org-clock.el: clocktable ':formula %' now includes per-file time pct

* lisp/org-clock.el (org-clocktable-write-default): When ':formula %'
  is in-effect, show the per-file time percentage in the '%' column.

TINYCHANGE

This change only has an effect when multiple files are contributing to
a given clocktable (such as when ':scope agenda' has been specified).
The existing behavior is that such tables have an extra 'File' column,
and each individual file that contributes has its own summary line
with the headline value '*File time*'.  Those summary rows also
produce a rollup time value for the file in the 'Time' column.

Prior to this change, the built-in '%' formula does not produce a
calculation for those per-file times in the '%' column (the relevant
cells in the '%' column were blank).  With this change, the percentage
contribution of each individual file time to the total time is shown.

The more agenda files you have, the more useful this behavior becomes.

Signed-off-by: Alan D. Salewski <ads@salewski.email>

lisp/org-clock.el

@@ -2702,7 +2702,18 @@ from the dynamic block definition."
 	     (format (concat "| %s %s | %s%s%s"
 			     (format org-clock-file-time-cell-format
 				     (org-clock--translate "File time" lang))
-			     " | *%s*|\n")
+
+			     ;; The file-time rollup value goes in the first time
+			     ;; column (of which there is always at least one)...
+			     " | *%s*|"
+			     ;; ...and the remaining file time cols (if any) are blank.
+			     (make-string (max 0 (1- time-columns)) ?|)
+
+			     ;; Optionally show the percentage contribution of "this"
+			     ;; file time to the total time.
+			     (if (eq formula '%) " %s |" "")
+			     "\n")
+
 		     (file-name-nondirectory file-name)
 		     (if level?    "| " "") ;level column, maybe
 		     (if timestamp "| " "") ;timestamp column, maybe
@@ -2710,7 +2721,12 @@ from the dynamic block definition."
 		     (if properties	    ;properties columns, maybe
 			 (make-string (length properties) ?|)
 		       "")
-		     (org-duration-from-minutes file-time)))) ;time
+		     (org-duration-from-minutes file-time) ;time
+
+		     (cond ((not (eq formula '%)) "")	   ;time percentage, maybe
+			   ((or (not total-time) (= total-time 0)) "0.0")
+			   (t
+			    (format "%.1f" (* 100 (/ file-time (float total-time)))))))))
 
 	  ;; Get the list of node entries and iterate over it
 	  (when (> maxlevel 0)