expectperl-discuss

[Expectperl-discuss] several sequental spawns

[Alexey M. <mo...@no...>]

It looks like perl-Expect doesn't support for several subsequent spawns
for on objects, smth like this

my $expect = Expect->new(...);
# setting some parameters for the object created
#...
$expect->spawn('first_program',@parameters);
$expect->expect(smth);
$expect->soft_close or $expect->hard_close;
print $expect->existatus;
...

$expect->spawn('another_program',@parameters);

I got a message here in logs telling that /dev/pts/7 which was used for
the first program interaction doesn't exist anymore (no such file or
directory)

If I replace the second $expect->spawn with Expect->spawn the program
works Ok. Is there a way to skip creation of another Expect object, or
at least cloning settings from the first object to the second one?

Alexey Morozov

Re: [Expectperl-discuss] several sequental spawns

[Austin S. <te...@of...>]

> I got a message here in logs telling that /dev/pts/7 which was used for
> the first program interaction doesn't exist anymore (no such file or
> directory)
> 
> If I replace the second $expect->spawn with Expect->spawn the program
> works Ok. Is there a way to skip creation of another Expect object, or
> at least cloning settings from the first object to the second one?
> 

	You would be able to do something like:

$new_expect = Expect->new();
%{ *$new_expect } = %{ *$old_expect };

	except there are are a few variables you don't want to change, such
as the name of the pty, etc.
	If there are a few settings in particular you are interested in
setting it would probably be easiest to copy them before you destroy
to old object, e.g.:


sub copy_settings {
  my($old,$new) = @_;
  $new->exp_internal($old->exp_internal());
  ...
}

$new = Expect->new();
copy_settings($old,$new);
undef($old);

	As Roland says, we might want to make this a new sub in the Expect
module. I'm not sure which items we'd want to have in there by default,
e.g. terminal params(?).

	Austin

Re: [Expectperl-discuss] several sequental spawns

[Alexey M. <mo...@no...>]

=F7 =F0=CE=C4, 18.03.2002, =D7 21:18, Austin Schutz =CE=C1=D0=C9=D3=C1=CC:
> 	You would be able to do something like:
> $new_expect =3D Expect->new();
> %{ *$new_expect } =3D %{ *$old_expect };
Looks like an ugly hack probably leading to memory leaks and
unpredictable behaviour :-). My C++'ish past protests against things
like this :-)

> 	If there are a few settings in particular you are interested in
> setting it would probably be easiest to copy them before you destroy
> to old object, e.g.:
> sub copy_settings {
>   my($old,$new) =3D @_;
>   $new->exp_internal($old->exp_internal());
>   ...
> }
sounds reasonable. May be it's time to add a 'clone' function to Expect?
All 'shareable' settings are to be copied inside the func, and unique
ones get re-created... Unfortunately I know too little about an Expect's
object insides for the moment and probably can't say exactly whether
'clone' should allocate a new pty for each new instance etc...

> 	As Roland says, we might want to make this a new sub in the Expect
> module. I'm not sure which items we'd want to have in there by default,
> e.g. terminal params(?).
Hmm, looks like I just repeated your words before reading entire message
:-)...

Thank you and Roland a lot (but I can't see his mail in my box yet :-(
).

Alexey Morozov

Re: [Expectperl-discuss] several sequental spawns

[Austin S. <te...@of...>]

> > 	If there are a few settings in particular you are interested in
> > setting it would probably be easiest to copy them before you destroy
> > to old object, e.g.:
> > sub copy_settings {
> >   my($old,$new) = @_;
> >   $new->exp_internal($old->exp_internal());
> >   ...
> > }
> sounds reasonable. May be it's time to add a 'clone' function to Expect?
> All 'shareable' settings are to be copied inside the func, and unique
> ones get re-created... Unfortunately I know too little about an Expect's
> object insides for the moment and probably can't say exactly whether
> 'clone' should allocate a new pty for each new instance etc...
> 

	I think you would have to. So, the purpose of the clone would be
to do something like spawn a process using the same parameters? I guess I'm
not seeing much benefit over setting the default parameters using package
variables, e.g. $Expect::Exp_Internal. Maybe I don't understand the concept
of 'clone' well enough.
	Also, how would it apply to filehandles expectified using 
exp_init?

> > 	As Roland says, we might want to make this a new sub in the Expect
> > module. I'm not sure which items we'd want to have in there by default,
> > e.g. terminal params(?).
> Hmm, looks like I just repeated your words before reading entire message
> :-)...
> 
	Maybe, but you use new and interesting vocabulary. :-)

> Thank you and Roland a lot (but I can't see his mail in my box yet :-(
> ).

	Mostly Roland. He's been doing all the work lately :)

	Austin