I have an example Perl script that uses Term::ReadLine::Gnu to provide
ReadLine support with command history:

#!/usr/local/bin/perl
use Term::ReadLine;
use Term::ReadLine::Gnu;

my $term = new Term::ReadLine "test";

while () {
$_ = $term->readline ("Command:");

last if !$_;

print "Read command: $_\n":
} # while

exit;

When run it runs fine, doesn't do much, but dutifully reads commands
and stores them in the history. IOW up arrow works to recall commands
and I can edit them. IOW Term::ReadLine::Gnu is installed properly and
functioning.

Now I wish to debug this script. So I do perl -d testReadLine.pl.
Initially the Perl debugger works. I can do commands like l for list
or s for step. However, as soon as I return from the new
Term::ReadLine the debugger is confused. No command does anything.

I fully suspect that the problem lies in the fact that both my Perl
script and the Perl debugger are fighting over STDIN/STDOUT and
confusing each other. The question is how to get them both to play
nice.

Suggestions? Workarounds? Solutions?

Quoth Andrew DeFaria <adefaria [at] gmail.com>:
> I have an example Perl script that uses Term::ReadLine::Gnu to provide
> ReadLine support with command history:
>
> #!/usr/local/bin/perl
> use Term::ReadLine;
> use Term::ReadLine::Gnu;
>
<snip>
>
> When run it runs fine, doesn't do much, but dutifully reads commands
> and stores them in the history. IOW up arrow works to recall commands
> and I can edit them. IOW Term::ReadLine::Gnu is installed properly and
> functioning.
>
> Now I wish to debug this script. So I do perl -d testReadLine.pl.
> Initially the Perl debugger works. I can do commands like l for list
> or s for step. However, as soon as I return from the new
> Term::ReadLine the debugger is confused. No command does anything.
>
> I fully suspect that the problem lies in the fact that both my Perl
> script and the Perl debugger are fighting over STDIN/STDOUT and
> confusing each other. The question is how to get them both to play
> nice.

It may also be because the debugger is also using Term::Readline::Gnu. I
don't know if the underlying readline library can cope with two users at
once. You may want to try the debugger options TTY and ReadLine (see
perldoc perldebug).

Ben