org-element: Interpret pseudo objects without declaration

* lisp/org-element.el (org-element-object-containers): New variable
(org-element-interpret-data): Remove optional argument.
(org-element--interpret-data-1): Remove optional argument.  Guess when
a given element or object has a pseudo type.

* lisp/ox-latex.el (org-latex-pseudo-objects): Remove variable.
(org-latex-table, org-latex--math-table): Apply signature change above.

* testing/lisp/test-org-element.el (test-org-element/interpret-data):
  Update test.

lisp/org-element.el

@@ -249,6 +249,10 @@ specially in `org-element--object-lex'.")
 	 superscript table-cell underline)
   "List of recursive object types.")
 
+(defconst org-element-object-containers
+  (append org-element-recursive-objects '(paragraph table-row verse-block))
+  "List of object or element types that can directly contain objects.")
+
 (defvar org-element-block-name-alist
   '(("CENTER" . org-element-center-block-parser)
     ("COMMENT" . org-element-comment-block-parser)
@@ -4353,30 +4357,18 @@ the current object."
 ;; `org-element--interpret-affiliated-keywords'.
 
 ;;;###autoload
-(defun org-element-interpret-data (data &optional pseudo-objects)
+(defun org-element-interpret-data (data)
   "Interpret DATA as Org syntax.
-
 DATA is a parse tree, an element, an object or a secondary string
-to interpret.
-
-Optional argument PSEUDO-OBJECTS is a list of symbols defining
-new types that should be treated as objects.  An unknown type not
-belonging to this list is seen as a pseudo-element instead.  Both
-pseudo-objects and pseudo-elements are transparent entities, i.e.
-only their contents are interpreted.
+to interpret.  Return Org syntax as a string."
+  (org-element--interpret-data-1 data nil))
 
-Return Org syntax as a string."
-  (org-element--interpret-data-1 data nil pseudo-objects))
-
-(defun org-element--interpret-data-1 (data parent pseudo-objects)
+(defun org-element--interpret-data-1 (data parent)
   "Interpret DATA as Org syntax.
 
 DATA is a parse tree, an element, an object or a secondary string
 to interpret.  PARENT is used for recursive calls.  It contains
-the element or object containing data, or nil.  PSEUDO-OBJECTS
-are list of symbols defining new element or object types.
-Unknown types that don't belong to this list are treated as
-pseudo-elements instead.
+the element or object containing data, or nil.
 
 Return Org syntax as a string."
   (let* ((type (org-element-type data))
@@ -4391,15 +4383,11 @@ Return Org syntax as a string."
 	   ;; Secondary string.
 	   ((not type)
 	    (mapconcat
-	     (lambda (obj)
-	       (org-element--interpret-data-1 obj parent pseudo-objects))
-	     data ""))
+	     (lambda (obj) (org-element--interpret-data-1 obj parent)) data ""))
 	   ;; Full Org document.
 	   ((eq type 'org-data)
-	    (mapconcat
-	     (lambda (obj)
-	       (org-element--interpret-data-1 obj parent pseudo-objects))
-	     (org-element-contents data) ""))
+	    (mapconcat (lambda (obj) (org-element--interpret-data-1 obj parent))
+		       (org-element-contents data) ""))
 	   ;; Plain text: return it.
 	   ((stringp data) data)
 	   ;; Element or object without contents.
@@ -4409,8 +4397,7 @@ Return Org syntax as a string."
 	    (funcall interpret data
 		     ;; Recursively interpret contents.
 		     (mapconcat
-		      (lambda (obj)
-			(org-element--interpret-data-1 obj data pseudo-objects))
+		      (lambda (obj) (org-element--interpret-data-1 obj data))
 		      (org-element-contents
 		       (if (not (memq type '(paragraph verse-block)))
 			   data
@@ -4432,7 +4419,10 @@ Return Org syntax as a string."
       ;; specified, assume its value is 0.
       (let ((post-blank (or (org-element-property :post-blank data) 0)))
 	(if (or (memq type org-element-all-objects)
-		(memq type pseudo-objects))
+		(and parent
+		     (let ((type (org-element-type parent)))
+		       (or (not type)
+			   (memq type org-element-object-containers)))))
 	    (concat results (make-string post-blank ?\s))
 	  (concat
 	   (org-element--interpret-affiliated-keywords data)

lisp/ox-latex.el

@@ -206,9 +206,6 @@
 					  ("kbordermatrix" . "\\\\"))
   "Alist between matrix macros and their row ending.")
 
-(defconst org-latex-pseudo-objects '(latex-math-block)
-  "List of pseudo-object types introduced in the back-end.")
-
 
 
 ;;; User Configurable Variables
@@ -2643,8 +2640,7 @@ contextual information."
 	(format "\\begin{verbatim}\n%s\n\\end{verbatim}"
 		;; Re-create table, without affiliated keywords.
 		(org-trim (org-element-interpret-data
-			   `(table nil ,@(org-element-contents table))
-			   org-latex-pseudo-objects))))
+			   `(table nil ,@(org-element-contents table))))))
        ;; Case 2: Matrix.
        ((or (string= type "math") (string= type "inline-math"))
 	(org-latex--math-table table info))
@@ -2841,9 +2837,7 @@ This function assumes TABLE has `org' as its `:type' property and
 	       (concat
 		(mapconcat
 		 (lambda (cell)
-		   (substring
-		    (org-element-interpret-data cell org-latex-pseudo-objects)
-		    0 -1))
+		   (substring (org-element-interpret-data cell) 0 -1))
 		 (org-element-map row 'table-cell #'identity info) "&")
 		(or (cdr (assoc env org-latex-table-matrix-macros)) "\\\\")
 		"\n")))

testing/lisp/test-org-element.el

@@ -2277,10 +2277,10 @@ Outside list"
     "#+CAPTION[s1]: l1\n#+CAPTION[s2]: l2\nParagraph\n"))
   ;; Pseudo objects and elements are transparent.
   (should
-   (equal "A B\n"
-	  (org-element-interpret-data
-	   '(paragraph nil (pseudo-object (:post-blank 1) "A") "B")
-	   '(pseudo-object))))
+   (equal "A B"
+	  (org-trim
+	   (org-element-interpret-data
+	    '(paragraph nil (pseudo-object (:post-blank 1) "A") "B")))))
   (should
    (equal "A\n\nB\n"
 	  (org-element-interpret-data