ob: Replace angle brackets with parenthesis in Babel hashes

* lisp/ob-core.el (org-babel-hash-show-time): Remove
unnecessary :version keyword.
(org-babel-result-regexp):
(org-babel--insert-results-keyword): Remove angle brackets from time
stamp in hash.
* testing/lisp/test-ob.el (test-ob/where-is-src-block-result): Update
test.

Reported-by: stardiviner <numbchild@gmail.com>
<http://lists.gnu.org/r/emacs-orgmode/2020-05/msg00198.html>

lisp/ob-core.el

@@ -165,7 +165,6 @@ This string must include a \"%s\" which will be replaced by the results."
   "Non-nil means show the time the code block was evaluated in the result hash."
   :group 'org-babel
   :type 'boolean
-  :version "26.1"
   :package-version '(Org . "9.0")
   :safe #'booleanp)
 
@@ -488,11 +487,21 @@ For the format of SAFE-LIST, see `org-babel-safe-header-args'."
   "Regexp matching a NAME keyword.")
 
 (defconst org-babel-result-regexp
-  (format "^[ \t]*#\\+%s\\(?:\\[\\(?:%s \\)?\\([[:alnum:]]+\\)\\]\\)?:[ \t]*"
-	  org-babel-results-keyword
-	  ;; <%Y-%m-%d %H:%M:%S>
-	  "<\\(?:[0-9]\\{4\\}-[0-1][0-9]-[0-3][0-9] \
-[0-2][0-9]\\(?::[0-5][0-9]\\)\\{2\\}\\)>")
+  (rx (seq bol
+           (zero-or-more (any "\t "))
+           "#+results"
+           (opt "["
+		;; Time stamp part.
+		(opt "("
+                     (= 4 digit) (= 2 "-" (= 2 digit))
+                     " "
+                     (= 2 digit) (= 2 ":" (= 2 digit))
+                     ") ")
+		;; SHA1 hash.
+		(group (one-or-more hex-digit))
+		"]")
+           ":"
+           (zero-or-more (any "\t "))))
   "Regular expression used to match result lines.
 If the results are associated with a hash key then the hash will
 be saved in match group 1.")
@@ -1940,7 +1949,7 @@ the results hash, or nil.  Leave point before the keyword."
 		  (cond ((not hash) nil)
 			(org-babel-hash-show-time
 			 (format "[%s %s]"
-				 (format-time-string "<%F %T>")
+				 (format-time-string "(%F %T)")
 				 hash))
 			(t (format "[%s]" hash)))
 		  ":"

testing/lisp/test-ob.el

@@ -2090,34 +2090,33 @@ default-directory
   ;; Handle hashes with times.
   (should
    (equal
-    "#+RESULTS[<2014-03-04 00:41:10> bbbb]:"
+    "#+RESULTS[(2014-03-04 00:41:10) bbbb]:"
     (org-test-with-temp-text
-	"
-<point>#+BEGIN_SRC emacs-lisp
+	"#+BEGIN_SRC emacs-lisp
 \(+ 1 1)
 #+END_SRC
 
-#+RESULTS[<2012-03-29 16:40:12> aaaa]:"
+#+RESULTS[(2012-03-29 16:40:12) aaaa]:"
       (let ((org-babel-results-keyword "RESULTS")
 	    (org-babel-hash-show-time t))
 	(cl-letf (((symbol-function 'format-time-string)
-		   (lambda (&rest _) "<2014-03-04 00:41:10>")))
+		   (lambda (&rest _) "(2014-03-04 00:41:10)")))
 	  (goto-char (org-babel-where-is-src-block-result nil nil "bbbb"))
 	  (org-trim (buffer-substring-no-properties (point) (point-max))))))))
   (should
    (equal
-    "#+RESULTS[<2012-03-29 16:40:12> aaaa]:"
+    "#+RESULTS[(2012-03-29 16:40:12) aaaa]:"
     (org-test-with-temp-text
 	"
 <point>#+BEGIN_SRC emacs-lisp
 \(+ 1 1)
 #+END_SRC
 
-#+RESULTS[<2012-03-29 16:40:12> aaaa]:"
+#+RESULTS[(2012-03-29 16:40:12) aaaa]:"
       (let ((org-babel-results-keyword "RESULTS")
 	    (org-babel-hash-show-time t))
 	(cl-letf (((symbol-function 'format-time-string)
-		   (lambda (&rest _) "<2014-03-04 00:41:10>")))
+		   (lambda (&rest _) "(2014-03-04 00:41:10)")))
 	  (goto-char (org-babel-where-is-src-block-result nil nil "aaaa"))
 	  (org-trim (buffer-substring-no-properties (point) (point-max))))))))
   ;; RESULTS keyword may not be the last affiliated keyword.