Re: Help - Tcl/Expect Parsing Strangeness In Emacs Shell

[Don Libes <libes@nist.gov>]

Emacs plays around with tty settings in a way that can break
simplistic Expect scripts.  Have you read the Expect man page - it
talks about this and how to avoid it.  The Expect book has a section
that describes the same thing albeit in a different way.

Don

"Tennis Smith" <tennis_smith@yahoo-remove-to-reply.com> writes:

> Hi,
> 
> Apologies for the wide distribution. This is in one of those grey areas
> between tools so I'm not sure where it fits. I tried posting this once
> before
> with a "tar" file containing my test scripts, but  the mailer barfed back at
> me.
> 
> The problem is that in certain circumstances, Tcl/Expect doesn't work
> correctly
> while in an Emacs shell.  Application output that Expect is "expecting"
> will not be detected.
> 
> I ran into this while trying to parse the output of a telnet session to an
> MS
> Windows machine.  Initially, I thought it was something wrong with the
> Windows output (or with your humble programmer ;-)). But after much
> debugging, I've narrowed it down to two salient facts:
> 
> 1 - Everything works correctly on rxvt, xterm and Emacs version
> 20.7.1 and earlier.
> 
> 2 - The only environment that consistently has this occur is Emacs versions
> 21.2.95.2 and later.
> 
> Steps To Recreate:
> 
> Below are two tiny scripts.
> 
>  The "test.exp" script spawns a task. The "datagen.tcl" script is
> called in the spawned task and simply writes to the screen. The "test.exp"
> then reads output from "datagen.tcl" Run the "test.exp" script with the
> "datagen.tcl" script in the same directory.
> 
> When everything is working _correctly_, you'll see two copies of  command
> output from "datagen.tcl", one from stdout and one printed from  expect
> itself.
> 
> If run under an xterm, expect will be able to detect output and put it into
> the "accum" variable (which is then printed). But, if run in a shell under
> Emacs, expect will not detect the data and will put only blank lines into
> the "accum" variable.
> 
> Has anyone else seen this or know how to fix it?
> 
> TIA,
> -Tennis
> 
> #!/bin/sh
> #
> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> x
> set starter { ${1:+"$@"}
>     shift
>     shift
>     exec expect -f $0 -- ${1:+"$@"}
> }
> #
> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> x
> #
> # Ive tried this test under tcsh and bash. Both have the same
> # result.
> #
> puts ">>>>>>>>BEGIN VERSION INFO<<<<<<<<<<\
>      \nTCL VERSION:\ntcl version [info tclversion]\n\
>      \nEXPECT VERSION:\n[exec expect -v]\n\
>      \nBASH Version:\n[exec bash --version]\n\
>      \nTCSH Version:\n [exec tcsh --version]\n\
>      \n>>>>>>>END VERSION INFO<<<<<<<<<<<<<<\n\n"
> spawn bash
> exp_send "./datagen.tcl\n"
> set accum {}
> expect {
>     -re " " {
>         set accum "${accum}$expect_out(buffer)"
>         exp_continue
>     }
>     timeout {
>         if {![string length $expect_out(buffer)]} {
>             set accum  "timed out waiting for data"
>         } else {
>             set accum "${accum}\n\nFinal timeout\n"
>         }
>     }
> }
> puts "accum:$accum"
> 
> # End of test.exp
> 
> 
> #!/bin/sh
> #
> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> x
> set starter { ${1:+"$@"}
>     shift
>     shift
>     exec expect -f $0 -- ${1:+"$@"}
> }
> #
> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> x
> puts "ipconfig\
> \n\nWindows 2000 IP Configuration\
> \n\nEthernet adapter 126 Network:\
> \n\n    Connection-specific DNS Suffix  . : \
> \n      IP Address. . . . . . . . . . . . : 0.0.0.0\
> \n      Subnet Mask . . . . . . . . . . . : 0.0.0.0\
> \n      Default Gateway . . . . . . . . . : \
> \n\nEthernet adapter 172 Network:\
> \n\n    Connection-specific DNS Suffix  . : \
> \n      IP Address. . . . . . . . . . . . : 172.19.178.242\
> \n      Subnet Mask . . . . . . . . . . . : 255.255.255.0\
> \n      Default Gateway . . . . . . . . . : 172.19.178.1"
> # End of datagen.tcl
> 
> --
> Remove "-remove-to-reply" to respond to my  email address directly.