From b1e6b624739552c19cd4c3b033716360fda64e94 Mon Sep 17 00:00:00 2001
From: plugd <plugd@thelambdalab.xyz>
Date: Thu, 18 Nov 2021 10:46:21 +0100
Subject: [PATCH] Added object removal/insertion operations.

---
 ez.el | 90 ++++++++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 67 insertions(+), 23 deletions(-)

diff --git a/ez.el b/ez.el
index 8ebed7b..1efc2d6 100644
--- a/ez.el
+++ b/ez.el
@@ -120,21 +120,33 @@
   (dotimes (i 31)
     (aset ez-property-defaults i (aref ez-memory (+ ez-objtab-addr (* 2 i))))))
 
-(defun ez-get-obj-addr (obj-id)
-  (+ ez-objtab-addr (* 2 31) (* 9 (- obj-id 1))))
+(defun ez-get-obj-addr (obj)
+  (+ ez-objtab-addr (* 2 31) (* 9 (- obj 1))))
 
-(defun ez-get-obj-parent (obj-id)
-  (let ((addr (ez-get-obj-addr obj-id)))
+(defun ez-get-obj-parent (obj)
+  (let ((addr (ez-get-obj-addr obj)))
     (ez-mem-ref-byte (+ addr 4))))
 
-(defun ez-get-obj-sibling (obj-id)
-  (let ((addr (ez-get-obj-addr obj-id)))
+(defun ez-set-obj-parent (obj new-parent)
+  (let ((addr (ez-get-obj-addr obj)))
+    (ez-mem-set-byte (+ addr 4) new-parent)))
+
+(defun ez-get-obj-sibling (obj)
+  (let ((addr (ez-get-obj-addr obj)))
     (ez-mem-ref-byte (+ addr 5))))
 
-(defun ez-get-obj-child (obj-id)
-  (let ((addr (ez-get-obj-addr obj-id)))
+(defun ez-set-obj-sibling (obj new-sibling)
+  (let ((addr (ez-get-obj-addr obj)))
+    (ez-mem-set-byte (+ addr 5) new-sibling)))
+
+(defun ez-get-obj-child (obj)
+  (let ((addr (ez-get-obj-addr obj)))
     (ez-mem-ref-byte (+ addr 6))))
 
+(defun ez-set-obj-child (obj new-child)
+  (let ((addr (ez-get-obj-addr obj)))
+    (ez-mem-set-byte (+ addr 6) new-child)))
+
 (defun ez-get-obj-plist-addr (obj-id)
   (let ((addr (ez-get-obj-addr obj-id)))
     (ez-mem-ref-word (+ addr 7))))
@@ -145,21 +157,6 @@
         (ez-get-zstring (+ 1 (ez-get-obj-plist-addr obj-id)))
       nil)))
 
-(defun ez-get-obj (obj-id)
-  (let ((addr (+ ez-objtab-addr
-                 (* 2 31)
-                 (* 9 (- obj-id 1)))))
-    (list
-     obj-id
-     (ez-mem-ref-byte (+ addr 4))
-     (ez-mem-ref-byte (+ addr 5))
-     (ez-mem-ref-byte (+ addr 6))
-     (ez-mem-ref-word (+ addr 7))
-     (let ((plist-addr (ez-mem-ref-word (+ addr 7))))
-       (if (> (ez-mem-ref-byte plist-addr) 0)
-           (ez-get-zstring (+ 1 plist-addr))
-         nil)))))
-
 (defun ez-get-prop-default (prop)
   (ez-mem-ref-word (+ ez-objtab-addr (* 2 (+ 1 prop)))))
 
@@ -222,6 +219,26 @@
             (and (not current-set) (> val 0)))
         (ez-mem-set-byte byte-addr (logxor byte bit-mask)))))
 
+
+(defun ez-remove-obj (obj)
+  (let ((parent (ez-get-obj-parent obj))
+        (sibling (ez-get-obj-sibling obj)))
+    (unless (= parent 0)
+      (let ((child (ez-get-obj-child parent)))
+        (if (= child obj)
+            (ez-set-obj-child parent sibling)
+          (while (not (= obj (ez-get-obj-sibling child)))
+            (setq child (ez-get-obj-sibling child)))
+          (ez-set-obj-sibling child (ez-get-obj-sibling obj))))
+      (ez-set-obj-parent obj 0))
+    (ez-set-obj-sibling obj 0)))
+
+(defun ez-insert-obj (obj new-parent)
+  (ez-remove-obj obj)
+  (unless (= new-parent 0)
+    (ez-set-obj-sibling obj (ez-get-obj-child new-parent))
+    (ez-set-obj-child new-parent obj)))
+
 ;; Z-strings
 
 (defvar ez-zstring-alphabets
@@ -522,6 +539,10 @@
     ((1op #x02) get_child ez-op-get-child)
     ((1op #x03) get_parent ez-op-get-parent)
     ((2op #x0A) test_attr ez-op-test-attr)
+    ((2op #x0B) set_attr ez-op-set-attr)
+    ((2op #x0C) clear_attr ez-op-clear-attr)
+    ((1op #x09) remove_obj ez-op-remove-obj)
+    ((2op #x0E) insert_obj ez-op-insert-obj)
     ((var #x03) put_prop ez-op-put-prop)
     ((0op #x02) print ez-op-print)
     ((0op #x0B) new_line ez-op-new-line)
@@ -685,6 +706,18 @@
     (ez-do-branch (= 1 (ez-get-obj-attr obj attr)))
     t))
 
+(defun ez-op-set-attr (operands operand-types)
+  (let ((obj (car operands))
+        (attr (cadr operands)))
+    (ez-set-obj-attr obj attr 1))
+  t)
+
+(defun ez-op-clear-attr (operands operand-types)
+  (let ((obj (car operands))
+        (attr (cadr operands)))
+    (ez-set-obj-attr obj attr 0))
+  t)
+
 (defun ez-op-get-sibling (operands operand-types)
   (let ((sib (ez-get-obj-sibling (car operands))))
     (ez-set-var (ez-read-pc-byte-and-inc) sib)
@@ -703,6 +736,17 @@
     (ez-do-branch (> parent 0))
     t))
 
+(defun ez-op-remove-obj (operands operand-types)
+  (let ((obj (car operands)))
+    (ez-remove-obj obj))
+  t)
+
+(defun ez-op-insert-obj (operands operand-types)
+  (let ((obj1 (car operands))
+        (obj2 (cadr operands)))
+    (ez-insert-obj obj1 obj2))
+  t)
+
 (defun ez-op-put-prop (operands operand-types)
   (let* ((obj (car operands))
          (prop (cadr operands))
-- 
2.20.1