feat(lib): add doom-copy

For deep-copying. Necessary for coming changes.

lisp/doom-lib.el

@@ -325,6 +325,49 @@ TRIGGER-HOOK is a list of quoted hooks and/or sharp-quoted functions."
                   (put 'doom-compile-function 'timer nil))))))
 
 
+;;
+;;; Deep copying
+
+(cl-defgeneric doom-copy (val &optional _deep?)
+  "Return a (optionally deep) copy of VAL."
+  (cl-check-type val (or integer float boolean symbol null))
+  val)
+
+(cl-defmethod doom-copy ((val record) &optional deep?)
+  "Return a (optionally deep) copy of record VAL."
+  (if deep?
+      (cl-loop with newval = (copy-sequence val)
+               for idx from 1 to (length (cdr (cl-struct-slot-info (type-of val))))
+               do (aset newval idx (doom-copy (aref newval idx) t))
+               finally return newval)
+    (copy-sequence val)))
+
+(cl-defmethod doom-copy ((val sequence) &optional deep?)
+  "Return a (optionally deep) copy of sequence VAL."
+  (if (stringp val)
+      (if deep? val (purecopy val))
+    (if deep?
+        (when-let ((newval (mapcar (doom-rpartial #'doom-copy t) val)))
+          (if (vectorp val)
+              (apply #'vector newval)
+            newval))
+      (copy-sequence val))))
+
+(cl-defmethod doom-copy ((val cons) &optional deep?)
+  "Return a (optionally deep) copy of cons cell/list VAL."
+  (cons (doom-copy (car val) deep?)
+        (doom-copy (cdr val) deep?)))
+
+(cl-defmethod doom-copy ((val hash-table) &optional deep?)
+  "Return a (optionally deep) copy of hash table VAL."
+  (let ((table (copy-hash-table val)))
+    (when deep?
+      (maphash (lambda (key val)
+                 (puthash key (doom-copy val t) table))
+               table))
+    table))
+
+
 ;;
 ;;; Sugars