Re: for a given emacs session: insert a subject with an increasing counter

[Eric Abrahamsen <eric@ericabrahamsen.net>]

Uwe Brauer <oub@mat.ucm.es> writes:

>>>> "EB" == Emanuel Berg <moasenwood@zoho.eu> writes:
>
>> Uwe Brauer wrote:
>
> Thanks for your advice:
>
> I have now
>
> (defun my-reset-subject-counter () 
>   "Reset the counter to ZERO!"
>   (interactive)
>   (setq my-subject-counter 0)
>   (message "Counter value is NOW: %s" my-subject-counter))
>
> (defun my-new-insert-subject-counter (total)
>   "Insert a string of the form [`counter/Total'] "
>   (interactive "nTotal number: ")
>   (save-excursion
>     (setq my-subject-counter (+ my-subject-counter 1))
>     (message-carefully-insert-headers (list (cons 'Subject (format "[%s/%s]" my-subject-counter total))))))
>
> But this part I don't understand
>
>
>> (require 'cl-lib)
>
>> (defun ...
>>   (cl-incf my-subject-counter) ... )

The line above "increments" an integer variable "in place", in other
words that line is the exact equivalent of:

(setq my-subject-counter (+ my-subject-counter 1))

In effect, the `cl-incf' "contains" the `setq' inside it.