bug#23675: Feature request: Emacs 25.0.94: count-lines should offer a way to ignore invisible lines, e.g. outline mode

[Stefan Monnier]

>> ! (defun count-lines (start end)
>>     "Return number of lines between START and END.
>>   This is usually the number of newlines between them,
>>   but can be one more if START is not equal to END
>> ! and the greater of them is not at the start of a line."
>>     (save-excursion
>>       (save-restriction
>>         (narrow-to-region start end)
>>         (goto-char (point-min))
>> !       (if (eq selective-display t)
>> !      (save-match-data
>
> Hm...  the current version of the function doesn't mention
> selective-display at all,

That's because the t value of selective-display has been described as
obsolete in the manual since 2013.


        Stefan