Re: ielm automatic saving of history -- bug 67000

[Madhu]

*  Eli Zaretskii <eliz@gnu.org> <865xpsr3b0.fsf@gnu.org>
Wrote on Wed, 16 Oct 2024 09:04:51 +0300
>> Apparently using utf-8-unix
>> is sufficient to encode the contents of the buffer beings saved
>> without any loss of data.
>
> It is not.  It can only safely encode characters that are inside the
> Unicode codepoint space, and raw bytes are outside that range.
>
>> The file written is identical to the file which was read.
>
> I don't understand what you mean.  AFAIU, IELM history records what
> you typed, so what file was read here?

the ielm-history file from which the comint-input-ring is initalized

If I copy my ~/.ielm-history.el to /dev/shm/2.txt.binary and run


```
(let ((comint-input-ring-file-name "/dev/shm/2.txt.binary")) 
(comint-read-input-ring))
```

it initializes the input-ring from the history. emacs apparently reads this in 
raw-text-unix.


```
(let ((comint-input-ring-file-name "/dev/shm/2.txt.out")) 
(comint-write-output-ring))
```

Here I am prompted with the coding system warning . If i go ahead and qchoose
utf-8-unix, it goes ahead and saves it. I can compare 2.txt.binary and
2.txt.out to see that utf-8-unix has not resulted in any data loss.
Hence all the claims in my previous message.