ox: Small refactoring

* lisp/ox.el (org-export-get-loc): Refactor code.  Speed-up processing
  when the element doesn't require line numbering.
* testing/lisp/test-ox.el (test-org-gen-loc-list): Reformat code.

lisp/ox.el

@@ -4450,40 +4450,34 @@ objects of the same type."
 ;; code in a format suitable for plain text or verbatim output.
 
 (defun org-export-get-loc (element info)
-  "Return accumulated lines of code up to ELEMENT.
-
-INFO is the plist used as a communication channel.
-
-ELEMENT is excluded from count."
-  (let ((loc 0)
-        (linum (org-element-property :number-lines element)))
-    (org-element-map (plist-get info :parse-tree)
-	`(src-block example-block ,(org-element-type element))
-      (lambda (el)
-	(cond
-	 ;; ELEMENT is reached: Quit the loop.
-	 ((eq el element))
-	 ;; Only count lines from src-block and example-block elements
-	 ;; with a "+n" or "-n" switch.  A "-n" switch resets counter.
-	 ((not (memq (org-element-type el) '(src-block example-block))) nil)
-	 ((let ((linums (org-element-property :number-lines el)))
-	    (when linums
-	      ;; Accumulate locs or reset them.
-	      (let ((lines (org-count-lines
-			    (org-trim (org-element-property :value el)))))
-		(if (eq (car linums) 'new)
-		    (setq loc 0))
-		(setq loc (+ loc lines (cdr linums))))))
-	  ;; Return nil to stay in the loop.
-	  nil)))
-      info 'first-match)
-    ;; Add the offset from [+-]n to the loc for the final starting
-    ;; number of lines before the first starting line.
-    (setq loc (cl-case (car linum)
-		(continued (+ (cdr linum) loc))
-		(new (cdr linum))))
-    ;; Return value.
-    loc))
+  "Return count of lines of code before ELEMENT.
+
+ELEMENT is an example-block or src-block element.  INFO is the
+plist used as a communication channel.
+
+Count includes every line of code in example-block or src-block
+with a \"+n\" or \"-n\" switch before block.  Return nil if
+ELEMENT doesn't allow line numbering."
+  (pcase (org-element-property :number-lines element)
+    (`(new . ,n) n)
+    (`(continued . ,n)
+     (let ((loc 0))
+       (org-element-map (plist-get info :parse-tree) '(src-block example-block)
+	 (lambda (el)
+	   ;; ELEMENT is reached: Quit loop and return locs.
+	   (if (eq el element) (+ loc n)
+	     ;; Only count lines from src-block and example-block
+	     ;; elements with a "+n" or "-n" switch.
+	     (let ((linum (org-element-property :number-lines el)))
+	       (when linum
+		 (let ((lines (org-count-lines
+			       (org-trim (org-element-property :value el)))))
+		   ;; Accumulate locs or reset them.
+		   (pcase linum
+		     (`(new . ,n) (setq loc (+ n lines)))
+		     (`(continued . ,n) (cl-incf loc (+ n lines)))))))
+	     nil))		      ;Return nil to stay in the loop.
+	 info 'first-match)))))
 
 (defun org-export-unravel-code (element)
   "Clean source code and extract references out of it.

testing/lisp/test-ox.el

@@ -2587,68 +2587,123 @@ Paragraph[fn:1][fn:2][fn:lbl3:C<<target>>][[test]][[target]]
        info t))))
 
 (defun test-org-gen-loc-list(text type)
-    (org-test-with-parsed-data text
-			       (org-element-map tree type
-				 (lambda(el) (or (org-export-get-loc el info) "nil")))))
+  (org-test-with-parsed-data text
+    (org-element-map tree type
+      (lambda (el) (or (org-export-get-loc el info) 'no-loc)))))
 
 (ert-deftest test-org-export/get-loc ()
   "Test `org-export-get-loc' specifications."
   (should
    ;; "-n" resets line number.
    (equal '(0)
-	  (test-org-gen-loc-list  "#+BEGIN_EXAMPLE -n\n  Text\n#+END_EXAMPLE" 'example-block)))
+	  (test-org-gen-loc-list "#+BEGIN_EXAMPLE -n\n  Text\n#+END_EXAMPLE"
+				 'example-block)))
   ;; The first "+n" has 0 lines before it
   (should
    (equal '(0)
-	  (test-org-gen-loc-list "#+BEGIN_EXAMPLE +n\n  Text\n#+END_EXAMPLE" 'example-block)))
+	  (test-org-gen-loc-list "#+BEGIN_EXAMPLE +n\n  Text\n#+END_EXAMPLE"
+				 'example-block)))
   ;; "-n 10" resets line number but has "9 lines" before it.
   (should
    (equal '(9)
-	  (test-org-gen-loc-list "#+BEGIN_EXAMPLE -n 10\n  Text\n#+END_EXAMPLE" 'example-block)))
+	  (test-org-gen-loc-list "#+BEGIN_EXAMPLE -n 10\n  Text\n#+END_EXAMPLE"
+				 'example-block)))
   ;; -n10 with two lines then +n 15
   (should
    (equal '(9 25)
-	  (test-org-gen-loc-list "#+BEGIN_EXAMPLE -n 10\n  Text_10\n  Second line(11)\n#+END_EXAMPLE
-#+BEGIN_EXAMPLE +n 15\n  Text line (11 + 15)\n#+END_EXAMPLE"  'example-block)))
+	  (test-org-gen-loc-list "
+#+BEGIN_EXAMPLE -n 10
+  Text_10
+  Second line(11)
+#+END_EXAMPLE
+#+BEGIN_EXAMPLE +n 15
+  Text line (11 + 15)
+#+END_EXAMPLE"
+				 'example-block)))
   (should
    (equal '(9 19 0)
-	  (test-org-gen-loc-list "#+BEGIN_EXAMPLE -n 10\n  Text\n#+END_EXAMPLE
-#+BEGIN_EXAMPLE +n 10\n  Text \n#+END_EXAMPLE\n
-#+BEGIN_EXAMPLE -n\n  Text \n#+END_EXAMPLE" 'example-block)))
+	  (test-org-gen-loc-list "
+#+BEGIN_EXAMPLE -n 10
+  Text
+#+END_EXAMPLE
+#+BEGIN_EXAMPLE +n 10
+  Text
+#+END_EXAMPLE
+
+#+BEGIN_EXAMPLE -n
+  Text
+#+END_EXAMPLE"
+				 'example-block)))
+  ;; an Example Block without -n does not add to the line count.
   (should
-   ;; an Example Block without -n does not add to the line count
-   (equal '(9 "nil" 19)
-	  (test-org-gen-loc-list "#+BEGIN_EXAMPLE -n 10\n  Text\n#+END_EXAMPLE
-#+BEGIN_EXAMPLE\n  Text\n#+END_EXAMPLE
-#+BEGIN_EXAMPLE +n 10\n  Text\n#+END_EXAMPLE" 'example-block)))
+   (equal '(9 no-loc 19)
+	  (test-org-gen-loc-list "
+#+BEGIN_EXAMPLE -n 10
+  Text
+#+END_EXAMPLE
+#+BEGIN_EXAMPLE
+  Text
+#+END_EXAMPLE
+#+BEGIN_EXAMPLE +n 10
+  Text
+#+END_EXAMPLE"
+				 'example-block)))
+  ;; "-n" resets line number.
   (should
-   ;; "-n" resets line number.
-   (equal '(0)
-	  (test-org-gen-loc-list "#+BEGIN_SRC emacs-lisp -n \n  (- 1 1) \n#+END_SRC" 'src-block)))
+   (equal
+    '(0)
+    (test-org-gen-loc-list "#+BEGIN_SRC emacs-lisp -n \n  (- 1 1) \n#+END_SRC"
+			   'src-block)))
+  ;; The first "+n" has 0 lines before it.
   (should
-   ;; The first "+n" has 0 lines before it
    (equal '(0)
-	  (test-org-gen-loc-list "#+BEGIN_SRC emacs-lisp +n \n  (+ 0 (- 1 1))\n#+END_SRC" 'src-block)))
+	  (test-org-gen-loc-list
+	   "#+BEGIN_SRC emacs-lisp +n \n  (+ 0 (- 1 1))\n#+END_SRC"
+	   'src-block)))
+  ;; "-n 10" resets line number but has "9 lines" before it.
   (should
-   ;; "-n 10" resets line number but has "9 lines" before it.
    (equal '(9)
-	  (test-org-gen-loc-list "#+BEGIN_SRC emacs-lisp -n 10\n  (- 10 1)\n#+END_SRC" 'src-block)))
+	  (test-org-gen-loc-list
+	   "#+BEGIN_SRC emacs-lisp -n 10\n  (- 10 1)\n#+END_SRC"
+	   'src-block)))
   (should
    (equal '(9 25)
-	  (test-org-gen-loc-list "#+BEGIN_SRC emacs-lisp -n 10\n  (- 10 1)\n  (+ (- 10 1) 1)\n#+END_SRC
-#+BEGIN_SRC emacs-lisp +n 15\n  (+ (- 10 1) 2 (- 15 1))\n#+END_SRC" 'src-block)))
+	  (test-org-gen-loc-list "
+#+BEGIN_SRC emacs-lisp -n 10
+  (- 10 1)
+  (+ (- 10 1) 1)
+#+END_SRC
+#+BEGIN_SRC emacs-lisp +n 15
+  (+ (- 10 1) 2 (- 15 1))
+#+END_SRC"
+				 'src-block)))
   (should
    (equal '(9 19 0)
-	  (test-org-gen-loc-list "#+BEGIN_SRC emacs-lisp -n 10\n  (- 10 1)\n#+END_SRC
-#+BEGIN_SRC emacs-lisp +n 10\n  (+ (- 10 1) 1 (- 10 1))\n#+END_SRC
-#+BEGIN_SRC emacs-lisp -n\n  (- 1 1)\n#+END_SRC" 'src-block)))
+	  (test-org-gen-loc-list "
+#+BEGIN_SRC emacs-lisp -n 10
+  (- 10 1)
+#+END_SRC
+#+BEGIN_SRC emacs-lisp +n 10
+  (+ (- 10 1) 1 (- 10 1))
+#+END_SRC
+#+BEGIN_SRC emacs-lisp -n
+  (- 1 1)
+#+END_SRC"
+				 'src-block)))
+  ;; A SRC Block without -n does not add to the line count.
   (should
-   ;; an SRC Block without -n does not add to the line count
-   (equal '(9 "nil" 19)
+   (equal '(9 no-loc 19)
 	  (test-org-gen-loc-list
-	   "#+BEGIN_SRC emacs-lisp -n 10\n  (+ (-10 1) 1)\n#+END_SRC
-#+BEGIN_SRC emacs-lisp \n  (+ 2 2) \n#+END_SRC
-#+BEGIN_SRC emacs-lisp +n 10\n  (+ (- 10 1) 1 (- 10 1))\n#+END_SRC" 'src-block))))
+	   "#+BEGIN_SRC emacs-lisp -n 10
+  (+ (-10 1) 1)
+#+END_SRC
+#+BEGIN_SRC emacs-lisp
+  (+ 2 2)
+#+END_SRC
+#+BEGIN_SRC emacs-lisp +n 10
+  (+ (- 10 1) 1 (- 10 1))
+#+END_SRC"
+	   'src-block))))
 
 (ert-deftest test-org-export/resolve-coderef ()
   "Test `org-export-resolve-coderef' specifications."