RE: [External] : Re: Operating the HIST feature of completing-read

[carlmarcos]

Jul 12, 2022, 14:28 by drew.adams@oracle.com:

>> Here is practically how history works:
>>
>> 1) First you define history variable:
>> (defvar my-history nil "...previous inputs.") ⇒ my-history
>>
>> 2) You use the history variable:
>> (completing-read "X: " '("a" "b") nil nil nil 'my-history) ⇒ "a"
>>
Does the history remember the the user input associated with each specific 
completing-read call?


>> 3) Now you may inspect history variable:
>> my-history ⇒ ("a")
>>
>> 4) Now you may inspect the file (find-file "~/.emacs.d/history")
>>  where history variable will be recorded so that
>>  history works over Emacs sessions
>>
>> 5) You may browse through history by using M-n and M-p as to easy
>>  selection of your previously recorded choices (history).
>>
>
> Good summary.  Some more:
>
> 1. If you don't pass a value as the HIST arg to
> minibuffer-reading functions such as `completing-read'
> then the implied, general history variable is used:
> `minibuffer-history'.
>
> IOW, your minibuffer-input history is always
> recorded in a history variable, whether or not you
> pass a HIST variable.
>
> If you want to keep a separate history list for some
> interactions then pass a separate history variable.
> If you don't care about keeping a separate list for
> some inputs then don't pass an explicit HIST.
>
> 2. How do you make use of the history list currently
> available during a read from the minibuffer?  As
> Jean mentioned, use `M-p' and `M-n' to cycle among
> historical inputs.  Or use `M-r' and `M-s' to access
> them directly by matching regexps.
>
> 3. Ask Emacs!
>
> `C-h r', `i histor TAB', choose a candidate such as
> `history of minibuffer input'.  That takes you to
> node `Minibuffer History' in the Emacs manual:
>
> https://www.gnu.org/software/emacs/manual/html_node/emacs/Minibuffer-History.html
>
> `C-h i m el', `i histor TAB', choose a candidate
> such as `history list'.  That takes you to node
> `Minibuffer History' in the Elisp manual:
>
> https://www.gnu.org/software/emacs/manual/html_node/elisp/Minibuffer-History.html
>
> Emacs answers your questions.  And by asking Emacs
> you learn to converse with Emacs, i.e., to ask it
> better, posing your questions using terms that
> Emacs understands best.  (And those terms are also
> those best understood by the Emacs community, if
> you do ask outside Emacs itself.)
>
> Do yourself a favor and learn to communicate with
> Emacs more fluently.  There are many levels/layers
> to explore & learn, and each opens doors to others.
>
> Learning how to talk with Emacs is more productive
> than posing lots of one-off questions here and
> there.  And if you do pose questions about Emacs
> outside Emacs then the most helpful questions will
> be about ways how to converse with Emacs (asking
> about asking Emacs).
>