bug#6085: Eshell doesn't handle ANSI escapes/colors well

bug#6085: Eshell doesn't handle ANSI escapes/colors well

[Ken Hori]

From Emacs bzr HEAD:

Eshell doesn't handle a terminal escape code like ^[.

My eshell-output-filter-functions:
 '(eshell-output-filter-functions (quote (eshell-handle-ansi-color
eshell-handle-control-codes eshell-watch-for-password-prompt
eshell-postoutput-scroll-to-bottom)))

Example:
[~/emacs.20100501/lisp/eshell]$ export TERM=xterm-256color
[~/emacs.20100501/lisp/eshell]$ *grep --color=auto ansi esh-*
^[[Kesh-mode.el^[[K^[[K:^[[K    eshell-handle-^[[Kansi^[[K-color
^[[Kesh-mode.el^[[K^[[K:^[[K(autoload
'^[[Kansi^[[K-color-apply-on-region "^[[Kansi^[[K-color")
^[[Kesh-mode.el^[[K^[[K:^[[K(defun eshell-handle-^[[Kansi^[[K-color ()
^[[Kesh-mode.el^[[K^[[K:^[[K  (^[[Kansi^[[K-color-apply-on-region
eshell-last-output-start
^[[Kesh-mode.el^[[K^[[K:^[[K		   'eshell-handle-^[[Kansi^[[K-color)
^[[Kesh-var.el^[[K^[[K:^[[K;; is identical to just saying (lisp); but
with the variable exp^[[Kansi^[[Kon


`term-handle-ansi-escape' from term.el seems to be be handling
ansi escapes very well. Maybe we can integrate  a modified
version of it into Eshell.

bug#6085: Eshell doesn't handle ANSI escapes/colors well

[Thierry Volpiatto]

Ken Hori <fplemma@gmail.com> writes:

> From Emacs bzr HEAD:
>
> Eshell doesn't handle a terminal escape code like ^[.
>
> My eshell-output-filter-functions:
>  '(eshell-output-filter-functions (quote (eshell-handle-ansi-color
> eshell-handle-control-codes eshell-watch-for-password-prompt
> eshell-postoutput-scroll-to-bottom)))
>
> Example:
> [~/emacs.20100501/lisp/eshell]$ export TERM=xterm-256color
> [~/emacs.20100501/lisp/eshell]$ *grep --color=auto ansi esh-*
> ^[[Kesh-mode.el^[[K^[[K:^[[K    eshell-handle-^[[Kansi^[[K-color
> ^[[Kesh-mode.el^[[K^[[K:^[[K(autoload
> '^[[Kansi^[[K-color-apply-on-region "^[[Kansi^[[K-color")
> ^[[Kesh-mode.el^[[K^[[K:^[[K(defun eshell-handle-^[[Kansi^[[K-color ()
> ^[[Kesh-mode.el^[[K^[[K:^[[K  (^[[Kansi^[[K-color-apply-on-region
> eshell-last-output-start
> ^[[Kesh-mode.el^[[K^[[K:^[[K		   'eshell-handle-^[[Kansi^[[K-color)
> ^[[Kesh-var.el^[[K^[[K:^[[K;; is identical to just saying (lisp); but
> with the variable exp^[[Kansi^[[Kon
>
>
> `term-handle-ansi-escape' from term.el seems to be be handling
> ansi escapes very well. Maybe we can integrate  a modified
> version of it into Eshell.

This was working some time ago so maybe looking at what have changed and
reenable this feature should be good.

-- 
Thierry Volpiatto
Gpg key: http://pgp.mit.edu/

bug#6085: Eshell doesn't handle ANSI escapes/colors well

[Chong Yidong]

>> Eshell doesn't handle a terminal escape code like ^[.
>>
>> [~/emacs.20100501/lisp/eshell]$ export TERM=xterm-256color
>> [~/emacs.20100501/lisp/eshell]$ *grep --color=auto ansi esh-*
>> ^[[Kesh-mode.el^[[K^[[K:^[[K    eshell-handle-^[[Kansi^[[K-color
>
> This was working some time ago so maybe looking at what have changed and
> reenable this feature should be good.

No, this is not a regression.  The mess here is due to the ^[[K ("erase
line") sequence that colorized grep emits.  (I don't know why it needs
this control sequence.)

There is no sane way for the ansi-color package to handle this.  Unlike
term.el, it is not intended to be a terminal emulator.  The best we can
do is to delete such sequences from the output, and I've committed a
change to do that.