0)
+      (yg-node-style-set-height child 50.0)
+      (yg-node-style-set-position-type child +yg-position-type-absolute+)
+      (yg-node-style-set-position child +yg-edge-left+ 100.0)
+      (yg-node-style-set-position child +yg-edge-top+ 50.0)
+      (yg-node-insert-child root child 0)
+      (yg-node-calculate-layout root 300.0 300.0 +yg-direction-ltr+)
+      (fiveam:is (= 100.0 (yg-node-layout-get-left child)))
+      (fiveam:is (= 50.0 (yg-node-layout-get-top child)))
+      (fiveam:is (= 50.0 (yg-node-layout-get-width child)))
+      (fiveam:is (= 50.0 (yg-node-layout-get-height child)))
+      (yg-node-free-recursive root))))
+
+(fiveam:test test-layout-padding
+  "Contract: padding reduces the available space for children."
+  (let* ((root (yg-node-new)))
+    (yg-node-style-set-width root 200.0)
+    (yg-node-style-set-height root 100.0)
+    (yg-node-style-set-padding root +yg-edge-all+ 10.0)
+    (let ((child (yg-node-new)))
+      (yg-node-style-set-width child 180.0)
+      (yg-node-style-set-height child 80.0)
+      (yg-node-insert-child root child 0)
+      (yg-node-calculate-layout root 200.0 100.0 +yg-direction-ltr+)
+      (fiveam:is (= 10.0 (yg-node-layout-get-left child)))
+      (fiveam:is (= 10.0 (yg-node-layout-get-top child)))
+      (yg-node-free-recursive root))))
+
+(fiveam:test test-layout-nested
+  "Contract: nested containers produce correct leaf positions."
+  (let* ((root (yg-node-new)))
+    (yg-node-style-set-width root 400.0)
+    (yg-node-style-set-height root 400.0)
+    (yg-node-style-set-flex-direction root +yg-flex-direction-column+)
+    (let ((outer (yg-node-new)))
+      (yg-node-style-set-width outer 400.0)
+      (yg-node-style-set-height outer 200.0)
+      (yg-node-style-set-flex-direction outer +yg-flex-direction-row+)
+      (let ((inner (yg-node-new)))
+        (yg-node-style-set-width inner 100.0)
+        (yg-node-style-set-height inner 100.0)
+        (yg-node-insert-child outer inner 0)
+        (yg-node-insert-child root outer 0)
+        (yg-node-calculate-layout root 400.0 400.0 +yg-direction-ltr+)
+        (fiveam:is (= 0.0 (yg-node-layout-get-left inner)))
+        (fiveam:is (= 100.0 (yg-node-layout-get-width inner)))
+        (fiveam:is (= 100.0 (yg-node-layout-get-height inner)))
+        (yg-node-free-recursive root)))))
+#+end_src