Re: eshell pipelines

[Thierry Volpiatto]

David Hansen <david.hansen@gmx.net> writes:

> [For emacs-devel: 
>
> In gnu.emacs.help there is a discussion about some little eshell,
> eshell/ls bug.  Processes in a pipeline get a TTY for IO (via
> `start-process').  Quite some programs behave different whether they
> have a TTY or not. 
>
> The other thing is that eshell/ls does not output one file per line
> when in a pipeline (as the usual GNU ls does).]
>
> On Wed, 13 Aug 2008 13:21:00 +0200 Thierry Volpiatto wrote:
>
>> As Lennart said you call ls with -1 arg or you can always call ls with
>> this arg setting it like that:
>>
>> ,----
>> | (setq eshell-ls-initial-args '(-1)) 
>> `----
>>
>> now when you call for example "ls | wc -l" , you will have the
>> good number of lines.
>>
>> It would be cool to have a function to call in some hook to call ls -1
>> only if there is a "|" after ls, this function do that but i need a hook
>> to call it:
>>
>> ,----
>> | (defun eshell-set-ls ()
>> |   (let ((com-line
>> |          (eshell-parse-arguments (re-search-backward "ls") 
>> (line-end-position))))
>> |     (if (equal (nth 1 com-line) '(eshell-operator "|"))
>> |         (setq eshell-ls-initial-args '(-1))
>> |         (setq eshell-ls-initial-args nil))))
>> `----
>
> Try the attached patch.  It
>
>  * Starts subprocesses in a (eshell) pipeline using a pipe and not a TTY
>    (this should also give some performance boost).
>
>  * Appends "-1" to eshell/ls if ls is called in a pipeline.
>
> At the time it's feature freeze for Emacs so it will probably take some
> time to make it in there.  Cc: anyways, maybe some old timer can approve
> the two lines.

After some quick tests that work fine.
Thank you.

>
> *** em-ls.el.~1.33.~  2008-06-07 20:14:50.000000000 +0200
> --- em-ls.el  2008-08-13 14:05:43.000000000 +0200
> ***************
> *** 299,304 ****
> --- 299,306 ----
>     (let ((insert-func 'eshell-buffered-print)
>       (error-func 'eshell-error)
>       (flush-func 'eshell-flush))
> +     ;; In pipelines use the -1 switch.
> +     (and eshell-in-pipeline-p (push "-1" args))
>       (eshell-do-ls args)))
>   
>   (put 'eshell/ls 'eshell-no-numeric-conversions t)
> *** esh-proc.el.~1.21.~       2008-05-12 20:30:41.000000000 +0200
> --- esh-proc.el       2008-08-13 14:20:38.000000000 +0200
> ***************
> *** 249,260 ****
>        proc decoding encoding changed)
>       (cond
>        ((fboundp 'start-process)
> !       (setq proc
> !         (apply 'start-process
> !                (file-name-nondirectory command) nil
> !                ;; `start-process' can't deal with relative
> !                ;; filenames
> !                (append (list (expand-file-name command)) args)))
>         (eshell-record-process-object proc)
>         (set-process-buffer proc (current-buffer))
>         (if (eshell-interactive-output-p)
> --- 249,262 ----
>        proc decoding encoding changed)
>       (cond
>        ((fboundp 'start-process)
> !       ;; Don't use a TTY for processes in a pipeline.
> !       (let ((process-connection-type (not eshell-in-pipeline-p)))
> !         (setq proc
> !               (apply 'start-process
> !                      (file-name-nondirectory command) nil
> !                      ;; `start-process' can't deal with relative
> !                      ;; filenames
> !                      (append (list (expand-file-name command)) args))))
>         (eshell-record-process-object proc)
>         (set-process-buffer proc (current-buffer))
>         (if (eshell-interactive-output-p)

-- 
A + Thierry Volpiatto
Location: Saint-Cyr-Sur-Mer - France