synchronous log option (emacs shell support)

[neeasade]

Hello,

emacs shell doesn't respect escape codes that manipulate the cursor position to different lines (it tries to be more shell than terminal), and as a result pfetch output looks like: https://0x0.st/zYpX.png (the same output if you pfetch >./test.txt) -- I have the same issue with neofetch. This is a feature request to investigate a simpler output resulting in line-by-line printing.

Thanks, neeasade

edit: A humorous workaround:

tmux new -d -s pfetch "pfetch && echo done && read"
while [ ! "$(echo "$content" | tail -n 1)" = "done" ]; do
    content=$(tmux capture-pane -pS -10 | awk 'NF')
done

echo "$content" | head -n -1
echo

tmux kill-session -t pfetch

[dylanaraps]

This will be fun to solve.

I use the VT100/ANSI escape sequence method as it allows simple storage and printing of both the ASCII and information in a dynamic way. I really can't think of a way to implement the same behavior without the use of cursor movement.

• Is there a list of supported escape sequences?
• Does ansi-term work?

[neeasade]

Is there a list of supported escape sequences?

I can't find a definitive list. I think all the supported sequences are handled by ansi-color-for-comint-mode (shell-mode derives from comint-mode). The regex it uses to look for supported esc codes can be found here [1]. Unsupported esc sequences that are not swallowed as SGR show in the output (eg [2], where I attempt to set window title). I'm actually a little confused as when I run through all the esc codes used in log, they appear to be supported/not print the ^[ on the next line like my example. I wonder if the problem is the [%sA code (move the cursor up, in get_ascii) is just ignored.

Does ansi-term work?

I had assumed it would, but using emacs -Q (vanilla/no config) on emacs 26.1 looks really :S [3]

[1] https://github.com/tomtt/tomtt_emacslisp/blob/63a7698a7e086aa0256e8ef4c5baf6327688cae9/ansi-color.el#L155 [2] https://0x0.st/zYpL.png [3] https://0x0.st/zYpQ.png

edit: confirmed that ansi-color-for-comint-mode does handle the lateral cursor moving escape codes used in log by with M-x ansi-color-mode-for-comint-mode-off

[neeasade]

was looking at very out of date ansi-color above, my bad. This is the current library and looks cleaner as well: https://github.com/emacs-mirror/emacs/blob/d0e2a341dd9a9a365fd311748df024ecb25b70ec/lisp/ansi-color.el#L153

[neeasade]

I've got a patch that matches current behavior here [1] for this (I just make get_ascii special and loop over it, and have a function for padding with spaces) -- my implementation is pretty slow though (~4 times slower than original pfetch on my machine).

[1] https://github.com/neeasade/pfetch/commit/526087e4a5f9f5084d608439a1ebdef104eb5b31

edit: I commited again on that fork reducing subshell usage, now the speed is very comparable (from 0m0.231s to 0m0.285s in the 'real' section of time).

[dylanaraps]

Yeah, I've given up on this. I don't believe it's something I need to fix. If \r isn't supported....