org-macs.el: Move UUID related code

* org-id.el (org-id-uuid): Move to org-macs.el.

* org.el (org-uuidgen-p): Move to org-macs.el.  Expose regexp used to
match UUID.

* org-macs.el (org-uuid-regexp): Refactor `org-uuidgen-p' to expose
regexp used to match UUID.

lisp/org-id.el

@@ -399,30 +399,6 @@ So a typical ID could look like \"Org:4nd91V40HI\"."
      (t (error "Invalid `org-id-method'")))
     (concat prefix unique)))
 
-(defun org-id-uuid ()
-  "Return string with random (version 4) UUID."
-  (let ((rnd (md5 (format "%s%s%s%s%s%s%s"
-			  (random)
-			  (org-time-convert-to-list nil)
-			  (user-uid)
-			  (emacs-pid)
-			  (user-full-name)
-			  user-mail-address
-			  (recent-keys)))))
-    (format "%s-%s-4%s-%s%s-%s"
-	    (substring rnd 0 8)
-	    (substring rnd 8 12)
-	    (substring rnd 13 16)
-	    (format "%x"
-		    (logior
-		     #b10000000
-		     (logand
-		      #b10111111
-		      (string-to-number
-		       (substring rnd 16 18) 16))))
-	    (substring rnd 18 20)
-	    (substring rnd 20 32))))
-
 (defun org-id-int-to-b36-one-digit (integer)
   "Convert INTEGER between 0 and 61 into a single character 0..9, A..Z, a..z."
   (cond

lisp/org-macs.el

@@ -829,6 +829,29 @@ When NEXT is non-nil, check the next line instead."
 When NEXT is non-nil, check the next line instead."
   (org--line-empty-p 2))
 
+(defun org-id-uuid ()
+  "Return string with random (version 4) UUID."
+  (let ((rnd (md5 (format "%s%s%s%s%s%s%s"
+			  (random)
+			  (org-time-convert-to-list nil)
+			  (user-uid)
+			  (emacs-pid)
+			  (user-full-name)
+			  user-mail-address
+			  (recent-keys)))))
+    (format "%s-%s-4%s-%s%s-%s"
+	    (substring rnd 0 8)
+	    (substring rnd 8 12)
+	    (substring rnd 13 16)
+	    (format "%x"
+		    (logior
+		     #b10000000
+		     (logand
+		      #b10111111
+		      (string-to-number
+		       (substring rnd 16 18) 16))))
+	    (substring rnd 18 20)
+	    (substring rnd 20 32))))
 
 
 ;;; Motion
@@ -948,6 +971,15 @@ return nil."
   (require 'ffap)
   (and ffap-url-regexp (string-match-p ffap-url-regexp s)))
 
+(defconst org-uuid-regexp
+  "\\`[0-9a-f]\\{8\\}-[0-9a-f]\\{4\\}-[0-9a-f]\\{4\\}-[0-9a-f]\\{4\\}-[0-9a-f]\\{12\\}\\'"
+  "Regular expression matching a universal unique identifier (UUID).")
+
+(defun org-uuidgen-p (s)
+  "Is S an ID created by UUIDGEN?"
+  (string-match org-uuid-regexp (downcase s)))
+
+
 
 ;;; String manipulation
 

lisp/org.el

@@ -18457,10 +18457,6 @@ With prefix arg UNCOMPILED, load the uncompiled versions."
     (setq s (replace-match "\\vert" t t s)))
   s)
 
-(defun org-uuidgen-p (s)
-  "Is S an ID created by UUIDGEN?"
-  (string-match "\\`[0-9a-f]\\{8\\}-[0-9a-f]\\{4\\}-[0-9a-f]\\{4\\}-[0-9a-f]\\{4\\}-[0-9a-f]\\{12\\}\\'" (downcase s)))
-
 (defun org-in-src-block-p (&optional inside element)
   "Whether point is in a code source block.
 When INSIDE is non-nil, don't consider we are within a source