Using readline with Emacs shell or eshell or ???

Using readline with Emacs shell or eshell or ???

[Robert L. Knighten]

I am writing a command line program in which I want to have command line
editing, command and argument completion, history, etc.  The GNU Readline
package does this quite nicely, BUT my users will often actually want to
invoke the program inside the Emacs shell or perhaps eshell.  Of course
command line editing works just fine, but command and argument completion are
lost.  What is the best way of working around this?

I'm prepared to write some substantial elisp if that is the way to go.  But I
hope there is something already done.

-- Bob

-- 
Robert L. Knighten
Robert@Knighten.org

Re: Using readline with Emacs shell or eshell or ???

[John W. Eaton]

Robert@Knighten.org (Robert L. Knighten) writes:

> I am writing a command line program in which I want to have command line
> editing, command and argument completion, history, etc.  The GNU Readline
> package does this quite nicely, BUT my users will often actually want to
> invoke the program inside the Emacs shell or perhaps eshell.  Of course
> command line editing works just fine, but command and argument completion are
> lost.  What is the best way of working around this?
> 
> I'm prepared to write some substantial elisp if that is the way to go.  But I
> hope there is something already done.

For an example that works (but might not be the best implementation)
take a look at the inferior-octave-complete function in the Emacs mode
for running Octave inside Emacs (octave-inf.el).  The Emacs function
for completion sends a command to Octave to generate completions and
then displays them.  It uses comint for some of the ugly stuff, so the
amount of Lisp code specific to the Octave mode is relatively small.
If you can make it smaller and cleaner, I'd be interested in patches.

jwe

-- 
www.octave.org        | Unfortunately we were hopelessly optimistic in 1954
www.che.wisc.edu/~jwe | about the problems of debugging FORTRAN programs.
                      |                                       -- J. Backus

Re: Using readline with Emacs shell or eshell or ???

[Stefan Monnier]

> For an example that works (but might not be the best implementation)
> take a look at the inferior-octave-complete function in the Emacs mode
> for running Octave inside Emacs (octave-inf.el).  The Emacs function
> for completion sends a command to Octave to generate completions and
> then displays them.  It uses comint for some of the ugly stuff, so the

I haven't looked at how octave-inf.el does it, but gud.el does it
as well when interacting with gdb, so you can also look at that
one.  If you look at both and get some insight, I'd like to
hear about it.


        Stefan

Re: Using readline with Emacs shell or eshell or ???

[Ilya Zakharevich]

[A complimentary Cc of this posting was sent to
Stefan Monnier
<monnier+gnu.emacs.help/news/@flint.cs.yale.edu>], who wrote in article <5lhe8fion1.fsf@rum.cs.yale.edu>:
> > For an example that works (but might not be the best implementation)
> > take a look at the inferior-octave-complete function in the Emacs mode
> > for running Octave inside Emacs (octave-inf.el).  The Emacs function
> > for completion sends a command to Octave to generate completions and
> > then displays them.  It uses comint for some of the ugly stuff, so the
> 
> I haven't looked at how octave-inf.el does it, but gud.el does it
> as well when interacting with gdb, so you can also look at that
> one.  If you look at both and get some insight, I'd like to
> hear about it.

IIRC, gdb has "complete" command.  GUD erases the current line, sends
the complete command, processes the output, then restores the current
line and acts on the completion list.

Do not think one can do anything with a random non-cooperating program.

Hope this helps,
Ilya

Re: Using readline with Emacs shell or eshell or ???

[Robert L. Knighten]

Ilya Zakharevich <nospam-abuse@ilyaz.org> writes:

> [A complimentary Cc of this posting was sent to
> Stefan Monnier
> <monnier+gnu.emacs.help/news/@flint.cs.yale.edu>], who wrote in article <5lhe8fion1.fsf@rum.cs.yale.edu>:
> > > For an example that works (but might not be the best implementation)
> > > take a look at the inferior-octave-complete function in the Emacs mode
> > > for running Octave inside Emacs (octave-inf.el).  The Emacs function
> > > for completion sends a command to Octave to generate completions and
> > > then displays them.  It uses comint for some of the ugly stuff, so the
> > 
> > I haven't looked at how octave-inf.el does it, but gud.el does it
> > as well when interacting with gdb, so you can also look at that
> > one.  If you look at both and get some insight, I'd like to
> > hear about it.
> 
> IIRC, gdb has "complete" command.  GUD erases the current line, sends
> the complete command, processes the output, then restores the current
> line and acts on the completion list.
> 
> Do not think one can do anything with a random non-cooperating program.
> 
> Hope this helps,
> Ilya
> 
gud was the first thing I looked at, but as noted it is based on a really
tight interaction with the debugger and is very complex as a result.

I'v now played with octave-inf.el and even it is overkill for the rather
simple program that I am building.  But it is very clean and it appears that
it will serve as an excellent base for what I do need.

Thank you for the comments.

-- Bob

-- 
Robert L. Knighten
Robert@Knighten.org